peer capability-advertise suppress-4-byte-as

Use peer capability-advertise suppress-4-byte-as to enable 4-byte AS number suppression.

Use undo peer capability-advertise suppress-4-byte-as to disable 4-byte AS number suppression.

Syntax

peer { group-name | ipv6-address [ prefix-length ] } capability-advertise suppress-4-byte-as

undo peer { group-name | ipv6-address [ prefix-length ] } capability-advertise suppress-4-byte-as

Default

The 4-byte AS number suppression feature is disabled.

Views

BGP instance view

BGP-VPN instance view

Predefined user roles

network-admin

Parameters

group-name: Specifies a peer group by its name, a case-sensitive string of 1 to 47 characters. The peer group must have been created.

ipv4-address: Specifies a peer by its IPv4 address. The peer must have been created.

mask-length: Specifies a mask length in the range of 0 to 32. You can use the ipv4-address and mask-length arguments together to specify a subnet. If you specify a subnet, this command enables 4-byte AS number suppression for all dynamic peers in the subnet.

ipv6-address: Specifies a peer by its IPv6 address. The peer must have been created.

prefix-length: Specifies a prefix length in the range of 0 to 128. You can use the ipv6-address and prefix-length arguments together to specify a subnet. If you specify a subnet, this command enables 4-byte AS number suppression for all dynamic peers in the subnet.

Usage guidelines

BGP supports 4-byte AS numbers. The 4-byte AS number occupies four bytes, in the range of 1 to 4294967295. By default, a device sends an Open message to the peer device for session establishment. The Open message indicates that the device supports 4-byte AS numbers. If the peer device supports 2-byte AS numbers instead of 4-byte AS numbers, the session cannot be established. To resolve this issue, enable the 4-byte AS number suppression feature. The device then sends an Open message to inform the peer that it does not support 4-byte AS numbers, so the BGP session can be established.

If the peer device supports 4-byte AS numbers, do not enable the 4-byte AS number suppression feature. If this feature is enabled, the BGP session cannot be established.

Examples

# In BGP instance view, enable 4-byte AS number suppression for peer 1.1.1.1.

<Sysname> system-view
[Sysname] bgp 100
[Sysname-bgp-default] peer 1.1.1.1 as-number 100
[Sysname-bgp-default] peer 1.1.1.1 capability-advertise suppress-4-byte-as

Related commands

display bgp peer