RFC 1757 - Remote Network Monitoring Management Information Base

[フレーム]

Network Working Group S. Waldbusser
Request for Comments: 1757 Carnegie Mellon University
Obsoletes: 1271 February 1995
Category: Standards Track
 Remote Network Monitoring Management Information Base
Status of this Memo
 This document specifies an Internet standards track protocol for the
 Internet community, and requests discussion and suggestions for
 improvements. Please refer to the current edition of the "Internet
 Official Protocol Standards" (STD 1) for the standardization state
 and status of this protocol. Distribution of this memo is unlimited.
Abstract
 This memo defines a portion of the Management Information Base (MIB)
 for use with network management protocols in TCP/IP-based internets.
 In particular, it defines objects for managing remote network
 monitoring devices.
Table of Contents
 1. The Network Management Framework ...................... 2
 2. Overview .............................................. 3
 2.1 Remote Network Management Goals ...................... 3
 2.2 Textual Conventions .................................. 5
 2.3 Structure of MIB ..................................... 5
 2.3.1 The Ethernet Statistics Group ...................... 6
 2.3.2 The History Control Group .......................... 6
 2.3.3 The Ethernet History Group ......................... 6
 2.3.4 The Alarm Group .................................... 6
 2.3.5 The Host Group ..................................... 6
 2.3.6 The HostTopN Group ................................. 7
 2.3.7 The Matrix Group ................................... 7
 2.3.8 The Filter Group ................................... 7
 2.3.9 The Packet Capture Group ........................... 7
 2.3.10 The Event Group ................................... 7
 3. Control of Remote Network Monitoring Devices .......... 7
 3.1 Resource Sharing Among Multiple Management Stations .. 8
 3.2 Row Addition Among Multiple Management Stations ...... 10
 4. Conventions ........................................... 11
 5. Definitions ........................................... 11
 6. Acknowledgments ....................................... 89
 7. References ............................................ 89
 8. Security Considerations ............................... 90
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 9. Author's Address ...................................... 90
 10. Appendix: Changes from RFC 1271 ...................... 91
1. The Network Management Framework
 The Internet-standard Network Management Framework consists of three
 components. They are:
 STD 16, RFC 1155 [1] which defines the SMI, the mechanisms used
 for describing and naming objects for the purpose of management.
 STD 16, RFC 1212 [2] defines a more concise description mechanism,
 which is wholly consistent with the SMI.
 STD 17, RFC 1213 [3] which defines MIB-II, the core set of managed
 objects for the Internet suite of protocols.
 STD 15, RFC 1157 [4] which defines the SNMP, the protocol used for
 network access to managed objects.
 The Framework permits new objects to be defined for the purpose of
 experimentation and evaluation.
 Managed objects are accessed via a virtual information store, termed
 the Management Information Base or MIB. Within a given MIB module,
 objects are defined using RFC 1212's OBJECT-TYPE macro. At a
 minimum, each object has a name, a syntax, an access-level, and an
 implementation-status.
 The name is an object identifier, an administratively assigned name,
 which specifies an object type. The object type together with an
 object instance serves to uniquely identify a specific instantiation
 of the object. For human convenience, we often use a textual string,
 termed the object descriptor, to also refer to the object type.
 The syntax of an object type defines the abstract data structure
 corresponding to that object type. The ASN.1[5] language is used for
 this purpose. However, RFC 1155 purposely restricts the ASN.1
 constructs which may be used. These restrictions are explicitly made
 for simplicity.
 The access-level of an object type defines whether it makes "protocol
 sense" to read and/or write the value of an instance of the object
 type. (This access-level is independent of any administrative
 authorization policy.)
 The implementation-status of an object type indicates whether the
 object is mandatory, optional, obsolete, or deprecated.
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2. Overview
 Remote network monitoring devices, often called monitors or probes,
 are instruments that exist for the purpose of managing a network.
 Often these remote probes are stand-alone devices and devote
 significant internal resources for the sole purpose of managing a
 network. An organization may employ many of these devices, one per
 network segment, to manage its internet. In addition, these devices
 may be used for a network management service provider to access a
 client network, often geographically remote.
 The objects defined in this document are intended as an interface
 between an RMON agent and an RMON management application and are not
 intended for direct manipulation by humans. While some users may
 tolerate the direct display of some of these objects, few will
 tolerate the complexity of manually manipulating objects to
 accomplish row creation. These functions should be handled by the
 management application.
 While most of the objects in this document are suitable for the
 management of any type of network, there are some which are specific
 to managing Ethernet networks. These are the objects in the
 etherStatsTable, the etherHistoryTable, and some attributes of the
 filterPktStatus and capturBufferPacketStatus objects. The design of
 this MIB allows similar objects to be defined for other network
 types. It is intended that future versions of this document and
 additional documents will define extensions for other network types
 such as Token Ring and FDDI.
2.1. Remote Network Management Goals
 o Offline Operation
 There are sometimes conditions when a management
 station will not be in constant contact with its
 remote monitoring devices. This is sometimes by
 design in an attempt to lower communications costs
 (especially when communicating over a WAN or
 dialup link), or by accident as network failures
 affect the communications between the management
 station and the probe.
 For this reason, this MIB allows a probe to be
 configured to perform diagnostics and to collect
 statistics continuously, even when communication with
 the management station may not be possible or
 efficient. The probe may then attempt to notify
 the management station when an exceptional condition
 occurs. Thus, even in circumstances where
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 communication between management station and probe is
 not continuous, fault, performance, and configuration
 information may be continuously accumulated and
 communicated to the management station conveniently
 and efficiently.
 o Proactive Monitoring
 Given the resources available on the monitor, it
 is potentially helpful for it continuously to run
 diagnostics and to log network performance. The
 monitor is always available at the onset of any
 failure. It can notify the management station of the
 failure and can store historical statistical
 information about the failure. This historical
 information can be played back by the management
 station in an attempt to perform further diagnosis
 into the cause of the problem.
 o Problem Detection and Reporting
 The monitor can be configured to recognize
 conditions, most notably error conditions, and
 continuously to check for them. When one of these
 conditions occurs, the event may be logged, and
 management stations may be notified in a number of
 ways.
 o Value Added Data
 Because a remote monitoring device represents a
 network resource dedicated exclusively to network
 management functions, and because it is located
 directly on the monitored portion of the network, the
 remote network monitoring device has the opportunity
 to add significant value to the data it collects.
 For instance, by highlighting those hosts on the
 network that generate the most traffic or errors, the
 probe can give the management station precisely the
 information it needs to solve a class of problems.
 o Multiple Managers
 An organization may have multiple management stations
 for different units of the organization, for different
 functions (e.g. engineering and operations), and in an
 attempt to provide disaster recovery. Because
 environments with multiple management stations are
 common, the remote network monitoring device has to
 deal with more than own management station,
 potentially using its resources concurrently.
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2.2. Textual Conventions
 Two new data types are introduced as a textual convention in this MIB
 document. These textual conventions enhance the readability of the
 specification and can ease comparison with other specifications if
 appropriate. It should be noted that the introduction of the these
 textual conventions has no effect on either the syntax nor the
 semantics of any managed objects. The use of these is merely an
 artifact of the explanatory method used. Objects defined in terms of
 one of these methods are always encoded by means of the rules that
 define the primitive type. Hence, no changes to the SMI or the SNMP
 are necessary to accommodate these textual conventions which are
 adopted merely for the convenience of readers and writers in pursuit
 of the elusive goal of clear, concise, and unambiguous MIB documents.
 The new data types are: OwnerString and EntryStatus.
2.3. Structure of MIB
 The objects are arranged into the following groups:
 - ethernet statistics
 - history control
 - ethernet history
 - alarm
 - host
 - hostTopN
 - matrix
 - filter
 - packet capture
 - event
 These groups are the basic unit of conformance. If a remote
 monitoring device implements a group, then it must implement all
 objects in that group. For example, a managed agent that implements
 the host group must implement the hostControlTable, the hostTable and
 the hostTimeTable.
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 All groups in this MIB are optional. Implementations of this MIB
 must also implement the system and interfaces group of MIB-II [6].
 MIB-II may also mandate the implementation of additional groups.
 These groups are defined to provide a means of assigning object
 identifiers, and to provide a method for managed agents to know which
 objects they must implement.
2.3.1. The Ethernet Statistics Group
 The ethernet statistics group contains statistics measured by the
 probe for each monitored Ethernet interface on this device. This
 group consists of the etherStatsTable. In the future other groups
 will be defined for other media types including Token Ring and FDDI.
 These groups should follow the same model as the ethernet statistics
 group.
2.3.2. The History Control Group
 The history control group controls the periodic statistical sampling
 of data from various types of networks. This group consists of the
 historyControlTable.
2.3.3. The Ethernet History Group
 The ethernet history group records periodic statistical samples from
 an ethernet network and stores them for later retrieval. This group
 consists of the etherHistoryTable. In the future, other groups will
 be defined for other media types including Token Ring and FDDI.
2.3.4. The Alarm Group
 The alarm group periodically takes statistical samples from variables
 in the probe and compares them to previously configured thresholds.
 If the monitored variable crosses a threshold, an event is generated.
 A hysteresis mechanism is implemented to limit the generation of
 alarms. This group consists of the alarmTable and requires the
 implementation of the event group.
2.3.5. The Host Group
 The host group contains statistics associated with each host
 discovered on the network. This group discovers hosts on the network
 by keeping a list of source and destination MAC Addresses seen in
 good packets promiscuously received from the network. This group
 consists of the hostControlTable, the hostTable, and the
 hostTimeTable.
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2.3.6. The HostTopN Group
 The hostTopN group is used to prepare reports that describe the hosts
 that top a list ordered by one of their statistics. The available
 statistics are samples of one of their base statistics over an
 interval specified by the management station. Thus, these statistics
 are rate based. The management station also selects how many such
 hosts are reported. This group consists of the hostTopNControlTable
 and the hostTopNTable, and requires the implementation of the host
 group.
2.3.7. The Matrix Group
 The matrix group stores statistics for conversations between sets of
 two addresses. As the device detects a new conversation, it creates
 a new entry in its tables. This group consists of the
 matrixControlTable, the matrixSDTable and the matrixDSTable.
2.3.8. The Filter Group
 The filter group allows packets to be matched by a filter equation.
 These matched packets form a data stream that may be captured or may
 generate events. This group consists of the filterTable and the
 channelTable.
2.3.9. The Packet Capture Group
 The Packet Capture group allows packets to be captured after they
 flow through a channel. This group consists of the
 bufferControlTable and the captureBufferTable, and requires the
 implementation of the filter group.
2.3.10. The Event Group
 The event group controls the generation and notification of events
 from this device. This group consists of the eventTable and the
 logTable.
3. Control of Remote Network Monitoring Devices
 Due to the complex nature of the available functions in these
 devices, the functions often need user configuration. In many cases,
 the function requires parameters to be set up for a data collection
 operation. The operation can proceed only after these parameters are
 fully set up.
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 Many functional groups in this MIB have one or more tables in which
 to set up control parameters, and one or more data tables in which to
 place the results of the operation. The control tables are typically
 read-write in nature, while the data tables are typically read-only.
 Because the parameters in the control table often describe resulting
 data in the data table, many of the parameters can be modified only
 when the control entry is invalid. Thus, the method for modifying
 these parameters is to invalidate the control entry, causing its
 deletion and the deletion of any associated data entries, and then
 create a new control entry with the proper parameters. Deleting the
 control entry also gives a convenient method for reclaiming the
 resources used by the associated data.
 Some objects in this MIB provide a mechanism to execute an action on
 the remote monitoring device. These objects may execute an action as
 a result of a change in the state of the object. For those objects
 in this MIB, a request to set an object to the same value as it
 currently holds would thus cause no action to occur.
 To facilitate control by multiple managers, resources have to be
 shared among the managers. These resources are typically the memory
 and computation resources that a function requires.
3.1. Resource Sharing Among Multiple Management Stations
 When multiple management stations wish to use functions that compete
 for a finite amount of resources on a device, a method to facilitate
 this sharing of resources is required. Potential conflicts include:
 o Two management stations wish to simultaneously use
 resources that together would exceed the capability of
 the device.
 o A management station uses a significant amount of
 resources for a long period of time.
 o A management station uses resources and then crashes,
 forgetting to free the resources so others may
 use them.
 A mechanism is provided for each management station initiated
 function in this MIB to avoid these conflicts and to help resolve
 them when they occur. Each function has a label identifying the
 initiator (owner) of the function. This label is set by the
 initiator to provide for the following possibilities:
 o A management station may recognize resources it owns
 and no longer needs.
 o A network operator can find the management station that
 owns the resource and negotiate for it to be freed.
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 o A network operator may decide to unilaterally free
 resources another network operator has reserved.
 o Upon initialization, a management station may recognize
 resources it had reserved in the past. With this
 information it may free the resources if it no longer
 needs them.
 Management stations and probes should support any format of the owner
 string dictated by the local policy of the organization. It is
 suggested that this name contain one or more of the following: IP
 address, management station name, network manager's name, location,
 or phone number. This information will help users to share the
 resources more effectively.
 There is often default functionality that the device or the
 administrator of the probe (often the network administrator) wishes
 to set up. The resources associated with this functionality are then
 owned by the device itself or by the network administrator, and are
 intended to be long-lived. In this case, the device or the
 administrator will set the relevant owner object to a string starting
 with 'monitor'. Indiscriminate modification of the monitor-owned
 configuration by network management stations is discouraged. In
 fact, a network management station should only modify these objects
 under the direction of the administrator of the probe.
 Resources on a probe are scarce and are typically allocated when
 control rows are created by an application. Since many applications
 may be using a probe simultaneously, indiscriminate allocation of
 resources to particular applications is very likely to cause resource
 shortages in the probe.
 When a network management station wishes to utilize a function in a
 monitor, it is encouraged to first scan the control table of that
 function to find an instance with similar parameters to share. This
 is especially true for those instances owned by the monitor, which
 can be assumed to change infrequently. If a management station
 decides to share an instance owned by another management station, it
 should understand that the management station that owns the instance
 may indiscriminately modify or delete it.
 It should be noted that a management application should have the most
 trust in a monitor-owned row because it should be changed very
 infrequently. A row owned by the management application is less
 long-lived because a network administrator is more likely to re-
 assign resources from a row that is in use by one user than from a
 monitor-owned row that is potentially in use by many users. A row
 owned by another application would be even less long-lived because
 the other application may delete or modify that row completely at its
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 discretion.
3.2. Row Addition Among Multiple Management Stations
 The addition of new rows is achieved using the method described in
 RFC 1212 [9]. In this MIB, rows are often added to a table in order
 to configure a function. This configuration usually involves
 parameters that control the operation of the function. The agent
 must check these parameters to make sure they are appropriate given
 restrictions defined in this MIB as well as any implementation
 specific restrictions such as lack of resources. The agent
 implementor may be confused as to when to check these parameters and
 when to signal to the management station that the parameters are
 invalid. There are two opportunities:
 o When the management station sets each parameter object.
 o When the management station sets the entry status object
 to valid.
 If the latter is chosen, it would be unclear to the management
 station which of the several parameters was invalid and caused the
 badValue error to be emitted. Thus, wherever possible, the
 implementor should choose the former as it will provide more
 information to the management station.
 A problem can arise when multiple management stations attempt to set
 configuration information simultaneously using SNMP. When this
 involves the addition of a new conceptual row in the same control
 table, the managers may collide, attempting to create the same entry.
 To guard against these collisions, each such control entry contains a
 status object with special semantics that help to arbitrate among the
 managers. If an attempt is made with the row addition mechanism to
 create such a status object and that object already exists, an error
 is returned. When more than one manager simultaneously attempts to
 create the same conceptual row, only the first will succeed. The
 others will receive an error.
 When a manager wishes to create a new control entry, it needs to
 choose an index for that row. It may choose this index in a variety
 of ways, hopefully minimizing the chances that the index is in use by
 another manager. If the index is in use, the mechanism mentioned
 previously will guard against collisions. Examples of schemes to
 choose index values include random selection or scanning the control
 table looking for the first unused index. Because index values may
 be any valid value in the range and they are chosen by the manager,
 the agent must allow a row to be created with any unused index value
 if it has the resources to create a new row.
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 Some tables in this MIB reference other tables within this MIB. When
 creating or deleting entries in these tables, it is generally
 allowable for dangling references to exist. There is no defined
 order for creating or deleting entries in these tables.
4. Conventions
 The following conventions are used throughout the RMON MIB and its
 companion documents.
 Good Packets
 Good packets are error-free packets that have a valid frame length.
 For example, on Ethernet, good packets are error-free packets that
 are between 64 octets long and 1518 octets long. They follow the
 form defined in IEEE 802.3 section 3.2.all.
 Bad Packets
 Bad packets are packets that have proper framing and are therefore
 recognized as packets, but contain errors within the packet or have
 an invalid length. For example, on Ethernet, bad packets have a
 valid preamble and SFD, but have a bad CRC, or are either shorter
 than 64 octets or longer than 1518 octets.
5. Definitions
 RMON-MIB DEFINITIONS ::= BEGIN
 IMPORTS
 Counter FROM RFC1155-SMI
 DisplayString FROM RFC1158-MIB
 mib-2 FROM RFC1213-MIB
 OBJECT-TYPE FROM RFC-1212
 TRAP-TYPE FROM RFC-1215;
 -- Remote Network Monitoring MIB
 rmon OBJECT IDENTIFIER ::= { mib-2 16 }
 -- textual conventions
 OwnerString ::= DisplayString
 -- This data type is used to model an administratively
 -- assigned name of the owner of a resource. This
 -- information is taken from the NVT ASCII character
 -- set. It is suggested that this name contain one or
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 -- more of the following: IP address, management station
 -- name, network manager's name, location, or phone
 -- number.
 -- In some cases the agent itself will be the owner of
 -- an entry. In these cases, this string shall be set
 -- to a string starting with 'monitor'.
 --
 -- SNMP access control is articulated entirely in terms
 -- of the contents of MIB views; access to a particular
 -- SNMP object instance depends only upon its presence
 -- or absence in a particular MIB view and never upon
 -- its value or the value of related object instances.
 -- Thus, objects of this type afford resolution of
 -- resource contention only among cooperating managers;
 -- they realize no access control function with respect
 -- to uncooperative parties.
 --
 -- By convention, objects with this syntax are declared as
 -- having
 --
 -- SIZE (0..127)
 EntryStatus ::= INTEGER
 { valid(1),
 createRequest(2),
 underCreation(3),
 invalid(4)
 }
 -- The status of a table entry.
 --
 -- Setting this object to the value invalid(4) has the
 -- effect of invalidating the corresponding entry.
 -- That is, it effectively disassociates the mapping
 -- identified with said entry.
 -- It is an implementation-specific matter as to whether
 -- the agent removes an invalidated entry from the table.
 -- Accordingly, management stations must be prepared to
 -- receive tabular information from agents that
 -- corresponds to entries currently not in use. Proper
 -- interpretation of such entries requires examination
 -- of the relevant EntryStatus object.
 --
 -- An existing instance of this object cannot be set to
 -- createRequest(2). This object may only be set to
 -- createRequest(2) when this instance is created. When
 -- this object is created, the agent may wish to create
 -- supplemental object instances with default values
 -- to complete a conceptual row in this table. Because
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 -- the creation of these default objects is entirely at
 -- the option of the agent, the manager must not assume
 -- that any will be created, but may make use of any that
 -- are created. Immediately after completing the create
 -- operation, the agent must set this object to
 -- underCreation(3).
 --
 -- When in the underCreation(3) state, an entry is
 -- allowed to exist in a possibly incomplete, possibly
 -- inconsistent state, usually to allow it to be
 -- modified in mutiple PDUs. When in this state, an
 -- entry is not fully active. Entries shall exist in
 -- the underCreation(3) state until the management
 -- station is finished configuring the entry and sets
 -- this object to valid(1) or aborts, setting this
 -- object to invalid(4). If the agent determines that
 -- an entry has been in the underCreation(3) state for
 -- an abnormally long time, it may decide that the
 -- management station has crashed. If the agent makes
 -- this decision, it may set this object to invalid(4)
 -- to reclaim the entry. A prudent agent will
 -- understand that the management station may need to
 -- wait for human input and will allow for that
 -- possibility in its determination of this abnormally
 -- long period.
 --
 -- An entry in the valid(1) state is fully configured and
 -- consistent and fully represents the configuration or
 -- operation such a row is intended to represent. For
 -- example, it could be a statistical function that is
 -- configured and active, or a filter that is available
 -- in the list of filters processed by the packet capture
 -- process.
 --
 -- A manager is restricted to changing the state of an
 -- entry in the following ways:
 --
 -- create under
 -- To: valid Request Creation invalid
 -- From:
 -- valid OK NO OK OK
 -- createRequest N/A N/A N/A N/A
 -- underCreation OK NO OK OK
 -- invalid NO NO NO OK
 -- nonExistent NO OK NO OK
 --
 -- In the table above, it is not applicable to move the
 -- state from the createRequest state to any other
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 -- state because the manager will never find the
 -- variable in that state. The nonExistent state is
 -- not a value of the enumeration, rather it means that
 -- the entryStatus variable does not exist at all.
 --
 -- An agent may allow an entryStatus variable to change
 -- state in additional ways, so long as the semantics
 -- of the states are followed. This allowance is made
 -- to ease the implementation of the agent and is made
 -- despite the fact that managers should never
 -- excercise these additional state transitions.
 statistics OBJECT IDENTIFIER ::= { rmon 1 }
 history OBJECT IDENTIFIER ::= { rmon 2 }
 alarm OBJECT IDENTIFIER ::= { rmon 3 }
 hosts OBJECT IDENTIFIER ::= { rmon 4 }
 hostTopN OBJECT IDENTIFIER ::= { rmon 5 }
 matrix OBJECT IDENTIFIER ::= { rmon 6 }
 filter OBJECT IDENTIFIER ::= { rmon 7 }
 capture OBJECT IDENTIFIER ::= { rmon 8 }
 event OBJECT IDENTIFIER ::= { rmon 9 }
 -- The Ethernet Statistics Group
 --
 -- Implementation of the Ethernet Statistics group is
 -- optional.
 --
 -- The ethernet statistics group contains statistics
 -- measured by the probe for each monitored interface on
 -- this device. These statistics take the form of free
 -- running counters that start from zero when a valid entry
 -- is created.
 --
 -- This group currently has statistics defined only for
 -- Ethernet interfaces. Each etherStatsEntry contains
 -- statistics for one Ethernet interface. The probe must
 -- create one etherStats entry for each monitored Ethernet
 -- interface on the device.
 etherStatsTable OBJECT-TYPE
 SYNTAX SEQUENCE OF EtherStatsEntry
 ACCESS not-accessible
 STATUS mandatory
 DESCRIPTION
 "A list of Ethernet statistics entries."
 ::= { statistics 1 }
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 etherStatsEntry OBJECT-TYPE
 SYNTAX EtherStatsEntry
 ACCESS not-accessible
 STATUS mandatory
 DESCRIPTION
 "A collection of statistics kept for a particular
 Ethernet interface. As an example, an instance of the
 etherStatsPkts object might be named etherStatsPkts.1"
 INDEX { etherStatsIndex }
 ::= { etherStatsTable 1 }
 EtherStatsEntry ::= SEQUENCE {
 etherStatsIndex INTEGER (1..65535),
 etherStatsDataSource OBJECT IDENTIFIER,
 etherStatsDropEvents Counter,
 etherStatsOctets Counter,
 etherStatsPkts Counter,
 etherStatsBroadcastPkts Counter,
 etherStatsMulticastPkts Counter,
 etherStatsCRCAlignErrors Counter,
 etherStatsUndersizePkts Counter,
 etherStatsOversizePkts Counter,
 etherStatsFragments Counter,
 etherStatsJabbers Counter,
 etherStatsCollisions Counter,
 etherStatsPkts64Octets Counter,
 etherStatsPkts65to127Octets Counter,
 etherStatsPkts128to255Octets Counter,
 etherStatsPkts256to511Octets Counter,
 etherStatsPkts512to1023Octets Counter,
 etherStatsPkts1024to1518Octets Counter,
 etherStatsOwner OwnerString,
 etherStatsStatus EntryStatus
 }
 etherStatsIndex OBJECT-TYPE
 SYNTAX INTEGER (1..65535)
 ACCESS read-only
 STATUS mandatory
 DESCRIPTION
 "The value of this object uniquely identifies this
 etherStats entry."
 ::= { etherStatsEntry 1 }
 etherStatsDataSource OBJECT-TYPE
 SYNTAX OBJECT IDENTIFIER
 ACCESS read-write
 STATUS mandatory
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 DESCRIPTION
 "This object identifies the source of the data that
 this etherStats entry is configured to analyze. This
 source can be any ethernet interface on this device.
 In order to identify a particular interface, this
 object shall identify the instance of the ifIndex
 object, defined in RFC 1213 and RFC 1573 [4,6], for
 the desired interface. For example, if an entry
 were to receive data from interface #1, this object
 would be set to ifIndex.1.
 The statistics in this group reflect all packets
 on the local network segment attached to the
 identified interface.
 An agent may or may not be able to tell if
 fundamental changes to the media of the interface
 have occurred and necessitate an invalidation of
 this entry. For example, a hot-pluggable ethernet
 card could be pulled out and replaced by a
 token-ring card. In such a case, if the agent has
 such knowledge of the change, it is recommended that
 it invalidate this entry.
 This object may not be modified if the associated
 etherStatsStatus object is equal to valid(1)."
 ::= { etherStatsEntry 2 }
 etherStatsDropEvents OBJECT-TYPE
 SYNTAX Counter
 ACCESS read-only
 STATUS mandatory
 DESCRIPTION
 "The total number of events in which packets
 were dropped by the probe due to lack of resources.
 Note that this number is not necessarily the number of
 packets dropped; it is just the number of times this
 condition has been detected."
 ::= { etherStatsEntry 3 }
 etherStatsOctets OBJECT-TYPE
 SYNTAX Counter
 ACCESS read-only
 STATUS mandatory
 DESCRIPTION
 "The total number of octets of data (including
 those in bad packets) received on the
 network (excluding framing bits but including
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 FCS octets).
 This object can be used as a reasonable estimate of
 ethernet utilization. If greater precision is
 desired, the etherStatsPkts and etherStatsOctets
 objects should be sampled before and after a common
 interval. The differences in the sampled values are
 Pkts and Octets, respectively, and the number of
 seconds in the interval is Interval. These values
 are used to calculate the Utilization as follows:
 Pkts * (9.6 + 6.4) + (Octets * .8)
 Utilization = -------------------------------------
 Interval * 10,000
 The result of this equation is the value Utilization
 which is the percent utilization of the ethernet
 segment on a scale of 0 to 100 percent."
 ::= { etherStatsEntry 4 }
 etherStatsPkts OBJECT-TYPE
 SYNTAX Counter
 ACCESS read-only
 STATUS mandatory
 DESCRIPTION
 "The total number of packets (including bad packets,
 broadcast packets, and multicast packets) received."
 ::= { etherStatsEntry 5 }
 etherStatsBroadcastPkts OBJECT-TYPE
 SYNTAX Counter
 ACCESS read-only
 STATUS mandatory
 DESCRIPTION
 "The total number of good packets received that were
 directed to the broadcast address. Note that this
 does not include multicast packets."
 ::= { etherStatsEntry 6 }
 etherStatsMulticastPkts OBJECT-TYPE
 SYNTAX Counter
 ACCESS read-only
 STATUS mandatory
 DESCRIPTION
 "The total number of good packets received that were
 directed to a multicast address. Note that this
 number does not include packets directed to the
 broadcast address."
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RFC 1757 Remote Network Monitoring MIB February 1995
 ::= { etherStatsEntry 7 }
 etherStatsCRCAlignErrors OBJECT-TYPE
 SYNTAX Counter
 ACCESS read-only
 STATUS mandatory
 DESCRIPTION
 "The total number of packets received that
 had a length (excluding framing bits, but
 including FCS octets) of between 64 and 1518
 octets, inclusive, but but had either a bad
 Frame Check Sequence (FCS) with an integral
 number of octets (FCS Error) or a bad FCS with
 a non-integral number of octets (Alignment Error)."
 ::= { etherStatsEntry 8 }
 etherStatsUndersizePkts OBJECT-TYPE
 SYNTAX Counter
 ACCESS read-only
 STATUS mandatory
 DESCRIPTION
 "The total number of packets received that were
 less than 64 octets long (excluding framing bits,
 but including FCS octets) and were otherwise well
 formed."
 ::= { etherStatsEntry 9 }
 etherStatsOversizePkts OBJECT-TYPE
 SYNTAX Counter
 ACCESS read-only
 STATUS mandatory
 DESCRIPTION
 "The total number of packets received that were
 longer than 1518 octets (excluding framing bits,
 but including FCS octets) and were otherwise
 well formed."
 ::= { etherStatsEntry 10 }
 etherStatsFragments OBJECT-TYPE
 SYNTAX Counter
 ACCESS read-only
 STATUS mandatory
 DESCRIPTION
 "The total number of packets received that were less
 than 64 octets in length (excluding framing bits but
 including FCS octets) and had either a bad Frame
 Check Sequence (FCS) with an integral number of
 octets (FCS Error) or a bad FCS with a non-integral
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RFC 1757 Remote Network Monitoring MIB February 1995
 number of octets (Alignment Error).
 Note that it is entirely normal for
 etherStatsFragments to increment. This is because
 it counts both runts (which are normal occurrences
 due to collisions) and noise hits."
 ::= { etherStatsEntry 11 }
 etherStatsJabbers OBJECT-TYPE
 SYNTAX Counter
 ACCESS read-only
 STATUS mandatory
 DESCRIPTION
 "The total number of packets received that were
 longer than 1518 octets (excluding framing bits,
 but including FCS octets), and had either a bad
 Frame Check Sequence (FCS) with an integral number
 of octets (FCS Error) or a bad FCS with a
 non-integral number of octets (Alignment Error).
 Note that this definition of jabber is different
 than the definition in IEEE-802.3 section 8.2.1.5
 (10BASE5) and section 10.3.1.4 (10BASE2). These
 documents define jabber as the condition where any
 packet exceeds 20 ms. The allowed range to detect
 jabber is between 20 ms and 150 ms."
 ::= { etherStatsEntry 12 }
 etherStatsCollisions OBJECT-TYPE
 SYNTAX Counter
 ACCESS read-only
 STATUS mandatory
 DESCRIPTION
 "The best estimate of the total number of collisions
 on this Ethernet segment.
 The value returned will depend on the location of
 the RMON probe. Section 8.2.1.3 (10BASE-5) and
 section 10.3.1.3 (10BASE-2) of IEEE standard 802.3
 states that a station must detect a collision, in
 the receive mode, if three or more stations are
 transmitting simultaneously. A repeater port must
 detect a collision when two or more stations are
 transmitting simultaneously. Thus a probe placed on
 a repeater port could record more collisions than a
 probe connected to a station on the same segment
 would.
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RFC 1757 Remote Network Monitoring MIB February 1995
 Probe location plays a much smaller role when
 considering 10BASE-T. 14.2.1.4 (10BASE-T) of IEEE
 standard 802.3 defines a collision as the
 simultaneous presence of signals on the DO and RD
 circuits (transmitting and receiving at the same
 time). A 10BASE-T station can only detect
 collisions when it is transmitting. Thus probes
 placed on a station and a repeater, should report
 the same number of collisions.
 Note also that an RMON probe inside a repeater
 should ideally report collisions between the
 repeater and one or more other hosts (transmit
 collisions as defined by IEEE 802.3k) plus receiver
 collisions observed on any coax segments to which
 the repeater is connected."
 ::= { etherStatsEntry 13 }
 etherStatsPkts64Octets OBJECT-TYPE
 SYNTAX Counter
 ACCESS read-only
 STATUS mandatory
 DESCRIPTION
 "The total number of packets (including bad
 packets) received that were 64 octets in length
 (excluding framing bits but including FCS octets)."
 ::= { etherStatsEntry 14 }
 etherStatsPkts65to127Octets OBJECT-TYPE
 SYNTAX Counter
 ACCESS read-only
 STATUS mandatory
 DESCRIPTION
 "The total number of packets (including bad
 packets) received that were between
 65 and 127 octets in length inclusive
 (excluding framing bits but including FCS octets)."
 ::= { etherStatsEntry 15 }
 etherStatsPkts128to255Octets OBJECT-TYPE
 SYNTAX Counter
 ACCESS read-only
 STATUS mandatory
 DESCRIPTION
 "The total number of packets (including bad
 packets) received that were between
 128 and 255 octets in length inclusive
 (excluding framing bits but including FCS octets)."
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RFC 1757 Remote Network Monitoring MIB February 1995
 ::= { etherStatsEntry 16 }
 etherStatsPkts256to511Octets OBJECT-TYPE
 SYNTAX Counter
 ACCESS read-only
 STATUS mandatory
 DESCRIPTION
 "The total number of packets (including bad
 packets) received that were between
 256 and 511 octets in length inclusive
 (excluding framing bits but including FCS octets)."
 ::= { etherStatsEntry 17 }
 etherStatsPkts512to1023Octets OBJECT-TYPE
 SYNTAX Counter
 ACCESS read-only
 STATUS mandatory
 DESCRIPTION
 "The total number of packets (including bad
 packets) received that were between
 512 and 1023 octets in length inclusive
 (excluding framing bits but including FCS octets)."
 ::= { etherStatsEntry 18 }
 etherStatsPkts1024to1518Octets OBJECT-TYPE
 SYNTAX Counter
 ACCESS read-only
 STATUS mandatory
 DESCRIPTION
 "The total number of packets (including bad
 packets) received that were between
 1024 and 1518 octets in length inclusive
 (excluding framing bits but including FCS octets)."
 ::= { etherStatsEntry 19 }
 etherStatsOwner OBJECT-TYPE
 SYNTAX OwnerString
 ACCESS read-write
 STATUS mandatory
 DESCRIPTION
 "The entity that configured this entry and is
 therefore using the resources assigned to it."
 ::= { etherStatsEntry 20 }
 etherStatsStatus OBJECT-TYPE
 SYNTAX EntryStatus
 ACCESS read-write
 STATUS mandatory
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RFC 1757 Remote Network Monitoring MIB February 1995
 DESCRIPTION
 "The status of this etherStats entry."
 ::= { etherStatsEntry 21 }
 -- The History Control Group
 -- Implementation of the History Control group is optional.
 --
 -- The history control group controls the periodic statistical
 -- sampling of data from various types of networks. The
 -- historyControlTable stores configuration entries that each
 -- define an interface, polling period, and other parameters.
 -- Once samples are taken, their data is stored in an entry
 -- in a media-specific table. Each such entry defines one
 -- sample, and is associated with the historyControlEntry that
 -- caused the sample to be taken. Each counter in the
 -- etherHistoryEntry counts the same event as its
 -- similarly-named counterpart in the etherStatsEntry,
 -- except that each value here is a cumulative sum during a
 -- sampling period.
 --
 -- If the probe keeps track of the time of day, it should
 -- start the first sample of the history at a time such that
 -- when the next hour of the day begins, a sample is
 -- started at that instant. This tends to make more
 -- user-friendly reports, and enables comparison of reports
 -- from different probes that have relatively accurate time
 -- of day.
 --
 -- The probe is encouraged to add two history control entries
 -- per monitored interface upon initialization that describe
 -- a short term and a long term polling period. Suggested
 -- parameters are 30 seconds for the short term polling period
 -- and 30 minutes for the long term period.
 historyControlTable OBJECT-TYPE
 SYNTAX SEQUENCE OF HistoryControlEntry
 ACCESS not-accessible
 STATUS mandatory
 DESCRIPTION
 "A list of history control entries."
 ::= { history 1 }
 historyControlEntry OBJECT-TYPE
 SYNTAX HistoryControlEntry
 ACCESS not-accessible
 STATUS mandatory
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RFC 1757 Remote Network Monitoring MIB February 1995
 DESCRIPTION
 "A list of parameters that set up a periodic sampling
 of statistics. As an example, an instance of the
 historyControlInterval object might be named
 historyControlInterval.2"
 INDEX { historyControlIndex }
 ::= { historyControlTable 1 }
 HistoryControlEntry ::= SEQUENCE {
 historyControlIndex INTEGER (1..65535),
 historyControlDataSource OBJECT IDENTIFIER,
 historyControlBucketsRequested INTEGER (1..65535),
 historyControlBucketsGranted INTEGER (1..65535),
 historyControlInterval INTEGER (1..3600),
 historyControlOwner OwnerString,
 historyControlStatus EntryStatus
 }
 historyControlIndex OBJECT-TYPE
 SYNTAX INTEGER (1..65535)
 ACCESS read-only
 STATUS mandatory
 DESCRIPTION
 "An index that uniquely identifies an entry in the
 historyControl table. Each such entry defines a
 set of samples at a particular interval for an
 interface on the device."
 ::= { historyControlEntry 1 }
 historyControlDataSource OBJECT-TYPE
 SYNTAX OBJECT IDENTIFIER
 ACCESS read-write
 STATUS mandatory
 DESCRIPTION
 "This object identifies the source of the data for
 which historical data was collected and
 placed in a media-specific table on behalf of this
 historyControlEntry. This source can be any
 interface on this device. In order to identify
 a particular interface, this object shall identify
 the instance of the ifIndex object, defined
 in RFC 1213 and RFC 1573 [4,6], for the desired
 interface. For example, if an entry were to receive
 data from interface #1, this object would be set
 to ifIndex.1.
 The statistics in this group reflect all packets
 on the local network segment attached to the
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RFC 1757 Remote Network Monitoring MIB February 1995
 identified interface.
 An agent may or may not be able to tell if fundamental
 changes to the media of the interface have occurred
 and necessitate an invalidation of this entry. For
 example, a hot-pluggable ethernet card could be
 pulled out and replaced by a token-ring card. In
 such a case, if the agent has such knowledge of the
 change, it is recommended that it invalidate this
 entry.
 This object may not be modified if the associated
 historyControlStatus object is equal to valid(1)."
 ::= { historyControlEntry 2 }
 historyControlBucketsRequested OBJECT-TYPE
 SYNTAX INTEGER (1..65535)
 ACCESS read-write
 STATUS mandatory
 DESCRIPTION
 "The requested number of discrete time intervals
 over which data is to be saved in the part of the
 media-specific table associated with this
 historyControlEntry.
 When this object is created or modified, the probe
 should set historyControlBucketsGranted as closely to
 this object as is possible for the particular probe
 implementation and available resources."
 DEFVAL { 50 }
 ::= { historyControlEntry 3 }
 historyControlBucketsGranted OBJECT-TYPE
 SYNTAX INTEGER (1..65535)
 ACCESS read-only
 STATUS mandatory
 DESCRIPTION
 "The number of discrete sampling intervals
 over which data shall be saved in the part of
 the media-specific table associated with this
 historyControlEntry.
 When the associated historyControlBucketsRequested
 object is created or modified, the probe
 should set this object as closely to the requested
 value as is possible for the particular
 probe implementation and available resources. The
 probe must not lower this value except as a result
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RFC 1757 Remote Network Monitoring MIB February 1995
 of a modification to the associated
 historyControlBucketsRequested object.
 There will be times when the actual number of
 buckets associated with this entry is less than
 the value of this object. In this case, at the
 end of each sampling interval, a new bucket will
 be added to the media-specific table.
 When the number of buckets reaches the value of
 this object and a new bucket is to be added to the
 media-specific table, the oldest bucket associated
 with this historyControlEntry shall be deleted by
 the agent so that the new bucket can be added.
 When the value of this object changes to a value less
 than the current value, entries are deleted
 from the media-specific table associated with this
 historyControlEntry. Enough of the oldest of these
 entries shall be deleted by the agent so that their
 number remains less than or equal to the new value of
 this object.
 When the value of this object changes to a value
 greater than the current value, the number of
 associated media- specific entries may be allowed to
 grow."
 ::= { historyControlEntry 4 }
 historyControlInterval OBJECT-TYPE
 SYNTAX INTEGER (1..3600)
 ACCESS read-write
 STATUS mandatory
 DESCRIPTION
 "The interval in seconds over which the data is
 sampled for each bucket in the part of the
 media-specific table associated with this
 historyControlEntry. This interval can
 be set to any number of seconds between 1 and
 3600 (1 hour).
 Because the counters in a bucket may overflow at their
 maximum value with no indication, a prudent manager
 will take into account the possibility of overflow
 in any of the associated counters. It is important
 to consider the minimum time in which any counter
 could overflow on a particular media type and set
 the historyControlInterval object to a value less
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RFC 1757 Remote Network Monitoring MIB February 1995
 than this interval. This is typically most
 important for the 'octets' counter in any
 media-specific table. For example, on an Ethernet
 network, the etherHistoryOctets counter could
 overflow in about one hour at the Ethernet's maximum
 utilization.
 This object may not be modified if the associated
 historyControlStatus object is equal to valid(1)."
 DEFVAL { 1800 }
 ::= { historyControlEntry 5 }
 historyControlOwner OBJECT-TYPE
 SYNTAX OwnerString
 ACCESS read-write
 STATUS mandatory
 DESCRIPTION
 "The entity that configured this entry and is
 therefore using the resources assigned to it."
 ::= { historyControlEntry 6 }
 historyControlStatus OBJECT-TYPE
 SYNTAX EntryStatus
 ACCESS read-write
 STATUS mandatory
 DESCRIPTION
 "The status of this historyControl entry.
 Each instance of the media-specific table associated
 with this historyControlEntry will be deleted by the
 agent if this historyControlEntry is not equal to
 valid(1)."
 ::= { historyControlEntry 7 }
 -- The Ethernet History Group
 -- Implementation of the Ethernet History group is optional.
 --
 -- The Ethernet History group records periodic
 -- statistical samples from a network and stores them
 -- for later retrieval. Once samples are taken, their
 -- data is stored in an entry in a media-specific
 -- table. Each such entry defines one sample, and is
 -- associated with the historyControlEntry that caused
 -- the sample to be taken. This group defines the
 -- etherHistoryTable, for Ethernet networks.
 --
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RFC 1757 Remote Network Monitoring MIB February 1995
 etherHistoryTable OBJECT-TYPE
 SYNTAX SEQUENCE OF EtherHistoryEntry
 ACCESS not-accessible
 STATUS mandatory
 DESCRIPTION
 "A list of Ethernet history entries."
 ::= { history 2 }
 etherHistoryEntry OBJECT-TYPE
 SYNTAX EtherHistoryEntry
 ACCESS not-accessible
 STATUS mandatory
 DESCRIPTION
 "An historical sample of Ethernet statistics on a
 particular Ethernet interface. This sample is
 associated with the historyControlEntry which set up
 the parameters for a regular collection of these
 samples. As an example, an instance of the
 etherHistoryPkts object might be named
 etherHistoryPkts.2.89"
 INDEX { etherHistoryIndex , etherHistorySampleIndex }
 ::= { etherHistoryTable 1 }
 EtherHistoryEntry ::= SEQUENCE {
 etherHistoryIndex INTEGER (1..65535),
 etherHistorySampleIndex INTEGER (1..2147483647),
 etherHistoryIntervalStart TimeTicks,
 etherHistoryDropEvents Counter,
 etherHistoryOctets Counter,
 etherHistoryPkts Counter,
 etherHistoryBroadcastPkts Counter,
 etherHistoryMulticastPkts Counter,
 etherHistoryCRCAlignErrors Counter,
 etherHistoryUndersizePkts Counter,
 etherHistoryOversizePkts Counter,
 etherHistoryFragments Counter,
 etherHistoryJabbers Counter,
 etherHistoryCollisions Counter,
 etherHistoryUtilization INTEGER (0..10000)
 }
 etherHistoryIndex OBJECT-TYPE
 SYNTAX INTEGER (1..65535)
 ACCESS read-only
 STATUS mandatory
 DESCRIPTION
 "The history of which this entry is a part. The
 history identified by a particular value of this
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RFC 1757 Remote Network Monitoring MIB February 1995
 index is the same history as identified
 by the same value of historyControlIndex."
 ::= { etherHistoryEntry 1 }
 etherHistorySampleIndex OBJECT-TYPE
 SYNTAX INTEGER (1..2147483647)
 ACCESS read-only
 STATUS mandatory
 DESCRIPTION
 "An index that uniquely identifies the particular
 sample this entry represents among all samples
 associated with the same historyControlEntry.
 This index starts at 1 and increases by one
 as each new sample is taken."
 ::= { etherHistoryEntry 2 }
 etherHistoryIntervalStart OBJECT-TYPE
 SYNTAX TimeTicks
 ACCESS read-only
 STATUS mandatory
 DESCRIPTION
 "The value of sysUpTime at the start of the interval
 over which this sample was measured. If the probe
 keeps track of the time of day, it should start
 the first sample of the history at a time such that
 when the next hour of the day begins, a sample is
 started at that instant. Note that following this
 rule may require the probe to delay collecting the
 first sample of the history, as each sample must be
 of the same interval. Also note that the sample which
 is currently being collected is not accessible in this
 table until the end of its interval."
 ::= { etherHistoryEntry 3 }
 etherHistoryDropEvents OBJECT-TYPE
 SYNTAX Counter
 ACCESS read-only
 STATUS mandatory
 DESCRIPTION
 "The total number of events in which packets
 were dropped by the probe due to lack of resources
 during this sampling interval. Note that this number
 is not necessarily the number of packets dropped, it
 is just the number of times this condition has been
 detected."
 ::= { etherHistoryEntry 4 }
 etherHistoryOctets OBJECT-TYPE
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RFC 1757 Remote Network Monitoring MIB February 1995
 SYNTAX Counter
 ACCESS read-only
 STATUS mandatory
 DESCRIPTION
 "The total number of octets of data (including
 those in bad packets) received on the
 network (excluding framing bits but including
 FCS octets)."
 ::= { etherHistoryEntry 5 }
 etherHistoryPkts OBJECT-TYPE
 SYNTAX Counter
 ACCESS read-only
 STATUS mandatory
 DESCRIPTION
 "The number of packets (including bad packets)
 received during this sampling interval."
 ::= { etherHistoryEntry 6 }
 etherHistoryBroadcastPkts OBJECT-TYPE
 SYNTAX Counter
 ACCESS read-only
 STATUS mandatory
 DESCRIPTION
 "The number of good packets received during this
 sampling interval that were directed to the
 broadcast address."
 ::= { etherHistoryEntry 7 }
 etherHistoryMulticastPkts OBJECT-TYPE
 SYNTAX Counter
 ACCESS read-only
 STATUS mandatory
 DESCRIPTION
 "The number of good packets received during this
 sampling interval that were directed to a
 multicast address. Note that this number does not
 include packets addressed to the broadcast address."
 ::= { etherHistoryEntry 8 }
 etherHistoryCRCAlignErrors OBJECT-TYPE
 SYNTAX Counter
 ACCESS read-only
 STATUS mandatory
 DESCRIPTION
 "The number of packets received during this sampling
 interval that had a length (excluding framing bits
 but including FCS octets) between 64 and 1518
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RFC 1757 Remote Network Monitoring MIB February 1995
 octets, inclusive, but had either a bad Frame Check
 Sequence (FCS) with an integral number of octets
 (FCS Error) or a bad FCS with a non-integral number
 of octets (Alignment Error)."
 ::= { etherHistoryEntry 9 }
 etherHistoryUndersizePkts OBJECT-TYPE
 SYNTAX Counter
 ACCESS read-only
 STATUS mandatory
 DESCRIPTION
 "The number of packets received during this
 sampling interval that were less than 64 octets
 long (excluding framing bits but including FCS
 octets) and were otherwise well formed."
 ::= { etherHistoryEntry 10 }
 etherHistoryOversizePkts OBJECT-TYPE
 SYNTAX Counter
 ACCESS read-only
 STATUS mandatory
 DESCRIPTION
 "The number of packets received during this
 sampling interval that were longer than 1518
 octets (excluding framing bits but including
 FCS octets) but were otherwise well formed."
 ::= { etherHistoryEntry 11 }
 etherHistoryFragments OBJECT-TYPE
 SYNTAX Counter
 ACCESS read-only
 STATUS mandatory
 DESCRIPTION
 "The total number of packets received during this
 sampling interval that were less than 64 octets in
 length (excluding framing bits but including FCS
 octets) had either a bad Frame Check Sequence (FCS)
 with an integral number of octets (FCS Error) or a bad
 FCS with a non-integral number of octets (Alignment
 Error).
 Note that it is entirely normal for
 etherHistoryFragments to increment. This is because
 it counts both runts (which are normal occurrences
 due to collisions) and noise hits."
 ::= { etherHistoryEntry 12 }
 etherHistoryJabbers OBJECT-TYPE
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RFC 1757 Remote Network Monitoring MIB February 1995
 SYNTAX Counter
 ACCESS read-only
 STATUS mandatory
 DESCRIPTION
 "The number of packets received during this
 sampling interval that were longer than 1518 octets
 (excluding framing bits but including FCS octets),
 and had either a bad Frame Check Sequence (FCS)
 with an integral number of octets (FCS Error) or
 a bad FCS with a non-integral number of octets
 (Alignment Error).
 Note that this definition of jabber is different
 than the definition in IEEE-802.3 section 8.2.1.5
 (10BASE5) and section 10.3.1.4 (10BASE2). These
 documents define jabber as the condition where any
 packet exceeds 20 ms. The allowed range to detect
 jabber is between 20 ms and 150 ms."
 ::= { etherHistoryEntry 13 }
 etherHistoryCollisions OBJECT-TYPE
 SYNTAX Counter
 ACCESS read-only
 STATUS mandatory
 DESCRIPTION
 "The best estimate of the total number of collisions
 on this Ethernet segment during this sampling
 interval.
 The value returned will depend on the location of
 the RMON probe. Section 8.2.1.3 (10BASE-5) and
 section 10.3.1.3 (10BASE-2) of IEEE standard 802.3
 states that a station must detect a collision, in
 the receive mode, if three or more stations are
 transmitting simultaneously. A repeater port must
 detect a collision when two or more stations are
 transmitting simultaneously. Thus a probe placed on
 a repeater port could record more collisions than a
 probe connected to a station on the same segment
 would.
 Probe location plays a much smaller role when
 considering 10BASE-T. 14.2.1.4 (10BASE-T) of IEEE
 standard 802.3 defines a collision as the
 simultaneous presence of signals on the DO and RD
 circuits (transmitting and receiving at the same
 time). A 10BASE-T station can only detect
 collisions when it is transmitting. Thus probes
Waldbusser [Page 31]

RFC 1757 Remote Network Monitoring MIB February 1995
 placed on a station and a repeater, should report
 the same number of collisions.
 Note also that an RMON probe inside a repeater
 should ideally report collisions between the
 repeater and one or more other hosts (transmit
 collisions as defined by IEEE 802.3k) plus receiver
 collisions observed on any coax segments to which
 the repeater is connected."
 ::= { etherHistoryEntry 14 }
 etherHistoryUtilization OBJECT-TYPE
 SYNTAX INTEGER (0..10000)
 ACCESS read-only
 STATUS mandatory
 DESCRIPTION
 "The best estimate of the mean physical layer
 network utilization on this interface during this
 sampling interval, in hundredths of a percent."
 ::= { etherHistoryEntry 15 }
 -- The Alarm Group
 -- Implementation of the Alarm group is optional.
 --
 -- The Alarm Group requires the implementation of the Event
 -- group.
 --
 -- The Alarm group periodically takes
 -- statistical samples from variables in the probe and
 -- compares them to thresholds that have been
 -- configured. The alarm table stores configuration
 -- entries that each define a variable, polling period,
 -- and threshold parameters. If a sample is found to
 -- cross the threshold values, an event is generated.
 -- Only variables that resolve to an ASN.1 primitive
 -- type of INTEGER (INTEGER, Counter, Gauge, or
 -- TimeTicks) may be monitored in this way.
 --
 -- This function has a hysteresis mechanism to limit
 -- the generation of events. This mechanism generates
 -- one event as a threshold is crossed in the
 -- appropriate direction. No more events are generated
 -- for that threshold until the opposite threshold is
 -- crossed.
 --
 -- In the case of a sampling a deltaValue, a probe may
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RFC 1757 Remote Network Monitoring MIB February 1995
 -- implement this mechanism with more precision if it
 -- takes a delta sample twice per period, each time
 -- comparing the sum of the latest two samples to the
 -- threshold. This allows the detection of threshold
 -- crossings that span the sampling boundary. Note
 -- that this does not require any special configuration
 -- of the threshold value. It is suggested that probes
 -- implement this more precise algorithm.
 alarmTable OBJECT-TYPE
 SYNTAX SEQUENCE OF AlarmEntry
 ACCESS not-accessible
 STATUS mandatory
 DESCRIPTION
 "A list of alarm entries."
 ::= { alarm 1 }
 alarmEntry OBJECT-TYPE
 SYNTAX AlarmEntry
 ACCESS not-accessible
 STATUS mandatory
 DESCRIPTION
 "A list of parameters that set up a periodic checking
 for alarm conditions. For example, an instance of the
 alarmValue object might be named alarmValue.8"
 INDEX { alarmIndex }
 ::= { alarmTable 1 }
 AlarmEntry ::= SEQUENCE {
 alarmIndex INTEGER (1..65535),
 alarmInterval INTEGER,
 alarmVariable OBJECT IDENTIFIER,
 alarmSampleType INTEGER,
 alarmValue INTEGER,
 alarmStartupAlarm INTEGER,
 alarmRisingThreshold INTEGER,
 alarmFallingThreshold INTEGER,
 alarmRisingEventIndex INTEGER (0..65535),
 alarmFallingEventIndex INTEGER (0..65535),
 alarmOwner OwnerString,
 alarmStatus EntryStatus
 }
 alarmIndex OBJECT-TYPE
 SYNTAX INTEGER (1..65535)
 ACCESS read-only
 STATUS mandatory
 DESCRIPTION
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RFC 1757 Remote Network Monitoring MIB February 1995
 "An index that uniquely identifies an entry in the
 alarm table. Each such entry defines a
 diagnostic sample at a particular interval
 for an object on the device."
 ::= { alarmEntry 1 }
 alarmInterval OBJECT-TYPE
 SYNTAX INTEGER
 ACCESS read-write
 STATUS mandatory
 DESCRIPTION
 "The interval in seconds over which the data is
 sampled and compared with the rising and falling
 thresholds. When setting this variable, care
 should be taken in the case of deltaValue
 sampling - the interval should be set short enough
 that the sampled variable is very unlikely to
 increase or decrease by more than 2^31 - 1 during
 a single sampling interval.
 This object may not be modified if the associated
 alarmStatus object is equal to valid(1)."
 ::= { alarmEntry 2 }
 alarmVariable OBJECT-TYPE
 SYNTAX OBJECT IDENTIFIER
 ACCESS read-write
 STATUS mandatory
 DESCRIPTION
 "The object identifier of the particular variable to
 be sampled. Only variables that resolve to an ASN.1
 primitive type of INTEGER (INTEGER, Counter, Gauge,
 or TimeTicks) may be sampled.
 Because SNMP access control is articulated entirely
 in terms of the contents of MIB views, no access
 control mechanism exists that can restrict the value
 of this object to identify only those objects that
 exist in a particular MIB view. Because there is
 thus no acceptable means of restricting the read
 access that could be obtained through the alarm
 mechanism, the probe must only grant write access to
 this object in those views that have read access to
 all objects on the probe.
 During a set operation, if the supplied variable
 name is not available in the selected MIB view, a
 badValue error must be returned. If at any time the
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RFC 1757 Remote Network Monitoring MIB February 1995
 variable name of an established alarmEntry is no
 longer available in the selected MIB view, the probe
 must change the status of this alarmEntry to
 invalid(4).
 This object may not be modified if the associated
 alarmStatus object is equal to valid(1)."
 ::= { alarmEntry 3 }
 alarmSampleType OBJECT-TYPE
 SYNTAX INTEGER {
 absoluteValue(1),
 deltaValue(2)
 }
 ACCESS read-write
 STATUS mandatory
 DESCRIPTION
 "The method of sampling the selected variable and
 calculating the value to be compared against the
 thresholds. If the value of this object is
 absoluteValue(1), the value of the selected variable
 will be compared directly with the thresholds at the
 end of the sampling interval. If the value of this
 object is deltaValue(2), the value of the selected
 variable at the last sample will be subtracted from
 the current value, and the difference compared with
 the thresholds.
 This object may not be modified if the associated
 alarmStatus object is equal to valid(1)."
 ::= { alarmEntry 4 }
 alarmValue OBJECT-TYPE
 SYNTAX INTEGER
 ACCESS read-only
 STATUS mandatory
 DESCRIPTION
 "The value of the statistic during the last sampling
 period. For example, if the sample type is
 deltaValue, this value will be the difference
 between the samples at the beginning and end of the
 period. If the sample type is absoluteValue, this
 value will be the sampled value at the end of the
 period.
 This is the value that is compared with the rising and
 falling thresholds.
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RFC 1757 Remote Network Monitoring MIB February 1995
 The value during the current sampling period is not
 made available until the period is completed and will
 remain available until the next period completes."
 ::= { alarmEntry 5 }
 alarmStartupAlarm OBJECT-TYPE
 SYNTAX INTEGER {
 risingAlarm(1),
 fallingAlarm(2),
 risingOrFallingAlarm(3)
 }
 ACCESS read-write
 STATUS mandatory
 DESCRIPTION
 "The alarm that may be sent when this entry is first
 set to valid. If the first sample after this entry
 becomes valid is greater than or equal to the
 risingThreshold and alarmStartupAlarm is equal to
 risingAlarm(1) or risingOrFallingAlarm(3), then a
 single rising alarm will be generated. If the first
 sample after this entry becomes valid is less than
 or equal to the fallingThreshold and
 alarmStartupAlarm is equal to fallingAlarm(2) or
 risingOrFallingAlarm(3), then a single falling alarm
 will be generated.
 This object may not be modified if the associated
 alarmStatus object is equal to valid(1)."
 ::= { alarmEntry 6 }
 alarmRisingThreshold OBJECT-TYPE
 SYNTAX INTEGER
 ACCESS read-write
 STATUS mandatory
 DESCRIPTION
 "A threshold for the sampled statistic. When the
 current sampled value is greater than or equal to
 this threshold, and the value at the last sampling
 interval was less than this threshold, a single
 event will be generated. A single event will also
 be generated if the first sample after this entry
 becomes valid is greater than or equal to this
 threshold and the associated alarmStartupAlarm is
 equal to risingAlarm(1) or risingOrFallingAlarm(3).
 After a rising event is generated, another such event
 will not be generated until the sampled value
 falls below this threshold and reaches the
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RFC 1757 Remote Network Monitoring MIB February 1995
 alarmFallingThreshold.
 This object may not be modified if the associated
 alarmStatus object is equal to valid(1)."
 ::= { alarmEntry 7 }
 alarmFallingThreshold OBJECT-TYPE
 SYNTAX INTEGER
 ACCESS read-write
 STATUS mandatory
 DESCRIPTION
 "A threshold for the sampled statistic. When the
 current sampled value is less than or equal to this
 threshold, and the value at the last sampling
 interval was greater than this threshold, a single
 event will be generated. A single event will also
 be generated if the first sample after this entry
 becomes valid is less than or equal to this
 threshold and the associated alarmStartupAlarm is
 equal to fallingAlarm(2) or risingOrFallingAlarm(3).
 After a falling event is generated, another such event
 will not be generated until the sampled value
 rises above this threshold and reaches the
 alarmRisingThreshold.
 This object may not be modified if the associated
 alarmStatus object is equal to valid(1)."
 ::= { alarmEntry 8 }
 alarmRisingEventIndex OBJECT-TYPE
 SYNTAX INTEGER (0..65535)
 ACCESS read-write
 STATUS mandatory
 DESCRIPTION
 "The index of the eventEntry that is
 used when a rising threshold is crossed. The
 eventEntry identified by a particular value of
 this index is the same as identified by the same value
 of the eventIndex object. If there is no
 corresponding entry in the eventTable, then
 no association exists. In particular, if this value
 is zero, no associated event will be generated, as
 zero is not a valid event index.
 This object may not be modified if the associated
 alarmStatus object is equal to valid(1)."
 ::= { alarmEntry 9 }
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RFC 1757 Remote Network Monitoring MIB February 1995
 alarmFallingEventIndex OBJECT-TYPE
 SYNTAX INTEGER (0..65535)
 ACCESS read-write
 STATUS mandatory
 DESCRIPTION
 "The index of the eventEntry that is
 used when a falling threshold is crossed. The
 eventEntry identified by a particular value of
 this index is the same as identified by the same value
 of the eventIndex object. If there is no
 corresponding entry in the eventTable, then
 no association exists. In particular, if this value
 is zero, no associated event will be generated, as
 zero is not a valid event index.
 This object may not be modified if the associated
 alarmStatus object is equal to valid(1)."
 ::= { alarmEntry 10 }
 alarmOwner OBJECT-TYPE
 SYNTAX OwnerString
 ACCESS read-write
 STATUS mandatory
 DESCRIPTION
 "The entity that configured this entry and is
 therefore using the resources assigned to it."
 ::= { alarmEntry 11 }
 alarmStatus OBJECT-TYPE
 SYNTAX EntryStatus
 ACCESS read-write
 STATUS mandatory
 DESCRIPTION
 "The status of this alarm entry."
 ::= { alarmEntry 12 }
 -- The Host Group
 -- Implementation of the Host group is optional.
 --
 -- The host group discovers new hosts on the network by
 -- keeping a list of source and destination MAC Addresses seen
 -- in good packets. For each of these addresses, the host
 -- group keeps a set of statistics. The hostControlTable
 -- controls which interfaces this function is performed on,
 -- and contains some information about the process. On
 -- behalf of each hostControlEntry, data is collected on an
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RFC 1757 Remote Network Monitoring MIB February 1995
 -- interface and placed in both the hostTable and the
 -- hostTimeTable. If the monitoring device finds itself
 -- short of resources, it may delete entries as needed. It
 -- is suggested that the device delete the least recently
 -- used entries first.
 -- The hostTable contains entries for each address
 -- discovered on a particular interface. Each entry
 -- contains statistical data about that host. This table is
 -- indexed by the MAC address of the host, through which a
 -- random access may be achieved.
 -- The hostTimeTable contains data in the same format as the
 -- hostTable, and must contain the same set of hosts, but is
 -- indexed using hostTimeCreationOrder rather than
 -- hostAddress.
 -- The hostTimeCreationOrder is an integer which reflects
 -- the relative order in which a particular entry was
 -- discovered and thus inserted into the table. As this
 -- order, and thus the index, is among those entries
 -- currently in the table, the index for a particular entry
 -- may change if an (earlier) entry is deleted. Thus the
 -- association between hostTimeCreationOrder and
 -- hostTimeEntry may be broken at any time.
 -- The hostTimeTable has two important uses. The first is the
 -- fast download of this potentially large table. Because the
 -- index of this table runs from 1 to the size of the table,
 -- inclusive, its values are predictable. This allows very
 -- efficient packing of variables into SNMP PDU's and allows
 -- a table transfer to have multiple packets outstanding.
 -- These benefits increase transfer rates tremendously.
 -- The second use of the hostTimeTable is the efficient
 -- discovery by the management station of new entries added
 -- to the table. After the management station has downloaded
 -- the entire table, it knows that new entries will be added
 -- immediately after the end of the current table. It can
 -- thus detect new entries there and retrieve them easily.
 -- Because the association between hostTimeCreationOrder and
 -- hostTimeEntry may be broken at any time, the management
 -- station must monitor the related hostControlLastDeleteTime
 -- object. When the management station thus detects a
 -- deletion, it must assume that any such associations have
 --- been broken, and invalidate any it has stored locally.
 -- This includes restarting any download of the
 -- hostTimeTable that may have been in progress, as well as
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RFC 1757 Remote Network Monitoring MIB February 1995
 -- rediscovering the end of the hostTimeTable so that it may
 -- detect new entries. If the management station does not
 -- detect the broken association, it may continue to refer
 -- to a particular host by its creationOrder while
 -- unwittingly retrieving the data associated with another
 -- host entirely. If this happens while downloading the
 -- host table, the management station may fail to download
 -- all of the entries in the table.
 hostControlTable OBJECT-TYPE
 SYNTAX SEQUENCE OF HostControlEntry
 ACCESS not-accessible
 STATUS mandatory
 DESCRIPTION
 "A list of host table control entries."
 ::= { hosts 1 }
 hostControlEntry OBJECT-TYPE
 SYNTAX HostControlEntry
 ACCESS not-accessible
 STATUS mandatory
 DESCRIPTION
 "A list of parameters that set up the discovery of
 hosts on a particular interface and the collection
 of statistics about these hosts. For example, an
 instance of the hostControlTableSize object might be
 named hostControlTableSize.1"
 INDEX { hostControlIndex }
 ::= { hostControlTable 1 }
 HostControlEntry ::= SEQUENCE {
 hostControlIndex INTEGER (1..65535),
 hostControlDataSource OBJECT IDENTIFIER,
 hostControlTableSize INTEGER,
 hostControlLastDeleteTime TimeTicks,
 hostControlOwner OwnerString,
 hostControlStatus EntryStatus
 }
 hostControlIndex OBJECT-TYPE
 SYNTAX INTEGER (1..65535)
 ACCESS read-only
 STATUS mandatory
 DESCRIPTION
 "An index that uniquely identifies an entry in the
 hostControl table. Each such entry defines
 a function that discovers hosts on a particular
 interface and places statistics about them in the
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RFC 1757 Remote Network Monitoring MIB February 1995
 hostTable and the hostTimeTable on behalf of this
 hostControlEntry."
 ::= { hostControlEntry 1 }
 hostControlDataSource OBJECT-TYPE
 SYNTAX OBJECT IDENTIFIER
 ACCESS read-write
 STATUS mandatory
 DESCRIPTION
 "This object identifies the source of the data for
 this instance of the host function. This source
 can be any interface on this device. In order
 to identify a particular interface, this object shall
 identify the instance of the ifIndex object, defined
 in RFC 1213 and RFC 1573 [4,6], for the desired
 interface. For example, if an entry were to receive
 data from interface #1, this object would be set to
 ifIndex.1.
 The statistics in this group reflect all packets
 on the local network segment attached to the
 identified interface.
 An agent may or may not be able to tell if
 fundamental changes to the media of the interface
 have occurred and necessitate an invalidation of
 this entry. For example, a hot-pluggable ethernet
 card could be pulled out and replaced by a
 token-ring card. In such a case, if the agent has
 such knowledge of the change, it is recommended that
 it invalidate this entry.
 This object may not be modified if the associated
 hostControlStatus object is equal to valid(1)."
 ::= { hostControlEntry 2 }
 hostControlTableSize OBJECT-TYPE
 SYNTAX INTEGER
 ACCESS read-only
 STATUS mandatory
 DESCRIPTION
 "The number of hostEntries in the hostTable and the
 hostTimeTable associated with this hostControlEntry."
 ::= { hostControlEntry 3 }
 hostControlLastDeleteTime OBJECT-TYPE
 SYNTAX TimeTicks
 ACCESS read-only
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RFC 1757 Remote Network Monitoring MIB February 1995
 STATUS mandatory
 DESCRIPTION
 "The value of sysUpTime when the last entry
 was deleted from the portion of the hostTable
 associated with this hostControlEntry. If no
 deletions have occurred, this value shall be zero."
 ::= { hostControlEntry 4 }
 hostControlOwner OBJECT-TYPE
 SYNTAX OwnerString
 ACCESS read-write
 STATUS mandatory
 DESCRIPTION
 "The entity that configured this entry and is
 therefore using the resources assigned to it."
 ::= { hostControlEntry 5 }
 hostControlStatus OBJECT-TYPE
 SYNTAX EntryStatus
 ACCESS read-write
 STATUS mandatory
 DESCRIPTION
 "The status of this hostControl entry.
 If this object is not equal to valid(1), all
 associated entries in the hostTable, hostTimeTable,
 and the hostTopNTable shall be deleted by the
 agent."
 ::= { hostControlEntry 6 }
 hostTable OBJECT-TYPE
 SYNTAX SEQUENCE OF HostEntry
 ACCESS not-accessible
 STATUS mandatory
 DESCRIPTION
 "A list of host entries."
 ::= { hosts 2 }
 hostEntry OBJECT-TYPE
 SYNTAX HostEntry
 ACCESS not-accessible
 STATUS mandatory
 DESCRIPTION
 "A collection of statistics for a particular host
 that has been discovered on an interface of this
 device. For example, an instance of the
 hostOutBroadcastPkts object might be named
 hostOutBroadcastPkts.1.6.8.0.32.27.3.176"
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RFC 1757 Remote Network Monitoring MIB February 1995
 INDEX { hostIndex, hostAddress }
 ::= { hostTable 1 }
 HostEntry ::= SEQUENCE {
 hostAddress OCTET STRING,
 hostCreationOrder INTEGER (1..65535),
 hostIndex INTEGER (1..65535),
 hostInPkts Counter,
 hostOutPkts Counter,
 hostInOctets Counter,
 hostOutOctets Counter,
 hostOutErrors Counter,
 hostOutBroadcastPkts Counter,
 hostOutMulticastPkts Counter
 }
 hostAddress OBJECT-TYPE
 SYNTAX OCTET STRING
 ACCESS read-only
 STATUS mandatory
 DESCRIPTION
 "The physical address of this host."
 ::= { hostEntry 1 }
 hostCreationOrder OBJECT-TYPE
 SYNTAX INTEGER (1..65535)
 ACCESS read-only
 STATUS mandatory
 DESCRIPTION
 "An index that defines the relative ordering of
 the creation time of hosts captured for a
 particular hostControlEntry. This index shall
 be between 1 and N, where N is the value of
 the associated hostControlTableSize. The ordering
 of the indexes is based on the order of each entry's
 insertion into the table, in which entries added
 earlier have a lower index value than entries added
 later.
 It is important to note that the order for a
 particular entry may change as an (earlier) entry
 is deleted from the table. Because this order may
 change, management stations should make use of the
 hostControlLastDeleteTime variable in the
 hostControlEntry associated with the relevant
 portion of the hostTable. By observing
 this variable, the management station may detect
 the circumstances where a previous association
Waldbusser [Page 43]

RFC 1757 Remote Network Monitoring MIB February 1995
 between a value of hostCreationOrder
 and a hostEntry may no longer hold."
 ::= { hostEntry 2 }
 hostIndex OBJECT-TYPE
 SYNTAX INTEGER (1..65535)
 ACCESS read-only
 STATUS mandatory
 DESCRIPTION
 "The set of collected host statistics of which
 this entry is a part. The set of hosts
 identified by a particular value of this
 index is associated with the hostControlEntry
 as identified by the same value of hostControlIndex."
 ::= { hostEntry 3 }
 hostInPkts OBJECT-TYPE
 SYNTAX Counter
 ACCESS read-only
 STATUS mandatory
 DESCRIPTION
 "The number of good packets transmitted to this
 address since it was added to the hostTable."
 ::= { hostEntry 4 }
 hostOutPkts OBJECT-TYPE
 SYNTAX Counter
 ACCESS read-only
 STATUS mandatory
 DESCRIPTION
 "The number of packets, including bad packets,
 transmitted by this address since it was added
 to the hostTable."
 ::= { hostEntry 5 }
 hostInOctets OBJECT-TYPE
 SYNTAX Counter
 ACCESS read-only
 STATUS mandatory
 DESCRIPTION
 "The number of octets transmitted to this address
 since it was added to the hostTable (excluding
 framing bits but including FCS octets), except for
 those octets in bad packets."
 ::= { hostEntry 6 }
 hostOutOctets OBJECT-TYPE
 SYNTAX Counter
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RFC 1757 Remote Network Monitoring MIB February 1995
 ACCESS read-only
 STATUS mandatory
 DESCRIPTION
 "The number of octets transmitted by this address
 since it was added to the hostTable (excluding
 framing bits but including FCS octets), including
 those octets in bad packets."
 ::= { hostEntry 7 }
 hostOutErrors OBJECT-TYPE
 SYNTAX Counter
 ACCESS read-only
 STATUS mandatory
 DESCRIPTION
 "The number of bad packets transmitted by this address
 since this host was added to the hostTable."
 ::= { hostEntry 8 }
 hostOutBroadcastPkts OBJECT-TYPE
 SYNTAX Counter
 ACCESS read-only
 STATUS mandatory
 DESCRIPTION
 "The number of good packets transmitted by this
 address that were directed to the broadcast address
 since this host was added to the hostTable."
 ::= { hostEntry 9 }
 hostOutMulticastPkts OBJECT-TYPE
 SYNTAX Counter
 ACCESS read-only
 STATUS mandatory
 DESCRIPTION
 "The number of good packets transmitted by this
 address that were directed to a multicast address
 since this host was added to the hostTable.
 Note that this number does not include packets
 directed to the broadcast address."
 ::= { hostEntry 10 }
 -- host Time Table
 hostTimeTable OBJECT-TYPE
 SYNTAX SEQUENCE OF HostTimeEntry
 ACCESS not-accessible
 STATUS mandatory
 DESCRIPTION
 "A list of time-ordered host table entries."
Waldbusser [Page 45]

RFC 1757 Remote Network Monitoring MIB February 1995
 ::= { hosts 3 }
 hostTimeEntry OBJECT-TYPE
 SYNTAX HostTimeEntry
 ACCESS not-accessible
 STATUS mandatory
 DESCRIPTION
 "A collection of statistics for a particular host
 that has been discovered on an interface of this
 device. This collection includes the relative
 ordering of the creation time of this object. For
 example, an instance of the hostTimeOutBroadcastPkts
 object might be named
 hostTimeOutBroadcastPkts.1.687"
 INDEX { hostTimeIndex, hostTimeCreationOrder }
 ::= { hostTimeTable 1 }
 HostTimeEntry ::= SEQUENCE {
 hostTimeAddress OCTET STRING,
 hostTimeCreationOrder INTEGER (1..65535),
 hostTimeIndex INTEGER (1..65535),
 hostTimeInPkts Counter,
 hostTimeOutPkts Counter,
 hostTimeInOctets Counter,
 hostTimeOutOctets Counter,
 hostTimeOutErrors Counter,
 hostTimeOutBroadcastPkts Counter,
 hostTimeOutMulticastPkts Counter
 }
 hostTimeAddress OBJECT-TYPE
 SYNTAX OCTET STRING
 ACCESS read-only
 STATUS mandatory
 DESCRIPTION
 "The physical address of this host."
 ::= { hostTimeEntry 1 }
 hostTimeCreationOrder OBJECT-TYPE
 SYNTAX INTEGER (1..65535)
 ACCESS read-only
 STATUS mandatory
 DESCRIPTION
 "An index that uniquely identifies an entry in
 the hostTime table among those entries associated
 with the same hostControlEntry. This index shall
 be between 1 and N, where N is the value of
 the associated hostControlTableSize. The ordering
Waldbusser [Page 46]

RFC 1757 Remote Network Monitoring MIB February 1995
 of the indexes is based on the order of each entry's
 insertion into the table, in which entries added
 earlier have a lower index value than entries added
 later. Thus the management station has the ability to
 learn of new entries added to this table without
 downloading the entire table.
 It is important to note that the index for a
 particular entry may change as an (earlier) entry
 is deleted from the table. Because this order may
 change, management stations should make use of the
 hostControlLastDeleteTime variable in the
 hostControlEntry associated with the relevant
 portion of the hostTimeTable. By observing
 this variable, the management station may detect
 the circumstances where a download of the table
 may have missed entries, and where a previous
 association between a value of hostTimeCreationOrder
 and a hostTimeEntry may no longer hold."
 ::= { hostTimeEntry 2 }
 hostTimeIndex OBJECT-TYPE
 SYNTAX INTEGER (1..65535)
 ACCESS read-only
 STATUS mandatory
 DESCRIPTION
 "The set of collected host statistics of which
 this entry is a part. The set of hosts
 identified by a particular value of this
 index is associated with the hostControlEntry
 as identified by the same value of hostControlIndex."
 ::= { hostTimeEntry 3 }
 hostTimeInPkts OBJECT-TYPE
 SYNTAX Counter
 ACCESS read-only
 STATUS mandatory
 DESCRIPTION
 "The number of good packets transmitted to this
 address since it was added to the hostTimeTable."
 ::= { hostTimeEntry 4 }
 hostTimeOutPkts OBJECT-TYPE
 SYNTAX Counter
 ACCESS read-only
 STATUS mandatory
 DESCRIPTION
 "The number of god packets transmitted by this
Waldbusser [Page 47]

RFC 1757 Remote Network Monitoring MIB February 1995
 address since it was added to the hostTimeTable."
 ::= { hostTimeEntry 5 }
 hostTimeInOctets OBJECT-TYPE
 SYNTAX Counter
 ACCESS read-only
 STATUS mandatory
 DESCRIPTION
 "The number of octets transmitted to this address
 since it was added to the hostTimeTable (excluding
 framing bits but including FCS octets), except for
 those octets in bad packets."
 ::= { hostTimeEntry 6 }
 hostTimeOutOctets OBJECT-TYPE
 SYNTAX Counter
 ACCESS read-only
 STATUS mandatory
 DESCRIPTION
 "The number of octets transmitted by this address
 since it was added to the hostTimeTable (excluding
 framing bits but including FCS octets), including
 those octets in bad packets."
 ::= { hostTimeEntry 7 }
 hostTimeOutErrors OBJECT-TYPE
 SYNTAX Counter
 ACCESS read-only
 STATUS mandatory
 DESCRIPTION
 "The number of bad packets transmitted by this address
 since this host was added to the hostTimeTable."
 ::= { hostTimeEntry 8 }
 hostTimeOutBroadcastPkts OBJECT-TYPE
 SYNTAX Counter
 ACCESS read-only
 STATUS mandatory
 DESCRIPTION
 "The number of good packets transmitted by this
 address that were directed to the broadcast address
 since this host was added to the hostTimeTable."
 ::= { hostTimeEntry 9 }
 hostTimeOutMulticastPkts OBJECT-TYPE
 SYNTAX Counter
 ACCESS read-only
 STATUS mandatory
Waldbusser [Page 48]

RFC 1757 Remote Network Monitoring MIB February 1995
 DESCRIPTION
 "The number of good packets transmitted by this
 address that were directed to a multicast address
 since this host was added to the hostTimeTable.
 Note that this number does not include packets
 directed to the broadcast address."
 ::= { hostTimeEntry 10 }
 -- The Host Top "N" Group
 -- Implementation of the Host Top N group is optional.
 --
 -- The Host Top N group requires the implementation of the
 -- host group.
 --
 -- The Host Top N group is used to prepare reports that
 -- describe the hosts that top a list ordered by one of
 -- their statistics.
 -- The available statistics are samples of one of their
 -- base statistics, over an interval specified by the
 -- management station. Thus, these statistics are rate
 -- based. The management station also selects how many such
 -- hosts are reported.
 -- The hostTopNControlTable is used to initiate the
 -- generation of such a report. The management station
 -- may select the parameters of such a report, such as
 -- which interface, which statistic, how many hosts,
 -- and the start and stop times of the sampling. When
 -- the report is prepared, entries are created in the
 -- hostTopNTable associated with the relevant
 -- hostTopNControlEntry. These entries are static for
 -- each report after it has been prepared.
 hostTopNControlTable OBJECT-TYPE
 SYNTAX SEQUENCE OF HostTopNControlEntry
 ACCESS not-accessible
 STATUS mandatory
 DESCRIPTION
 "A list of top N host control entries."
 ::= { hostTopN 1 }
 hostTopNControlEntry OBJECT-TYPE
 SYNTAX HostTopNControlEntry
 ACCESS not-accessible
 STATUS mandatory
 DESCRIPTION
Waldbusser [Page 49]

RFC 1757 Remote Network Monitoring MIB February 1995
 "A set of parameters that control the creation of a
 report of the top N hosts according to several
 metrics. For example, an instance of the
 hostTopNDuration object might be named
 hostTopNDuration.3"
 INDEX { hostTopNControlIndex }
 ::= { hostTopNControlTable 1 }
 HostTopNControlEntry ::= SEQUENCE {
 hostTopNControlIndex INTEGER (1..65535),
 hostTopNHostIndex INTEGER (1..65535),
 hostTopNRateBase INTEGER,
 hostTopNTimeRemaining INTEGER,
 hostTopNDuration INTEGER,
 hostTopNRequestedSize INTEGER,
 hostTopNGrantedSize INTEGER,
 hostTopNStartTime TimeTicks,
 hostTopNOwner OwnerString,
 hostTopNStatus EntryStatus
 }
 hostTopNControlIndex OBJECT-TYPE
 SYNTAX INTEGER (1..65535)
 ACCESS read-only
 STATUS mandatory
 DESCRIPTION
 "An index that uniquely identifies an entry
 in the hostTopNControl table. Each such
 entry defines one top N report prepared for
 one interface."
 ::= { hostTopNControlEntry 1 }
 hostTopNHostIndex OBJECT-TYPE
 SYNTAX INTEGER (1..65535)
 ACCESS read-write
 STATUS mandatory
 DESCRIPTION
 "The host table for which a top N report will be
 prepared on behalf of this entry. The host table
 identified by a particular value of this index is
 associated with the same host table as identified by
 the same value of hostIndex.
 This object may not be modified if the associated
 hostTopNStatus object is equal to valid(1)."
 ::= { hostTopNControlEntry 2 }
 hostTopNRateBase OBJECT-TYPE
Waldbusser [Page 50]

RFC 1757 Remote Network Monitoring MIB February 1995
 SYNTAX INTEGER {
 hostTopNInPkts(1),
 hostTopNOutPkts(2),
 hostTopNInOctets(3),
 hostTopNOutOctets(4),
 hostTopNOutErrors(5),
 hostTopNOutBroadcastPkts(6),
 hostTopNOutMulticastPkts(7)
 }
 ACCESS read-write
 STATUS mandatory
 DESCRIPTION
 "The variable for each host that the hostTopNRate
 variable is based upon.
 This object may not be modified if the associated
 hostTopNStatus object is equal to valid(1)."
 ::= { hostTopNControlEntry 3 }
 hostTopNTimeRemaining OBJECT-TYPE
 SYNTAX INTEGER
 ACCESS read-write
 STATUS mandatory
 DESCRIPTION
 "The number of seconds left in the report currently
 being collected. When this object is modified by
 the management station, a new collection is started,
 possibly aborting a currently running report. The
 new value is used as the requested duration of this
 report, which is loaded into the associated
 hostTopNDuration object.
 When this object is set to a non-zero value, any
 associated hostTopNEntries shall be made
 inaccessible by the monitor. While the value of
 this object is non-zero, it decrements by one per
 second until it reaches zero. During this time, all
 associated hostTopNEntries shall remain
 inaccessible. At the time that this object
 decrements to zero, the report is made accessible in
 the hostTopNTable. Thus, the hostTopN table needs
 to be created only at the end of the collection
 interval."
 DEFVAL { 0 }
 ::= { hostTopNControlEntry 4 }
 hostTopNDuration OBJECT-TYPE
 SYNTAX INTEGER
Waldbusser [Page 51]

RFC 1757 Remote Network Monitoring MIB February 1995
 ACCESS read-only
 STATUS mandatory
 DESCRIPTION
 "The number of seconds that this report has collected
 during the last sampling interval, or if this
 report is currently being collected, the number
 of seconds that this report is being collected
 during this sampling interval.
 When the associated hostTopNTimeRemaining object is
 set, this object shall be set by the probe to the
 same value and shall not be modified until the next
 time the hostTopNTimeRemaining is set.
 This value shall be zero if no reports have been
 requested for this hostTopNControlEntry."
 DEFVAL { 0 }
 ::= { hostTopNControlEntry 5 }
 hostTopNRequestedSize OBJECT-TYPE
 SYNTAX INTEGER
 ACCESS read-write
 STATUS mandatory
 DESCRIPTION
 "The maximum number of hosts requested for the top N
 table.
 When this object is created or modified, the probe
 should set hostTopNGrantedSize as closely to this
 object as is possible for the particular probe
 implementation and available resources."
 DEFVAL { 10 }
 ::= { hostTopNControlEntry 6 }
 hostTopNGrantedSize OBJECT-TYPE
 SYNTAX INTEGER
 ACCESS read-only
 STATUS mandatory
 DESCRIPTION
 "The maximum number of hosts in the top N table.
 When the associated hostTopNRequestedSize object is
 created or modified, the probe should set this
 object as closely to the requested value as is
 possible for the particular implementation and
 available resources. The probe must not lower this
 value except as a result of a set to the associated
 hostTopNRequestedSize object.
Waldbusser [Page 52]

RFC 1757 Remote Network Monitoring MIB February 1995
 Hosts with the highest value of hostTopNRate shall be
 placed in this table in decreasing order of this rate
 until there is no more room or until there are no more
 hosts."
 ::= { hostTopNControlEntry 7 }
 hostTopNStartTime OBJECT-TYPE
 SYNTAX TimeTicks
 ACCESS read-only
 STATUS mandatory
 DESCRIPTION
 "The value of sysUpTime when this top N report was
 last started. In other words, this is the time that
 the associated hostTopNTimeRemaining object was
 modified to start the requested report."
 ::= { hostTopNControlEntry 8 }
 hostTopNOwner OBJECT-TYPE
 SYNTAX OwnerString
 ACCESS read-write
 STATUS mandatory
 DESCRIPTION
 "The entity that configured this entry and is
 therefore using the resources assigned to it."
 ::= { hostTopNControlEntry 9 }
 hostTopNStatus OBJECT-TYPE
 SYNTAX EntryStatus
 ACCESS read-write
 STATUS mandatory
 DESCRIPTION
 "The status of this hostTopNControl entry.
 If this object is not equal to valid(1), all
 associated hostTopNEntries shall be deleted by the
 agent."
 ::= { hostTopNControlEntry 10 }
 hostTopNTable OBJECT-TYPE
 SYNTAX SEQUENCE OF HostTopNEntry
 ACCESS not-accessible
 STATUS mandatory
 DESCRIPTION
 "A list of top N host entries."
 ::= { hostTopN 2 }
 hostTopNEntry OBJECT-TYPE
 SYNTAX HostTopNEntry
Waldbusser [Page 53]

RFC 1757 Remote Network Monitoring MIB February 1995
 ACCESS not-accessible
 STATUS mandatory
 DESCRIPTION
 "A set of statistics for a host that is part of a
 top N report. For example, an instance of the
 hostTopNRate object might be named
 hostTopNRate.3.10"
 INDEX { hostTopNReport, hostTopNIndex }
 ::= { hostTopNTable 1 }
 HostTopNEntry ::= SEQUENCE {
 hostTopNReport INTEGER (1..65535),
 hostTopNIndex INTEGER (1..65535),
 hostTopNAddress OCTET STRING,
 hostTopNRate INTEGER
 }
 hostTopNReport OBJECT-TYPE
 SYNTAX INTEGER (1..65535)
 ACCESS read-only
 STATUS mandatory
 DESCRIPTION
 "This object identifies the top N report of which
 this entry is a part. The set of hosts
 identified by a particular value of this
 object is part of the same report as identified
 by the same value of the hostTopNControlIndex object."
 ::= { hostTopNEntry 1 }
 hostTopNIndex OBJECT-TYPE
 SYNTAX INTEGER (1..65535)
 ACCESS read-only
 STATUS mandatory
 DESCRIPTION
 "An index that uniquely identifies an entry in
 the hostTopN table among those in the same report.
 This index is between 1 and N, where N is the
 number of entries in this table. Increasing values
 of hostTopNIndex shall be assigned to entries with
 decreasing values of hostTopNRate until index N
 is assigned to the entry with the lowest value of
 hostTopNRate or there are no more hostTopNEntries."
 ::= { hostTopNEntry 2 }
 hostTopNAddress OBJECT-TYPE
 SYNTAX OCTET STRING
 ACCESS read-only
 STATUS mandatory
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RFC 1757 Remote Network Monitoring MIB February 1995
 DESCRIPTION
 "The physical address of this host."
 ::= { hostTopNEntry 3 }
 hostTopNRate OBJECT-TYPE
 SYNTAX INTEGER
 ACCESS read-only
 STATUS mandatory
 DESCRIPTION
 "The amount of change in the selected variable
 during this sampling interval. The selected
 variable is this host's instance of the object
 selected by hostTopNRateBase."
 ::= { hostTopNEntry 4 }
 -- The Matrix Group
 -- Implementation of the Matrix group is optional.
 --
 -- The Matrix group consists of the matrixControlTable,
 -- matrixSDTable and the matrixDSTable. These tables
 -- store statistics for a particular conversation
 -- between two addresses. As the device detects a new
 -- conversation, including those to a non-unicast
 -- address, it creates a new entry in both of the
 -- matrix tables. It must only create new entries
 -- based on information received in good packets. If
 -- the monitoring device finds itself short of
 -- resources, it may delete entries as needed. It is
 -- suggested that the device delete the least recently
 -- used entries first.
 matrixControlTable OBJECT-TYPE
 SYNTAX SEQUENCE OF MatrixControlEntry
 ACCESS not-accessible
 STATUS mandatory
 DESCRIPTION
 "A list of information entries for the
 traffic matrix on each interface."
 ::= { matrix 1 }
 matrixControlEntry OBJECT-TYPE
 SYNTAX MatrixControlEntry
 ACCESS not-accessible
 STATUS mandatory
 DESCRIPTION
 "Information about a traffic matrix on a particular
Waldbusser [Page 55]

RFC 1757 Remote Network Monitoring MIB February 1995
 interface. For example, an instance of the
 matrixControlLastDeleteTime object might be named
 matrixControlLastDeleteTime.1"
 INDEX { matrixControlIndex }
 ::= { matrixControlTable 1 }
 MatrixControlEntry ::= SEQUENCE {
 matrixControlIndex INTEGER (1..65535),
 matrixControlDataSource OBJECT IDENTIFIER,
 matrixControlTableSize INTEGER,
 matrixControlLastDeleteTime TimeTicks,
 matrixControlOwner OwnerString,
 matrixControlStatus EntryStatus
 }
 matrixControlIndex OBJECT-TYPE
 SYNTAX INTEGER (1..65535)
 ACCESS read-only
 STATUS mandatory
 DESCRIPTION
 "An index that uniquely identifies an entry in the
 matrixControl table. Each such entry defines
 a function that discovers conversations on a
 particular interface and places statistics about
 them in the matrixSDTable and the matrixDSTable on
 behalf of this matrixControlEntry."
 ::= { matrixControlEntry 1 }
 matrixControlDataSource OBJECT-TYPE
 SYNTAX OBJECT IDENTIFIER
 ACCESS read-write
 STATUS mandatory
 DESCRIPTION
 "This object identifies the source of
 the data from which this entry creates a traffic
 matrix. This source can be any interface on this
 device. In order to identify a particular
 interface, this object shall identify the instance
 of the ifIndex object, defined in RFC 1213 and RFC
 1573 [4,6], for the desired interface. For example,
 if an entry were to receive data from interface #1,
 this object would be set to ifIndex.1.
 The statistics in this group reflect all packets
 on the local network segment attached to the
 identified interface.
 An agent may or may not be able to tell if
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RFC 1757 Remote Network Monitoring MIB February 1995
 fundamental changes to the media of the interface
 have occurred and necessitate an invalidation of
 this entry. For example, a hot-pluggable ethernet
 card could be pulled out and replaced by a
 token-ring card. In such a case, if the agent has
 such knowledge of the change, it is recommended that
 it invalidate this entry.
 This object may not be modified if the associated
 matrixControlStatus object is equal to valid(1)."
 ::= { matrixControlEntry 2 }
 matrixControlTableSize OBJECT-TYPE
 SYNTAX INTEGER
 ACCESS read-only
 STATUS mandatory
 DESCRIPTION
 "The number of matrixSDEntries in the matrixSDTable
 for this interface. This must also be the value of
 the number of entries in the matrixDSTable for this
 interface."
 ::= { matrixControlEntry 3 }
 matrixControlLastDeleteTime OBJECT-TYPE
 SYNTAX TimeTicks
 ACCESS read-only
 STATUS mandatory
 DESCRIPTION
 "The value of sysUpTime when the last entry
 was deleted from the portion of the matrixSDTable
 or matrixDSTable associated with this
 matrixControlEntry. If no deletions have occurred,
 this value shall be zero."
 ::= { matrixControlEntry 4 }
 matrixControlOwner OBJECT-TYPE
 SYNTAX OwnerString
 ACCESS read-write
 STATUS mandatory
 DESCRIPTION
 "The entity that configured this entry and is
 therefore using the resources assigned to it."
 ::= { matrixControlEntry 5 }
 matrixControlStatus OBJECT-TYPE
 SYNTAX EntryStatus
 ACCESS read-write
 STATUS mandatory
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RFC 1757 Remote Network Monitoring MIB February 1995
 DESCRIPTION
 "The status of this matrixControl entry.
 If this object is not equal to valid(1), all
 associated entries in the matrixSDTable and the
 matrixDSTable shall be deleted by the agent."
 ::= { matrixControlEntry 6 }
 matrixSDTable OBJECT-TYPE
 SYNTAX SEQUENCE OF MatrixSDEntry
 ACCESS not-accessible
 STATUS mandatory
 DESCRIPTION
 "A list of traffic matrix entries indexed by
 source and destination MAC address."
 ::= { matrix 2 }
 matrixSDEntry OBJECT-TYPE
 SYNTAX MatrixSDEntry
 ACCESS not-accessible
 STATUS mandatory
 DESCRIPTION
 "A collection of statistics for communications between
 two addresses on a particular interface. For example,
 an instance of the matrixSDPkts object might be named
 matrixSDPkts.1.6.8.0.32.27.3.176.6.8.0.32.10.8.113"
 INDEX { matrixSDIndex,
 matrixSDSourceAddress, matrixSDDestAddress }
 ::= { matrixSDTable 1 }
 MatrixSDEntry ::= SEQUENCE {
 matrixSDSourceAddress OCTET STRING,
 matrixSDDestAddress OCTET STRING,
 matrixSDIndex INTEGER (1..65535),
 matrixSDPkts Counter,
 matrixSDOctets Counter,
 matrixSDErrors Counter
 }
 matrixSDSourceAddress OBJECT-TYPE
 SYNTAX OCTET STRING
 ACCESS read-only
 STATUS mandatory
 DESCRIPTION
 "The source physical address."
 ::= { matrixSDEntry 1 }
 matrixSDDestAddress OBJECT-TYPE
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RFC 1757 Remote Network Monitoring MIB February 1995
 SYNTAX OCTET STRING
 ACCESS read-only
 STATUS mandatory
 DESCRIPTION
 "The destination physical address."
 ::= { matrixSDEntry 2 }
 matrixSDIndex OBJECT-TYPE
 SYNTAX INTEGER (1..65535)
 ACCESS read-only
 STATUS mandatory
 DESCRIPTION
 "The set of collected matrix statistics of which
 this entry is a part. The set of matrix statistics
 identified by a particular value of this index
 is associated with the same matrixControlEntry
 as identified by the same value of
 matrixControlIndex."
 ::= { matrixSDEntry 3 }
 matrixSDPkts OBJECT-TYPE
 SYNTAX Counter
 ACCESS read-only
 STATUS mandatory
 DESCRIPTION
 "The number of packets transmitted from the source
 address to the destination address (this number
 includes bad packets)."
 ::= { matrixSDEntry 4 }
 matrixSDOctets OBJECT-TYPE
 SYNTAX Counter
 ACCESS read-only
 STATUS mandatory
 DESCRIPTION
 "The number of octets (excluding framing bits but
 including FCS octets) contained in all packets
 transmitted from the source address to the
 destination address."
 ::= { matrixSDEntry 5 }
 matrixSDErrors OBJECT-TYPE
 SYNTAX Counter
 ACCESS read-only
 STATUS mandatory
 DESCRIPTION
 "The number of bad packets transmitted from
 the source address to the destination address."
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RFC 1757 Remote Network Monitoring MIB February 1995
 ::= { matrixSDEntry 6 }
 -- Traffic matrix tables from destination to source
 matrixDSTable OBJECT-TYPE
 SYNTAX SEQUENCE OF MatrixDSEntry
 ACCESS not-accessible
 STATUS mandatory
 DESCRIPTION
 "A list of traffic matrix entries indexed by
 destination and source MAC address."
 ::= { matrix 3 }
 matrixDSEntry OBJECT-TYPE
 SYNTAX MatrixDSEntry
 ACCESS not-accessible
 STATUS mandatory
 DESCRIPTION
 "A collection of statistics for communications between
 two addresses on a particular interface. For example,
 an instance of the matrixSDPkts object might be named
 matrixSDPkts.1.6.8.0.32.10.8.113.6.8.0.32.27.3.176"
 INDEX { matrixDSIndex,
 matrixDSDestAddress, matrixDSSourceAddress }
 ::= { matrixDSTable 1 }
 MatrixDSEntry ::= SEQUENCE {
 matrixDSSourceAddress OCTET STRING,
 matrixDSDestAddress OCTET STRING,
 matrixDSIndex INTEGER (1..65535),
 matrixDSPkts Counter,
 matrixDSOctets Counter,
 matrixDSErrors Counter
 }
 matrixDSSourceAddress OBJECT-TYPE
 SYNTAX OCTET STRING
 ACCESS read-only
 STATUS mandatory
 DESCRIPTION
 "The source physical address."
 ::= { matrixDSEntry 1 }
 matrixDSDestAddress OBJECT-TYPE
 SYNTAX OCTET STRING
 ACCESS read-only
 STATUS mandatory
Waldbusser [Page 60]

RFC 1757 Remote Network Monitoring MIB February 1995
 DESCRIPTION
 "The destination physical address."
 ::= { matrixDSEntry 2 }
 matrixDSIndex OBJECT-TYPE
 SYNTAX INTEGER (1..65535)
 ACCESS read-only
 STATUS mandatory
 DESCRIPTION
 "The set of collected matrix statistics of which
 this entry is a part. The set of matrix statistics
 identified by a particular value of this index
 is associated with the same matrixControlEntry
 as identified by the same value of
 matrixControlIndex."
 ::= { matrixDSEntry 3 }
 matrixDSPkts OBJECT-TYPE
 SYNTAX Counter
 ACCESS read-only
 STATUS mandatory
 DESCRIPTION
 "The number of packets transmitted from the source
 address to the destination address (this number
 includes bad packets)."
 ::= { matrixDSEntry 4 }
 matrixDSOctets OBJECT-TYPE
 SYNTAX Counter
 ACCESS read-only
 STATUS mandatory
 DESCRIPTION
 "The number of octets (excluding framing bits
 but including FCS octets) contained in all packets
 transmitted from the source address to the
 destination address."
 ::= { matrixDSEntry 5 }
 matrixDSErrors OBJECT-TYPE
 SYNTAX Counter
 ACCESS read-only
 STATUS mandatory
 DESCRIPTION
 "The number of bad packets transmitted from
 the source address to the destination address."
 ::= { matrixDSEntry 6 }
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RFC 1757 Remote Network Monitoring MIB February 1995
 -- The Filter Group
 -- Implementation of the Filter group is optional.
 --
 -- The Filter group allows packets to be captured with an
 -- arbitrary filter expression. A logical data and
 -- event stream or "channel" is formed by the packets
 -- that match the filter expression.
 --
 -- This filter mechanism allows the creation of an arbitrary
 -- logical expression with which to filter packets. Each
 -- filter associated with a channel is OR'ed with the others.
 -- Within a filter, any bits checked in the data and status
 -- are AND'ed with respect to other bits in the same filter.
 -- The NotMask also allows for checking for inequality.
 -- Finally, the channelAcceptType object allows for
 -- inversion of the whole equation.
 --
 -- If a management station wishes to receive a trap to alert
 -- it that new packets have been captured and are available
 -- for download, it is recommended that it set up an alarm
 -- entry that monitors the value of the relevant
 -- channelMatches instance.
 --
 -- The channel can be turned on or off, and can also
 -- generate events when packets pass through it.
 filterTable OBJECT-TYPE
 SYNTAX SEQUENCE OF FilterEntry
 ACCESS not-accessible
 STATUS mandatory
 DESCRIPTION
 "A list of packet filter entries."
 ::= { filter 1 }
 filterEntry OBJECT-TYPE
 SYNTAX FilterEntry
 ACCESS not-accessible
 STATUS mandatory
 DESCRIPTION
 "A set of parameters for a packet filter applied on a
 particular interface. As an example, an instance of
 the filterPktData object might be named
 filterPktData.12"
 INDEX { filterIndex }
 ::= { filterTable 1 }
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RFC 1757 Remote Network Monitoring MIB February 1995
 FilterEntry ::= SEQUENCE {
 filterIndex INTEGER (1..65535),
 filterChannelIndex INTEGER (1..65535),
 filterPktDataOffset INTEGER,
 filterPktData OCTET STRING,
 filterPktDataMask OCTET STRING,
 filterPktDataNotMask OCTET STRING,
 filterPktStatus INTEGER,
 filterPktStatusMask INTEGER,
 filterPktStatusNotMask INTEGER,
 filterOwner OwnerString,
 filterStatus EntryStatus
 }
 filterIndex OBJECT-TYPE
 SYNTAX INTEGER (1..65535)
 ACCESS read-only
 STATUS mandatory
 DESCRIPTION
 "An index that uniquely identifies an entry
 in the filter table. Each such entry defines
 one filter that is to be applied to every packet
 received on an interface."
 ::= { filterEntry 1 }
 filterChannelIndex OBJECT-TYPE
 SYNTAX INTEGER (1..65535)
 ACCESS read-write
 STATUS mandatory
 DESCRIPTION
 "This object identifies the channel of which this
 filter is a part. The filters identified by a
 particular value of this object are associated with
 the same channel as identified by the same value of
 the channelIndex object."
 ::= { filterEntry 2 }
 filterPktDataOffset OBJECT-TYPE
 SYNTAX INTEGER
 ACCESS read-write
 STATUS mandatory
 DESCRIPTION
 "The offset from the beginning of each packet where
 a match of packet data will be attempted. This offset
 is measured from the point in the physical layer
 packet after the framing bits, if any. For example,
 in an Ethernet frame, this point is at the beginning
 of the destination MAC address.
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RFC 1757 Remote Network Monitoring MIB February 1995
 This object may not be modified if the associated
 filterStatus object is equal to valid(1)."
 DEFVAL { 0 }
 ::= { filterEntry 3 }
 filterPktData OBJECT-TYPE
 SYNTAX OCTET STRING
 ACCESS read-write
 STATUS mandatory
 DESCRIPTION
 "The data that is to be matched with the input
 packet. For each packet received, this filter and
 the accompanying filterPktDataMask and
 filterPktDataNotMask will be adjusted for the
 offset. The only bits relevant to this match
 algorithm are those that have the corresponding
 filterPktDataMask bit equal to one. The following
 three rules are then applied to every packet:
 (1) If the packet is too short and does not have data
 corresponding to part of the filterPktData, the
 packet will fail this data match.
 (2) For each relevant bit from the packet with the
 corresponding filterPktDataNotMask bit set to
 zero, if the bit from the packet is not equal to
 the corresponding bit from the filterPktData,
 then the packet will fail this data match.
 (3) If for every relevant bit from the packet with the
 corresponding filterPktDataNotMask bit set to one,
 the bit from the packet is equal to the
 corresponding bit from the filterPktData, then
 the packet will fail this data match.
 Any packets that have not failed any of the three
 matches above have passed this data match. In
 particular, a zero length filter will match any
 packet.
 This object may not be modified if the associated
 filterStatus object is equal to valid(1)."
 ::= { filterEntry 4 }
 filterPktDataMask OBJECT-TYPE
 SYNTAX OCTET STRING
 ACCESS read-write
 STATUS mandatory
Waldbusser [Page 64]

RFC 1757 Remote Network Monitoring MIB February 1995
 DESCRIPTION
 "The mask that is applied to the match process.
 After adjusting this mask for the offset, only those
 bits in the received packet that correspond to bits
 set in this mask are relevant for further processing
 by the match algorithm. The offset is applied to
 filterPktDataMask in the same way it is applied to the
 filter. For the purposes of the matching algorithm,
 if the associated filterPktData object is longer
 than this mask, this mask is conceptually extended
 with '1' bits until it reaches the length of the
 filterPktData object.
 This object may not be modified if the associated
 filterStatus object is equal to valid(1)."
 ::= { filterEntry 5 }
 filterPktDataNotMask OBJECT-TYPE
 SYNTAX OCTET STRING
 ACCESS read-write
 STATUS mandatory
 DESCRIPTION
 "The inversion mask that is applied to the match
 process. After adjusting this mask for the offset,
 those relevant bits in the received packet that
 correspond to bits cleared in this mask must all be
 equal to their corresponding bits in the
 filterPktData object for the packet to be accepted.
 In addition, at least one of those relevant bits in
 the received packet that correspond to bits set in
 this mask must be different to its corresponding bit
 in the filterPktData object.
 For the purposes of the matching algorithm, if the
 associated filterPktData object is longer than this
 mask, this mask is conceptually extended with '0'
 bits until it reaches the length of the
 filterPktData object.
 This object may not be modified if the associated
 filterStatus object is equal to valid(1)."
 ::= { filterEntry 6 }
 filterPktStatus OBJECT-TYPE
 SYNTAX INTEGER
 ACCESS read-write
 STATUS mandatory
 DESCRIPTION
Waldbusser [Page 65]

RFC 1757 Remote Network Monitoring MIB February 1995
 "The status that is to be matched with the input
 packet. The only bits relevant to this match
 algorithm are those that have the corresponding
 filterPktStatusMask bit equal to one. The following
 two rules are then applied to every packet:
 (1) For each relevant bit from the packet status
 with the corresponding filterPktStatusNotMask bit
 set to zero, if the bit from the packet status is
 not equal to the corresponding bit from the
 filterPktStatus, then the packet will fail this
 status match.
 (2) If for every relevant bit from the packet status
 with the corresponding filterPktStatusNotMask bit
 set to one, the bit from the packet status is
 equal to the corresponding bit from the
 filterPktStatus, then the packet will fail this
 status match.
 Any packets that have not failed either of the two
 matches above have passed this status match. In
 particular, a zero length status filter will match any
 packet's status.
 The value of the packet status is a sum. This sum
 initially takes the value zero. Then, for each
 error, E, that has been discovered in this packet,
 2 raised to a value representing E is added to the
 sum. The errors and the bits that represent them are
 dependent on the media type of the interface that
 this channel is receiving packets from.
 The errors defined for a packet captured off of an
 Ethernet interface are as follows:
 bit # Error
 0 Packet is longer than 1518 octets
 1 Packet is shorter than 64 octets
 2 Packet experienced a CRC or Alignment
 error
 For example, an Ethernet fragment would have a
 value of 6 (2^1 + 2^2).
 As this MIB is expanded to new media types, this
 object will have other media-specific errors
 defined.
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RFC 1757 Remote Network Monitoring MIB February 1995
 For the purposes of this status matching algorithm,
 if the packet status is longer than this
 filterPktStatus object, this object is conceptually
 extended with '0' bits until it reaches the size of
 the packet status.
 This object may not be modified if the associated
 filterStatus object is equal to valid(1)."
 ::= { filterEntry 7 }
 filterPktStatusMask OBJECT-TYPE
 SYNTAX INTEGER
 ACCESS read-write
 STATUS mandatory
 DESCRIPTION
 "The mask that is applied to the status match
 process. Only those bits in the received packet
 that correspond to bits set in this mask are
 relevant for further processing by the status match
 algorithm. For the purposes of the matching
 algorithm, if the associated filterPktStatus object
 is longer than this mask, this mask is conceptually
 extended with '1' bits until it reaches the size of
 the filterPktStatus. In addition, if a packet
 status is longer than this mask, this mask is
 conceptually extended with '0' bits until it reaches
 the size of the packet status.
 This object may not be modified if the associated
 filterStatus object is equal to valid(1)."
 ::= { filterEntry 8 }
 filterPktStatusNotMask OBJECT-TYPE
 SYNTAX INTEGER
 ACCESS read-write
 STATUS mandatory
 DESCRIPTION
 "The inversion mask that is applied to the status
 match process. Those relevant bits in the received
 packet status that correspond to bits cleared in
 this mask must all be equal to their corresponding
 bits in the filterPktStatus object for the packet to
 be accepted. In addition, at least one of those
 relevant bits in the received packet status that
 correspond to bits set in this mask must be
 different to its corresponding bit in the
 filterPktStatus object for the packet to be
 accepted.
Waldbusser [Page 67]

RFC 1757 Remote Network Monitoring MIB February 1995
 For the purposes of the matching algorithm, if the
 associated filterPktStatus object or a packet status
 is longer than this mask, this mask is conceptually
 extended with '0' bits until it reaches the longer
 of the lengths of the filterPktStatus object and the
 packet status.
 This object may not be modified if the associated
 filterStatus object is equal to valid(1)."
 ::= { filterEntry 9 }
 filterOwner OBJECT-TYPE
 SYNTAX OwnerString
 ACCESS read-write
 STATUS mandatory
 DESCRIPTION
 "The entity that configured this entry and is
 therefore using the resources assigned to it."
 ::= { filterEntry 10 }
 filterStatus OBJECT-TYPE
 SYNTAX EntryStatus
 ACCESS read-write
 STATUS mandatory
 DESCRIPTION
 "The status of this filter entry."
 ::= { filterEntry 11 }
 channelTable OBJECT-TYPE
 SYNTAX SEQUENCE OF ChannelEntry
 ACCESS not-accessible
 STATUS mandatory
 DESCRIPTION
 "A list of packet channel entries."
 ::= { filter 2 }
 channelEntry OBJECT-TYPE
 SYNTAX ChannelEntry
 ACCESS not-accessible
 STATUS mandatory
 DESCRIPTION
 "A set of parameters for a packet channel applied on a
 particular interface. As an example, an instance of
 the channelMatches object might be named
 channelMatches.3"
 INDEX { channelIndex }
 ::= { channelTable 1 }
Waldbusser [Page 68]

RFC 1757 Remote Network Monitoring MIB February 1995
 ChannelEntry ::= SEQUENCE {
 channelIndex INTEGER (1..65535),
 channelIfIndex INTEGER (1..65535),
 channelAcceptType INTEGER,
 channelDataControl INTEGER,
 channelTurnOnEventIndex INTEGER (0..65535),
 channelTurnOffEventIndex INTEGER (0..65535),
 channelEventIndex INTEGER (0..65535),
 channelEventStatus INTEGER,
 channelMatches Counter,
 channelDescription DisplayString (SIZE (0..127)),
 channelOwner OwnerString,
 channelStatus EntryStatus
 }
 channelIndex OBJECT-TYPE
 SYNTAX INTEGER (1..65535)
 ACCESS read-only
 STATUS mandatory
 DESCRIPTION
 "An index that uniquely identifies an entry in the
 channel table. Each such entry defines one channel,
 a logical data and event stream.
 It is suggested that before creating a channel, an
 application should scan all instances of the
 filterChannelIndex object to make sure that there
 are no pre-existing filters that would be
 inadvertently be linked to the channel."
 ::= { channelEntry 1 }
 channelIfIndex OBJECT-TYPE
 SYNTAX INTEGER (1..65535)
 ACCESS read-write
 STATUS mandatory
 DESCRIPTION
 "The value of this object uniquely identifies the
 interface on this remote network monitoring device
 to which the associated filters are applied to allow
 data into this channel. The interface identified by
 a particular value of this object is the same
 interface as identified by the same value of the
 ifIndex object, defined in RFC 1213 and RFC 1573
 [4,6].
 The filters in this group are applied to all packets
 on the local network segment attached to the
 identified interface.
Waldbusser [Page 69]

RFC 1757 Remote Network Monitoring MIB February 1995
 An agent may or may not be able to tell if
 fundamental changes to the media of the interface
 have occurred and necessitate an invalidation of
 this entry. For example, a hot-pluggable ethernet
 card could be pulled out and replaced by a
 token-ring card. In such a case, if the agent has
 such knowledge of the change, it is recommended that
 it invalidate this entry.
 This object may not be modified if the associated
 channelStatus object is equal to valid(1)."
 ::= { channelEntry 2 }
 channelAcceptType OBJECT-TYPE
 SYNTAX INTEGER {
 acceptMatched(1),
 acceptFailed(2)
 }
 ACCESS read-write
 STATUS mandatory
 DESCRIPTION
 "This object controls the action of the filters
 associated with this channel. If this object is equal
 to acceptMatched(1), packets will be accepted to this
 channel if they are accepted by both the packet data
 and packet status matches of an associated filter. If
 this object is equal to acceptFailed(2), packets will
 be accepted to this channel only if they fail either
 the packet data match or the packet status match of
 each of the associated filters.
 In particular, a channel with no associated filters
 will match no packets if set to acceptMatched(1)
 case and will match all packets in the
 acceptFailed(2) case.
 This object may not be modified if the associated
 channelStatus object is equal to valid(1)."
 ::= { channelEntry 3 }
 channelDataControl OBJECT-TYPE
 SYNTAX INTEGER {
 on(1),
 off(2)
 }
 ACCESS read-write
 STATUS mandatory
 DESCRIPTION
Waldbusser [Page 70]

RFC 1757 Remote Network Monitoring MIB February 1995
 "This object controls the flow of data through this
 channel. If this object is on(1), data, status and
 events flow through this channel. If this object is
 off(2), data, status and events will not flow
 through this channel."
 DEFVAL { off }
 ::= { channelEntry 4 }
 channelTurnOnEventIndex OBJECT-TYPE
 SYNTAX INTEGER (0..65535)
 ACCESS read-write
 STATUS mandatory
 DESCRIPTION
 "The value of this object identifies the event
 that is configured to turn the associated
 channelDataControl from off to on when the event is
 generated. The event identified by a particular value
 of this object is the same event as identified by the
 same value of the eventIndex object. If there is no
 corresponding entry in the eventTable, then no
 association exists. In fact, if no event is intended
 for this channel, channelTurnOnEventIndex must be
 set to zero, a non-existent event index.
 This object may not be modified if the associated
 channelStatus object is equal to valid(1)."
 ::= { channelEntry 5 }
 channelTurnOffEventIndex OBJECT-TYPE
 SYNTAX INTEGER (0..65535)
 ACCESS read-write
 STATUS mandatory
 DESCRIPTION
 "The value of this object identifies the event
 that is configured to turn the associated
 channelDataControl from on to off when the event is
 generated. The event identified by a particular value
 of this object is the same event as identified by the
 same value of the eventIndex object. If there is no
 corresponding entry in the eventTable, then no
 association exists. In fact, if no event is intended
 for this channel, channelTurnOffEventIndex must be
 set to zero, a non-existent event index.
 This object may not be modified if the associated
 channelStatus object is equal to valid(1)."
 ::= { channelEntry 6 }
Waldbusser [Page 71]

RFC 1757 Remote Network Monitoring MIB February 1995
 channelEventIndex OBJECT-TYPE
 SYNTAX INTEGER (0..65535)
 ACCESS read-write
 STATUS mandatory
 DESCRIPTION
 "The value of this object identifies the event
 that is configured to be generated when the
 associated channelDataControl is on and a packet
 is matched. The event identified by a particular
 value of this object is the same event as identified
 by the same value of the eventIndex object. If
 there is no corresponding entry in the eventTable,
 then no association exists. In fact, if no event is
 intended for this channel, channelEventIndex must be
 set to zero, a non-existent event index.
 This object may not be modified if the associated
 channelStatus object is equal to valid(1)."
 ::= { channelEntry 7 }
 channelEventStatus OBJECT-TYPE
 SYNTAX INTEGER {
 eventReady(1),
 eventFired(2),
 eventAlwaysReady(3)
 }
 ACCESS read-write
 STATUS mandatory
 DESCRIPTION
 "The event status of this channel.
 If this channel is configured to generate events
 when packets are matched, a means of controlling
 the flow of those events is often needed. When
 this object is equal to eventReady(1), a single
 event may be generated, after which this object
 will be set by the probe to eventFired(2). While
 in the eventFired(2) state, no events will be
 generated until the object is modified to
 eventReady(1) (or eventAlwaysReady(3)). The
 management station can thus easily respond to a
 notification of an event by re-enabling this object.
 If the management station wishes to disable this
 flow control and allow events to be generated
 at will, this object may be set to
 eventAlwaysReady(3). Disabling the flow control
 is discouraged as it can result in high network
Waldbusser [Page 72]

RFC 1757 Remote Network Monitoring MIB February 1995
 traffic or other performance problems."
 DEFVAL { eventReady }
 ::= { channelEntry 8 }
 channelMatches OBJECT-TYPE
 SYNTAX Counter
 ACCESS read-only
 STATUS mandatory
 DESCRIPTION
 "The number of times this channel has matched a
 packet. Note that this object is updated even when
 channelDataControl is set to off."
 ::= { channelEntry 9 }
 channelDescription OBJECT-TYPE
 SYNTAX DisplayString (SIZE (0..127))
 ACCESS read-write
 STATUS mandatory
 DESCRIPTION
 "A comment describing this channel."
 ::= { channelEntry 10 }
 channelOwner OBJECT-TYPE
 SYNTAX OwnerString
 ACCESS read-write
 STATUS mandatory
 DESCRIPTION
 "The entity that configured this entry and is
 therefore using the resources assigned to it."
 ::= { channelEntry 11 }
 channelStatus OBJECT-TYPE
 SYNTAX EntryStatus
 ACCESS read-write
 STATUS mandatory
 DESCRIPTION
 "The status of this channel entry."
 ::= { channelEntry 12 }
 -- The Packet Capture Group
 -- Implementation of the Packet Capture group is optional.
 --
 -- The Packet Capture Group requires implementation of the
 -- Filter Group.
 --
 -- The Packet Capture group allows packets to be captured
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 -- upon a filter match. The bufferControlTable controls
 -- the captured packets output from a channel that is
 -- associated with it. The captured packets are placed
 -- in entries in the captureBufferTable. These entries are
 -- associated with the bufferControlEntry on whose behalf they
 -- were stored.
 bufferControlTable OBJECT-TYPE
 SYNTAX SEQUENCE OF BufferControlEntry
 ACCESS not-accessible
 STATUS mandatory
 DESCRIPTION
 "A list of buffers control entries."
 ::= { capture 1 }
 bufferControlEntry OBJECT-TYPE
 SYNTAX BufferControlEntry
 ACCESS not-accessible
 STATUS mandatory
 DESCRIPTION
 "A set of parameters that control the collection of
 a stream of packets that have matched filters. As
 an example, an instance of the
 bufferControlCaptureSliceSize object might be named
 bufferControlCaptureSliceSize.3"
 INDEX { bufferControlIndex }
 ::= { bufferControlTable 1 }
 BufferControlEntry ::= SEQUENCE {
 bufferControlIndex INTEGER (1..65535),
 bufferControlChannelIndex INTEGER (1..65535),
 bufferControlFullStatus INTEGER,
 bufferControlFullAction INTEGER,
 bufferControlCaptureSliceSize INTEGER,
 bufferControlDownloadSliceSize INTEGER,
 bufferControlDownloadOffset INTEGER,
 bufferControlMaxOctetsRequested INTEGER,
 bufferControlMaxOctetsGranted INTEGER,
 bufferControlCapturedPackets INTEGER,
 bufferControlTurnOnTime TimeTicks,
 bufferControlOwner OwnerString,
 bufferControlStatus EntryStatus
 }
 bufferControlIndex OBJECT-TYPE
 SYNTAX INTEGER (1..65535)
 ACCESS read-only
 STATUS mandatory
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 DESCRIPTION
 "An index that uniquely identifies an entry
 in the bufferControl table. The value of this
 index shall never be zero. Each such
 entry defines one set of packets that is
 captured and controlled by one or more filters."
 ::= { bufferControlEntry 1 }
 bufferControlChannelIndex OBJECT-TYPE
 SYNTAX INTEGER (1..65535)
 ACCESS read-write
 STATUS mandatory
 DESCRIPTION
 "An index that identifies the channel that is the
 source of packets for this bufferControl table.
 The channel identified by a particular value of this
 index is the same as identified by the same value of
 the channelIndex object.
 This object may not be modified if the associated
 bufferControlStatus object is equal to valid(1)."
 ::= { bufferControlEntry 2 }
 bufferControlFullStatus OBJECT-TYPE
 SYNTAX INTEGER {
 spaceAvailable(1),
 full(2)
 }
 ACCESS read-only
 STATUS mandatory
 DESCRIPTION
 "This object shows whether the buffer has room to
 accept new packets or if it is full.
 If the status is spaceAvailable(1), the buffer is
 accepting new packets normally. If the status is
 full(2) and the associated bufferControlFullAction
 object is wrapWhenFull, the buffer is accepting new
 packets by deleting enough of the oldest packets
 to make room for new ones as they arrive. Otherwise,
 if the status is full(2) and the
 bufferControlFullAction object is lockWhenFull,
 then the buffer has stopped collecting packets.
 When this object is set to full(2) the probe must
 not later set it to spaceAvailable(1) except in the
 case of a significant gain in resources such as
 an increase of bufferControlOctetsGranted. In
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 particular, the wrap-mode action of deleting old
 packets to make room for newly arrived packets
 must not affect the value of this object."
 ::= { bufferControlEntry 3 }
 bufferControlFullAction OBJECT-TYPE
 SYNTAX INTEGER {
 lockWhenFull(1),
 wrapWhenFull(2) -- FIFO
 }
 ACCESS read-write
 STATUS mandatory
 DESCRIPTION
 "Controls the action of the buffer when it
 reaches the full status. When in the lockWhenFull(1)
 state and a packet is added to the buffer that
 fills the buffer, the bufferControlFullStatus will
 be set to full(2) and this buffer will stop capturing
 packets."
 ::= { bufferControlEntry 4 }
 bufferControlCaptureSliceSize OBJECT-TYPE
 SYNTAX INTEGER
 ACCESS read-write
 STATUS mandatory
 DESCRIPTION
 "The maximum number of octets of each packet
 that will be saved in this capture buffer.
 For example, if a 1500 octet packet is received by
 the probe and this object is set to 500, then only
 500 octets of the packet will be stored in the
 associated capture buffer. If this variable is set
 to 0, the capture buffer will save as many octets
 as is possible.
 This object may not be modified if the associated
 bufferControlStatus object is equal to valid(1)."
 DEFVAL { 100 }
 ::= { bufferControlEntry 5 }
 bufferControlDownloadSliceSize OBJECT-TYPE
 SYNTAX INTEGER
 ACCESS read-write
 STATUS mandatory
 DESCRIPTION
 "The maximum number of octets of each packet
 in this capture buffer that will be returned in
 an SNMP retrieval of that packet. For example,
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 if 500 octets of a packet have been stored in the
 associated capture buffer, the associated
 bufferControlDownloadOffset is 0, and this
 object is set to 100, then the captureBufferPacket
 object that contains the packet will contain only
 the first 100 octets of the packet.
 A prudent manager will take into account possible
 interoperability or fragmentation problems that may
 occur if the download slice size is set too large.
 In particular, conformant SNMP implementations are not
 required to accept messages whose length exceeds 484
 octets, although they are encouraged to support larger
 datagrams whenever feasible."
 DEFVAL { 100 }
 ::= { bufferControlEntry 6 }
 bufferControlDownloadOffset OBJECT-TYPE
 SYNTAX INTEGER
 ACCESS read-write
 STATUS mandatory
 DESCRIPTION
 "The offset of the first octet of each packet
 in this capture buffer that will be returned in
 an SNMP retrieval of that packet. For example,
 if 500 octets of a packet have been stored in the
 associated capture buffer and this object is set to
 100, then the captureBufferPacket object that
 contains the packet will contain bytes starting
 100 octets into the packet."
 DEFVAL { 0 }
 ::= { bufferControlEntry 7 }
 bufferControlMaxOctetsRequested OBJECT-TYPE
 SYNTAX INTEGER
 ACCESS read-write
 STATUS mandatory
 DESCRIPTION
 "The requested maximum number of octets to be
 saved in this captureBuffer, including any
 implementation-specific overhead. If this variable
 is set to -1, the capture buffer will save as many
 octets as is possible.
 When this object is created or modified, the probe
 should set bufferControlMaxOctetsGranted as closely
 to this object as is possible for the particular probe
 implementation and available resources. However, if
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RFC 1757 Remote Network Monitoring MIB February 1995
 the object has the special value of -1, the probe
 must set bufferControlMaxOctetsGranted to -1."
 DEFVAL { -1 }
 ::= { bufferControlEntry 8 }
 bufferControlMaxOctetsGranted OBJECT-TYPE
 SYNTAX INTEGER
 ACCESS read-only
 STATUS mandatory
 DESCRIPTION
 "The maximum number of octets that can be
 saved in this captureBuffer, including overhead.
 If this variable is -1, the capture buffer will save
 as many octets as possible.
 When the bufferControlMaxOctetsRequested object is
 created or modified, the probe should set this object
 as closely to the requested value as is possible for
 the particular probe implementation and available
 resources.
 However, if the request object has the special value
 of -1, the probe must set this object to -1.
 The probe must not lower this value except as a result
 of a modification to the associated
 bufferControlMaxOctetsRequested object.
 When this maximum number of octets is reached
 and a new packet is to be added to this
 capture buffer and the corresponding
 bufferControlFullAction is set to wrapWhenFull(2),
 enough of the oldest packets associated with this
 capture buffer shall be deleted by the agent so
 that the new packet can be added. If the
 corresponding bufferControlFullAction is set to
 lockWhenFull(1), the new packet shall be discarded.
 In either case, the probe must set
 bufferControlFullStatus to full(2).
 When the value of this object changes to a value less
 than the current value, entries are deleted from
 the captureBufferTable associated with this
 bufferControlEntry. Enough of the
 oldest of these captureBufferEntries shall be
 deleted by the agent so that the number of octets
 used remains less than or equal to the new value of
 this object.
 When the value of this object changes to a value
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RFC 1757 Remote Network Monitoring MIB February 1995
 greater than the current value, the number of
 associated captureBufferEntries may be allowed to
 grow."
 ::= { bufferControlEntry 9 }
 bufferControlCapturedPackets OBJECT-TYPE
 SYNTAX INTEGER
 ACCESS read-only
 STATUS mandatory
 DESCRIPTION
 "The number of packets currently in this
 captureBuffer."
 ::= { bufferControlEntry 10 }
 bufferControlTurnOnTime OBJECT-TYPE
 SYNTAX TimeTicks
 ACCESS read-only
 STATUS mandatory
 DESCRIPTION
 "The value of sysUpTime when this capture buffer was
 first turned on."
 ::= { bufferControlEntry 11 }
 bufferControlOwner OBJECT-TYPE
 SYNTAX OwnerString
 ACCESS read-write
 STATUS mandatory
 DESCRIPTION
 "The entity that configured this entry and is
 therefore using the resources assigned to it."
 ::= { bufferControlEntry 12 }
 bufferControlStatus OBJECT-TYPE
 SYNTAX EntryStatus
 ACCESS read-write
 STATUS mandatory
 DESCRIPTION
 "The status of this buffer Control Entry."
 ::= { bufferControlEntry 13 }
 captureBufferTable OBJECT-TYPE
 SYNTAX SEQUENCE OF CaptureBufferEntry
 ACCESS not-accessible
 STATUS mandatory
 DESCRIPTION
 "A list of packets captured off of a channel."
 ::= { capture 2 }
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RFC 1757 Remote Network Monitoring MIB February 1995
 captureBufferEntry OBJECT-TYPE
 SYNTAX CaptureBufferEntry
 ACCESS not-accessible
 STATUS mandatory
 DESCRIPTION
 "A packet captured off of an attached network. As an
 example, an instance of the captureBufferPacketData
 object might be named captureBufferPacketData.3.1783"
 INDEX { captureBufferControlIndex, captureBufferIndex }
 ::= { captureBufferTable 1 }
 CaptureBufferEntry ::= SEQUENCE {
 captureBufferControlIndex INTEGER (1..65535),
 captureBufferIndex INTEGER (1..2147483647),
 captureBufferPacketID INTEGER,
 captureBufferPacketData OCTET STRING,
 captureBufferPacketLength INTEGER,
 captureBufferPacketTime INTEGER,
 captureBufferPacketStatus INTEGER
 }
 captureBufferControlIndex OBJECT-TYPE
 SYNTAX INTEGER (1..65535)
 ACCESS read-only
 STATUS mandatory
 DESCRIPTION
 "The index of the bufferControlEntry with which
 this packet is associated."
 ::= { captureBufferEntry 1 }
 captureBufferIndex OBJECT-TYPE
 SYNTAX INTEGER (1..2147483647)
 ACCESS read-only
 STATUS mandatory
 DESCRIPTION
 "An index that uniquely identifies an entry
 in the captureBuffer table associated with a
 particular bufferControlEntry. This index will
 start at 1 and increase by one for each new packet
 added with the same captureBufferControlIndex.
 Should this value reach 2147483647, the next packet
 added with the same captureBufferControlIndex shall
 cause this value to wrap around to 1."
 ::= { captureBufferEntry 2 }
 captureBufferPacketID OBJECT-TYPE
 SYNTAX INTEGER
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RFC 1757 Remote Network Monitoring MIB February 1995
 ACCESS read-only
 STATUS mandatory
 DESCRIPTION
 "An index that describes the order of packets
 that are received on a particular interface.
 The packetID of a packet captured on an
 interface is defined to be greater than the
 packetID's of all packets captured previously on
 the same interface. As the captureBufferPacketID
 object has a maximum positive value of 2^31 - 1,
 any captureBufferPacketID object shall have the
 value of the associated packet's packetID mod 2^31."
 ::= { captureBufferEntry 3 }
 captureBufferPacketData OBJECT-TYPE
 SYNTAX OCTET STRING
 ACCESS read-only
 STATUS mandatory
 DESCRIPTION
 "The data inside the packet, starting at the
 beginning of the packet plus any offset specified in
 the associated bufferControlDownloadOffset,
 including any link level headers. The length of the
 data in this object is the minimum of the length of
 the captured packet minus the offset, the length of
 the associated bufferControlCaptureSliceSize minus
 the offset, and the associated
 bufferControlDownloadSliceSize. If this minimum is
 less than zero, this object shall have a length of
 zero."
 ::= { captureBufferEntry 4 }
 captureBufferPacketLength OBJECT-TYPE
 SYNTAX INTEGER
 ACCESS read-only
 STATUS mandatory
 DESCRIPTION
 "The actual length (off the wire) of the packet stored
 in this entry, including FCS octets."
 ::= { captureBufferEntry 5 }
 captureBufferPacketTime OBJECT-TYPE
 SYNTAX INTEGER
 ACCESS read-only
 STATUS mandatory
 DESCRIPTION
 "The number of milliseconds that had passed since
 this capture buffer was first turned on when this
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RFC 1757 Remote Network Monitoring MIB February 1995
 packet was captured."
 ::= { captureBufferEntry 6 }
 captureBufferPacketStatus OBJECT-TYPE
 SYNTAX INTEGER
 ACCESS read-only
 STATUS mandatory
 DESCRIPTION
 "A value which indicates the error status of this
 packet.
 The value of this object is defined in the same way as
 filterPktStatus. The value is a sum. This sum
 initially takes the value zero. Then, for each
 error, E, that has been discovered in this packet,
 2 raised to a value representing E is added to the
 sum.
 The errors defined for a packet captured off of an
 Ethernet interface are as follows:
 bit # Error
 0 Packet is longer than 1518 octets
 1 Packet is shorter than 64 octets
 2 Packet experienced a CRC or Alignment
 error
 3 First packet in this capture buffer after
 it was detected that some packets were
 not processed correctly.
 4 Packet's order in buffer is only
 approximate (May only be set for packets
 sent from the probe)
 For example, an Ethernet fragment would have a
 value of 6 (2^1 + 2^2).
 As this MIB is expanded to new media types, this
 object will have other media-specific errors defined."
 ::= { captureBufferEntry 7 }
 -- The Event Group
 -- Implementation of the Event group is optional.
 --
 -- The Event group controls the generation and notification
 -- of events from this device. Each entry in the eventTable
 -- describes the parameters of the event that can be
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RFC 1757 Remote Network Monitoring MIB February 1995
 -- triggered. Each event entry is fired by an associated
 -- condition located elsewhere in the MIB. An event entry
 -- may also be associated- with a function elsewhere in the
 -- MIB that will be executed when the event is generated. For
 -- example, a channel may be turned on or off by the firing
 -- of an event.
 --
 -- Each eventEntry may optionally specify that a log entry
 -- be created on its behalf whenever the event occurs.
 -- Each entry may also specify that notification should
 -- occur by way of SNMP trap messages. In this case, the
 -- community for the trap message is given in the associated
 -- eventCommunity object. The enterprise and specific trap
 -- fields of the trap are determined by the condition that
 -- triggered the event. Two traps are defined: risingAlarm
 -- and fallingAlarm. If the eventTable is triggered by a
 -- condition specified elsewhere, the enterprise and
 -- specific trap fields must be specified for traps
 -- generated for that condition.
 eventTable OBJECT-TYPE
 SYNTAX SEQUENCE OF EventEntry
 ACCESS not-accessible
 STATUS mandatory
 DESCRIPTION
 "A list of events to be generated."
 ::= { event 1 }
 eventEntry OBJECT-TYPE
 SYNTAX EventEntry
 ACCESS not-accessible
 STATUS mandatory
 DESCRIPTION
 "A set of parameters that describe an event to be
 generated when certain conditions are met. As an
 example, an instance of the eventLastTimeSent object
 might be named eventLastTimeSent.6"
 INDEX { eventIndex }
 ::= { eventTable 1 }
 EventEntry ::= SEQUENCE {
 eventIndex INTEGER (1..65535),
 eventDescription DisplayString (SIZE (0..127)),
 eventType INTEGER,
 eventCommunity OCTET STRING (SIZE (0..127)),
 eventLastTimeSent TimeTicks,
 eventOwner OwnerString,
 eventStatus EntryStatus
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RFC 1757 Remote Network Monitoring MIB February 1995
 }
 eventIndex OBJECT-TYPE
 SYNTAX INTEGER (1..65535)
 ACCESS read-only
 STATUS mandatory
 DESCRIPTION
 "An index that uniquely identifies an entry in the
 event table. Each such entry defines one event that
 is to be generated when the appropriate conditions
 occur."
 ::= { eventEntry 1 }
 eventDescription OBJECT-TYPE
 SYNTAX DisplayString (SIZE (0..127))
 ACCESS read-write
 STATUS mandatory
 DESCRIPTION
 "A comment describing this event entry."
 ::= { eventEntry 2 }
 eventType OBJECT-TYPE
 SYNTAX INTEGER {
 none(1),
 log(2),
 snmp-trap(3), -- send an SNMP trap
 log-and-trap(4)
 }
 ACCESS read-write
 STATUS mandatory
 DESCRIPTION
 "The type of notification that the probe will make
 about this event. In the case of log, an entry is
 made in the log table for each event. In the case of
 snmp-trap, an SNMP trap is sent to one or more
 management stations."
 ::= { eventEntry 3 }
 eventCommunity OBJECT-TYPE
 SYNTAX OCTET STRING (SIZE (0..127))
 ACCESS read-write
 STATUS mandatory
 DESCRIPTION
 "If an SNMP trap is to be sent, it will be sent to
 the SNMP community specified by this octet string.
 In the future this table will be extended to include
 the party security mechanism. This object shall be
 set to a string of length zero if it is intended that
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RFC 1757 Remote Network Monitoring MIB February 1995
 that mechanism be used to specify the destination of
 the trap."
 ::= { eventEntry 4 }
 eventLastTimeSent OBJECT-TYPE
 SYNTAX TimeTicks
 ACCESS read-only
 STATUS mandatory
 DESCRIPTION
 "The value of sysUpTime at the time this event
 entry last generated an event. If this entry has
 not generated any events, this value will be
 zero."
 ::= { eventEntry 5 }
 eventOwner OBJECT-TYPE
 SYNTAX OwnerString
 ACCESS read-write
 STATUS mandatory
 DESCRIPTION
 "The entity that configured this entry and is
 therefore using the resources assigned to it.
 If this object contains a string starting with
 'monitor' and has associated entries in the log
 table, all connected management stations should
 retrieve those log entries, as they may have
 significance to all management stations connected to
 this device"
 ::= { eventEntry 6 }
 eventStatus OBJECT-TYPE
 SYNTAX EntryStatus
 ACCESS read-write
 STATUS mandatory
 DESCRIPTION
 "The status of this event entry.
 If this object is not equal to valid(1), all
 associated log entries shall be deleted by the
 agent."
 ::= { eventEntry 7 }
 --
 logTable OBJECT-TYPE
 SYNTAX SEQUENCE OF LogEntry
 ACCESS not-accessible
 STATUS mandatory
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RFC 1757 Remote Network Monitoring MIB February 1995
 DESCRIPTION
 "A list of events that have been logged."
 ::= { event 2 }
 logEntry OBJECT-TYPE
 SYNTAX LogEntry
 ACCESS not-accessible
 STATUS mandatory
 DESCRIPTION
 "A set of data describing an event that has been
 logged. For example, an instance of the
 logDescription object might be named
 logDescription.6.47"
 INDEX { logEventIndex, logIndex }
 ::= { logTable 1 }
 LogEntry ::= SEQUENCE {
 logEventIndex INTEGER (1..65535),
 logIndex INTEGER (1..2147483647),
 logTime TimeTicks,
 logDescription DisplayString (SIZE (0..255))
 }
 logEventIndex OBJECT-TYPE
 SYNTAX INTEGER (1..65535)
 ACCESS read-only
 STATUS mandatory
 DESCRIPTION
 "The event entry that generated this log
 entry. The log identified by a particular
 value of this index is associated with the same
 eventEntry as identified by the same value
 of eventIndex."
 ::= { logEntry 1 }
 logIndex OBJECT-TYPE
 SYNTAX INTEGER (1..2147483647)
 ACCESS read-only
 STATUS mandatory
 DESCRIPTION
 "An index that uniquely identifies an entry
 in the log table amongst those generated by the
 same eventEntries. These indexes are
 assigned beginning with 1 and increase by one
 with each new log entry. The association
 between values of logIndex and logEntries
 is fixed for the lifetime of each logEntry.
 The agent may choose to delete the oldest
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RFC 1757 Remote Network Monitoring MIB February 1995
 instances of logEntry as required because of
 lack of memory. It is an implementation-specific
 matter as to when this deletion may occur."
 ::= { logEntry 2 }
 logTime OBJECT-TYPE
 SYNTAX TimeTicks
 ACCESS read-only
 STATUS mandatory
 DESCRIPTION
 "The value of sysUpTime when this log entry was
 created."
 ::= { logEntry 3 }
 logDescription OBJECT-TYPE
 SYNTAX DisplayString (SIZE (0..255))
 ACCESS read-only
 STATUS mandatory
 DESCRIPTION
 "An implementation dependent description of the
 event that activated this log entry."
 ::= { logEntry 4 }
 -- These definitions use the TRAP-TYPE macro as
 -- defined in RFC 1215 [10]
 -- Remote Network Monitoring Traps
 risingAlarm TRAP-TYPE
 ENTERPRISE rmon
 VARIABLES { alarmIndex, alarmVariable, alarmSampleType,
 alarmValue, alarmRisingThreshold }
 DESCRIPTION
 "The SNMP trap that is generated when an alarm
 entry crosses its rising threshold and generates
 an event that is configured for sending SNMP
 traps."
 ::= 1
 fallingAlarm TRAP-TYPE
 ENTERPRISE rmon
 VARIABLES { alarmIndex, alarmVariable, alarmSampleType,
 alarmValue, alarmFallingThreshold }
 DESCRIPTION
 "The SNMP trap that is generated when an alarm
 entry crosses its falling threshold and generates
 an event that is configured for sending SNMP
 traps."
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RFC 1757 Remote Network Monitoring MIB February 1995
 ::= 2
 END
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RFC 1757 Remote Network Monitoring MIB February 1995
6. Acknowledgments
 This document was produced by the IETF Remote Network Monitoring
 Working Group.
7. References
 [1] Cerf, V., "IAB Recommendations for the Development of Internet
 Network Management Standards", RFC 1052, NRI, April 1988.
 [2] Cerf, V., "Report of the Second Ad Hoc Network Management Review
 Group", RFC 1109, NRI, August 1989.
 [3] Rose M., and K. McCloghrie, "Structure and Identification of
 Management Information for TCP/IP-based internets", STD 16, RFC
 1155, Performance Systems International, Hughes LAN Systems, May
 1990.
 [4] McCloghrie K., and M. Rose, Editors, "Management Information Base
 for Network Management of TCP/IP-based internets", STD 17, RFC
 1213, Performance Systems International, March 1991.
 [5] Case, J., Fedor, M., Schoffstall, M., and J. Davin, "Simple
 Network Management Protocol", STD 15, RFC 1157, SNMP Research,
 Performance Systems International, Performance Systems
 International, MIT Laboratory for Computer Science, May 1990.
 [6] McCloghrie, K., and F. Kastenholz, "Evolution of the Interfaces
 Group of MIB-II", RFC 1573, Hughes LAN Systems, FTP Software,
 January 1994.
 [7] Information processing systems - Open Systems Interconnection -
 Specification of Abstract Syntax Notation One (ASN.1),
 International Organization for Standardization. International
 Standard 8824, (December, 1987).
 [8] Information processing systems - Open Systems Interconnection -
 Specification of Basic Encoding Rules for Abstract Notation One
 (ASN.1), International Organization for Standardization.
 International Standard 8825, (December, 1987).
 [9] Rose, M., and K. McCloghrie, Editors, "Concise MIB Definitions",
 RFC 1212, Performance Systems International, Hughes LAN Systems,
 March 1991.
 [10] Rose, M., Editor, "A Convention for Defining Traps for use with
 the SNMP", RFC 1215, Performance Systems International, March
 1991.
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RFC 1757 Remote Network Monitoring MIB February 1995
8. Security Considerations
 Security issues are not discussed in this memo.
9. Author's Address
 Steven Waldbusser
 Carnegie Mellon University
 5000 Forbes Ave.
 Pittsburgh, PA 15213
 EMail: waldbusser@cmu.edu
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RFC 1757 Remote Network Monitoring MIB February 1995
10. Appendix: Changes from RFC 1271 
 The RMON MIB has not been significantly changed since RFC 1271 was
 issued.
 Two changes were made to object definitions:
 1) A new status bit has been defined for the
 captureBufferPacketStatus object, indicating that the packet
 order within the capture buffer may not be identical to the
 packet order as received off the wire. This bit may only be used
 for packets transmitted by the probe. Older NMS applications can
 safely ignore this status bit, which might be used by newer
 agents.
 2) The packetMatch trap has been removed. This trap was never
 actually 'approved' and was not added to this document along with
 the risingAlarm and fallingAlarm traps. The packetMatch trap
 could not be throttled, which could cause disruption of normal
 network traffic under some circumstances. An NMS should configure
 a risingAlarm threshold on the appropriate channelMatches
 instance if a trap is desired for a packetMatch event. Note that
 logging of packetMatch events is still supported--only trap
 generation for such events has been removed.
 In addition, several clarifications to individual object definitions
 have been added to assist agent and NMS implementors:
 - global definition of "good packets" and "bad packets"
 - more detailed text governing conceptual row creation and
 modification
 - instructions for probes relating to interface changes and
 disruptions
 - clarification of some ethernet counter definitions
 - recommended formula for calculating network utilization
 - clarification of channel and captureBuffer behavior for some
 unusual conditions
 - examples of proper instance naming for each table
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