Network Working Group G. Dommety
Request for Comments: 3115 K. Leung
Obsoletes: 3025 cisco Systems
Category: Standards Track April 2001
 Mobile IP Vendor/Organization-Specific Extensions
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.
Copyright Notice
 Copyright (C) The Internet Society (2001). All Rights Reserved.
RFC Editor Note:
 This memo corrects discrepancies between the values assigned for
 CVSE-TYPE-NUMBER and NVSE-TYPE-NUMBER in RFC 3025 and in the Internet
 Assigned Numbers Authority's (IANA) repository. The difference in
 the assigned values are as follows:
 CVSE-TYPE-NUMBER = 37 in RFC 3025
 CVSE-TYPE-NUMBER = 38 in IANA (Under Mobile IP numbers)
 NVSE-TYPE-NUMBER = 133 in RFC 3025
 NVSE-TYPE-NUMBER = 134 in IANA (Under Mobile IP numbers)
 This memo obsoletes RFC 3025, since the current implementations
 follow the IANA assignments.
Abstract
 This document defines two new extensions to Mobile IP. These
 extensions will facilitate equipment vendors and organizations to
 make specific use of these extensions as they see fit for research or
 deployment purposes.
1. Introduction
 Current specification of Mobile IP [1] does not allow for
 organizations and vendors to include organization/vendor-specific
 information in the Mobile IP messages. With the imminent wide scale
 deployment of Mobile IP it is useful to have vendor or organization-
 Specific Extensions to support this capability. This document
 defines two extensions that can be used for making organization
 specific extensions by vendors/organizations for their own specific
 purposes.
1.1. Specification Language
 The keywords "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
 document are to be interpreted as described in RFC 2119 [3].
 In addition, the following words are used to signify the requirements
 of the specification.
 silently discard
 The implementation discards the datagram without further
 processing, and without indicating an error to the sender.
 The implementation SHOULD provide the capability of logging
 the error, including the contents of the discarded datagram,
 and SHOULD record the event in a statistics counter.
2. Vendor/Organization Specific Extensions
 Two Vendor/Organization Specific Extensions are described, Critical
 (CVSE) and Normal (NVSE) Vendor/Organization Specific Extensions.
 The basic differences between the Critical and Normal Extensions are
 that when the Critical extension is encountered but not recognized,
 the message containing the extension MUST be silently discarded,
 whereas when a Normal Vendor/Organization Specific Extension is
 encountered but not recognized, the extension SHOULD be ignored, but
 the rest of the Extensions and message data MUST still be processed.
 Another difference between the two is that Critical
 Vendor/Organization Extension has a length field of two octets and
 the NVSE has a length field of only one octet.
2.1. Critical Vendor/Organization Specific Extension (CVSE)
 The format of this extension is as shown below.
 0 1 2 3
 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 | Type | Reserved | Length |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 | Vendor/Org-ID |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 | Vendor-CVSE-Type | Vendor-CVSE-Value ...
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 Figure 1: Critical Vendor/Organization Specific Extension
 Type CVSE-TYPE-NUMBER 38
 Reserved Reserved for future use. MUST be set to 0 on sending,
 MUST be ignored on reception.
 Length Length in bytes of this extension, not including the Type
 and Length bytes.
 Vendor/Org-ID
 The high-order octet is 0 and the low-order 3 octets are
 the SMI Network Management Private Enterprise Code of the
 Vendor in network byte order, as defined in the Assigned
 Numbers RFC [2].
 Vendor-CVSE-Type
 Indicates the particular type of Vendor-CVSE-Extension.
 The administration of the Vendor-CVSE-Types is done by the
 Vendor.
 Vendor-CVSE-Value
 Vendor/organization specific data of this Vendor-CVSE-
 Extension. These data fields may be published in future
 RFCs. The Vendor-CVSE-Value is zero or more octets. The
 length of this field can be computed from the Length Field
 Value.
 If an implementation does not recognize the CVSE, according to RFC
 2002 [1], the entire packet is to be silently dropped.
2.2. Normal Vendor/Organization Specific Extension (NVSE)
 The format of this extension is as shown below.
 0 1 2 3
 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 | Type | Length | Reserved |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 | Vendor/Org-ID |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 | Vendor-NVSE-Type | Vendor-NVSE-Value ...
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 Figure 2: Normal Vendor/Organization Specific Extension
 Type NVSE-TYPE-NUMBER 134
 Length Length in bytes of this extension, not including the Type
 and Length bytes.
 Reserved Reserved for future use. To be set to 0.
 Vendor/Org-ID
 The high-order octet is 0 and the low-order 3 octets are
 the SMI Network Management Private Enterprise Code of the
 Vendor in network byte order, as defined in the Assigned
 Numbers RFC [2].
 Vendor-NVSE-Type Indicates the particular type of Vendor-NVSE-
 Extension. The administration of the Vendor-NVSE-Types is
 done by the Vendor.
 Vendor-NVSE-Value
 Vendor/organization specific data of this Vendor-NVSE-
 Extension. These data fields may be published in future
 RFCs. The Vendor-NVSE-Value is zero or more octets. The
 length of this field can be computed from the Length
 Field Value.
2.3 Vendor/Organization Specific Extensions Processing Considerations
 When a Mobile IP entity receives a registration request message (or
 any other request/update message) with an extension of type CVSE-
 TYPE-NUMBER and recognizes it, but the extension contains an
 unknown/unsupported vendor ID or Vendor-CVSE-Type, a registration
 reject (or the appropriate deny message) MUST be sent with the error
 code to indicate that the registration was rejected due to the
 presence of an unknown CVSE.
 When a Mobile IP entity receives a registration reply (or any other
 mobile IP reply/acknowledgement message) with an extension of type
 CVSE-TYPE-NUMBER and recognizes it, but the extensions contains an
 unknown/unsupported vendor ID or Vendor-CVSE-Type, the processing is
 performed as described below.
 1. If the Mobile IP entity is a transit node for the reply (i.e.,
 this entity processes and sends the registration reply to another
 entity) a registration reject (or the appropriate deny message) MUST
 be sent with the error code to indicate that the registration was
 rejected due to the presence of an unknown CVSE. For example, FA
 when it receives an unknown CVSE in a registration reply from the HA,
 should send a registration reject to the MN.
 2. If the Mobile IP entity is not a transit node for the reply, the
 reply is treated as a reject (or the appropriate deny message) due to
 the presence of an unknown CVSE.
 While designing enhancements wherein a CVSE is included in a reply
 message, it should noted that the reply message could be discarded by
 the mobile IP entity processing this message. Enhancements that
 include a CVSE should take this into consideration during design.
 When a Mobile IP entity receives a mobile IP related message
 (registration request/reply, advertisement/solicitation, etc.) with
 an extension of type NVSE-TYPE-NUMBER and recognizes it, but the
 extension contains an unknown/unsupported vendor ID or Vendor-NVSE-
 Type, the entire extension is skipped.
 NOTE that according to RFC 2002 [1], when an extension numbered
 within the range 0 through 127 is encountered in a registration
 message but not recognized, the message containing that extension
 MUST be silently discarded. This document is compliant with the
 above specification and specifies the action if the extension of type
 CVSE-TYPE-NUMBER is encountered and recognized, but does not support
 the vendor ID or the vendor type extension within.
2.4 Error Codes
 The following error codes are defined.
 Registration denied by the Foreign agent:
 ERROR-FA-1 100: Unsupported Vendor-ID or
 unable to interpret Vendor-CVSE-Type in the CVSE sent by the
 Mobile Node to the Foreign Agent.
 ERROR-FA-2 101: Unsupported Vendor-ID or
 unable to interpret Vendor-CVSE-Type in the CVSE sent by the
 Home Agent to the Foreign Agent.
 Registration denied by the Home agent:
 ERROR-HA-1 140: Unsupported Vendor-ID or
 unable to interpret Vendor-CVSE-Type in the CVSE sent by the
 Mobile Node to the Home Agent.
 ERROR-HA-2 141: Unsupported Vendor-ID or
 unable to interpret Vendor-CVSE-Type in the CVSE sent by the
 Foreign Agent to the Home Agent.
3. Restrictions
 Multiple TLV's with the types CVSE-TYPE-NUMBER and NVSE-TYPE-NUMBER
 can be included in a message. TLVs with types CVSE-TYPE-NUMBER and
 NVSE-TYPE-NUMBER can be placed anywhere after the fixed portion of
 the Mobile IP message. These TLVs are expected to be protected by
 the corresponding authenticator as necessary. Ordering of these
 TLV's should not be modified by intermediate nodes.
4. IANA Considerations
 The Critical Vendor/Organization Specific Extension (CVSE) as defined
 in Section 2.1 and Normal Vendor/Organization Specific Extension
 (NVSE) as defined in section 2.2 are proposed new extensions to the
 Mobile IP protocol, defined in RFC 2002 [1] and extended in RFC 2356
 [5].
 IANA has assigned a Type value of CVSE-TYPE-NUMBER for the Critical
 Vendor/Organization Specific Extension (CVSE), and a Type value of
 NVSE-TYPE-NUMBER for the Normal Vendor/Organization Specific
 Extension (NVSE). The numbers CVSE-TYPE-NUMBER and NVSE-TYPE-NUMBER
 for the CVSE and the NVSE are taken from the numbering space defined
 for Mobile IP registration extensions [1].
 IANA has assigned new Foreign Agent Error Codes, ERROR-FA-1 and
 ERROR-FA-2 taken from the numbering space defined for Mobile IP
 Foreign Agent error codes [1]. IANA has also assigned new Home Agent
 Error Codes, ERROR-HA-1 and ERROR-HA-2 taken from the numbering space
 defined for Mobile IP Home Agent error codes [1].
5. Security Considerations
 This document assumes that the Mobile IP messages are authenticated
 using a method defined by the Mobile IP protocol. This document does
 not impose any additional requirements on Mobile IP messages from a
 security point of view. So this is not expected to be a security
 issue.
6. Acknowledgments
 The authors would like to thank TR45.4 WG, TR45.6 WG, Basavaraj
 Patil, Phil Roberts, Jouni Malinen, and Patrice Calhoun for their
 useful discussions.
7. References
 [1] Perkins, C., "IP Mobility Support", RFC 2002, October 1996.
 [2] Reynolds, J. and J. Postel, "Assigned Numbers", STD 2, RFC 1700,
 October 1994.
 [3] Bradner, S., "Key words for use in RFCs to Indicate Requirement
 Levels", BCP 14, RFC 2119, March 1997.
 [4] Montenegro, G., "Reverse Tunneling for Mobile IP", RFC 2344, May
 1998.
 [5] Montenegro, G. and V. Gupta, "Sun's SKIP Firewall Traversal for
 Mobile IP", RFC 2356, June 1998.
8. Authors' Addresses
 Gopal Dommety
 Cisco Systems, Inc.
 170 West Tasman Drive
 San Jose, CA 95134
 EMail: gdommety@cisco.com
 Kent Leung
 Cisco Systems, Inc.
 170 West Tasman Drive
 San Jose, CA 95134
 EMail: kleung@cisco.com
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