This is the new *CloudFormation Template Reference Guide*. Please update your bookmarks and links. For help getting started with CloudFormation, see the [AWS CloudFormation User Guide](https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/Welcome.html).
# AWS::EC2::RouteServerPeer BgpOptions

The BGP configuration options for this peer, including ASN (Autonomous System Number) and BFD (Bidrectional Forwarding Detection) settings.
## Syntax

To declare this entity in your CloudFormation template, use the following syntax:
### JSON

```
{
 "[PeerAsn](#cfn-ec2-routeserverpeer-bgpoptions-peerasn)" : {{Integer}},
 "[PeerLivenessDetection](#cfn-ec2-routeserverpeer-bgpoptions-peerlivenessdetection)" : {{String}}
}
```
### YAML

```
 [PeerAsn](#cfn-ec2-routeserverpeer-bgpoptions-peerasn): {{Integer}}
 [PeerLivenessDetection](#cfn-ec2-routeserverpeer-bgpoptions-peerlivenessdetection): {{String}}
```
## Properties

`PeerAsn` 
The Border Gateway Protocol (BGP) Autonomous System Number (ASN) for the appliance. Valid values are from 1 to 4294967295. We recommend using a private ASN in the 64512–65534 (16-bit ASN) or 4200000000–4294967294 (32-bit ASN) range. 
*Required*: No 
*Type*: Integer 
*Minimum*: `1` 
*Maximum*: `4294967294` 
*Update requires*: [Replacement](https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/using-cfn-updating-stacks-update-behaviors.html#update-replacement)
`PeerLivenessDetection` 
The liveness detection protocol used for the BGP peer. 
The requested liveness detection protocol for the BGP peer. 
+ `bgp-keepalive`: The standard BGP keep alive mechanism ([RFC4271](https://www.rfc-editor.org/rfc/rfc4271#page-21)) that is stable but may take longer to fail-over in cases of network impact or router failure.
+ `bfd`: An additional Bidirectional Forwarding Detection (BFD) protocol ([RFC5880](https://www.rfc-editor.org/rfc/rfc5880)) that enables fast failover by using more sensitive liveness detection.
Defaults to `bgp-keepalive`. 
*Required*: No 
*Type*: String 
*Allowed values*: `bfd | bgp-keepalive` 
*Update requires*: [Replacement](https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/using-cfn-updating-stacks-update-behaviors.html#update-replacement)</div><div class="naked_ctrl">
<form action="/index.cgi/contrast" method="get" name="gate">
<p><a href="http://altstyle.alfasado.net">AltStyle</a> によって変換されたページ <a href="https://docs.aws.amazon.com/AWSCloudFormation/latest/TemplateReference/aws-properties-ec2-routeserverpeer-bgpoptions.md">(-&gt;オリジナル)</a>
/ <label>アドレス: <input type="text" name="naked_post_url" value="https://docs.aws.amazon.com/AWSCloudFormation/latest/TemplateReference/aws-properties-ec2-routeserverpeer-bgpoptions.md" size="22" /></label> <label>モード: <select name="naked_post_mode">
<option value="default">デフォルト</option>
<option value="speech">音声ブラウザ</option>
<option value="ruby">ルビ付き</option>
<option value="contrast" selected="selected">配色反転</option>
<option value="larger-text">文字拡大</option>
<option value="mobile">モバイル</option>
</select>
<input type="submit" value="表示" />
</p>
</form>
</div>