The peer capability-advertise command enables optional BGP functions when a BGP peer advertises routes to its peer. The optional BGP functions include route-refresh, general function, 4-byte AS number, and Add-Path.
The undo peer capability-advertise command restores the default setting.
By default, the route-refresh and 4-byte AS number functions are enabled, but the general function and Add-Path are disabled.
peer ipv4-address capability-advertise add-path { both | receive | send }
peer peerIpv6Addr capability-advertise add-path { both | receive | send }
undo peer ipv4-address capability-advertise add-path { both | receive | send }
undo peer peerIpv6Addr capability-advertise add-path { both | receive | send }
| Parameter | Description | Value |
|---|---|---|
| ipv4-address |
Specifies the IPv4 address of a peer. |
The value is in dotted decimal notation. |
| add-path |
Indicates the Add-Path function. add-path takes effect only on IBGP peers. |
- |
| both |
Enables the RR to receive Add-Path routes from and send Add-Path routes to a specified IBGP peer. |
- |
| receive |
Enables the RR to receive Add-Path routes from a specified IBGP peer. |
- |
| send |
Enables the RR to send Add-Path routes to a specified IBGP peer. |
- |
| peerIpv6Addr |
Specifies the IPv6 address of a peer. |
The value is a 32-digit hexadecimal number, in the format of X:X:X:X:X:X:X:X. |
Usage Scenario
There are multiple optional BGP functions when a BGP peer advertises routes to its peer. The optional BGP functions include route-refresh, general function, 4-byte AS number, and Add-Path. You can run the peer capability-advertise command to select one of the functions based on the needs on the live network.
Configuration Impact
If you enable or disable the route-refresh, general function, 4-byte AS number, or Add-Path function, the BGP peer relationship will be re-established, which can lead to a temporary network interruption. Therefore, exercise caution when running the related commands.
Precautions
If a peer is specified when the peer capability-advertise add-path command is run, a peer group is specified when the peer advertise best-external command is run, and then the peer is added to the peer group, the peer cannot inherit the configuration of the peer advertise best-external command from the peer group.