peer substitute-as
Function
The peer substitute-as command substitutes the AS number of the specified peer in the as-path with the local AS number.
The undo peer substitute-as command cancels the configuration.
By default, the substitution of the AS number is disabled.
Format
peer { group-name | ipv4-address | ipv6-address } substitute-as
undo peer { group-name | ipv4-address | ipv6-address } substitute-as
Parameters
| Parameter | Description | Value |
|---|---|---|
group-name |
Specifies the name of the peer group. It is case-sensitive. |
The name is a string of 1 to 47 characters without any space. It is case-sensitive. |
ipv4-address |
Specifies the IPv4 address of the peer. |
It is in dotted decimal notation. |
ipv6-address |
Specifies the IPv6 address of the peer. |
The address is a 32-digit hexadecimal number in the X:X:X:X:X:X:X:X format. |
ipv4-address is valid only in the BGP-VPN instance IPv4 address family view.
ipv6-address is valid only in the BGP-VPN instance IPv6 address family view.
Usage Guidelines
Usage Scenario
In a scenario where VPN sites in the same site or those that have different private AS numbers communicate through the BGP/MPLS IP VPN backbone network, if a CE and its connected PE in a VPN site establish an EBGP connection, VPN routes from other VPN sites may carry the AS number of this VPN site. As a result, the CE discards the VPN routes, causing a failure in VPN site communication. To prevent this situation from occurring, run the peer substitute-as command on the PE to enable the AS number substitute function.
Prerequisites
The peer as-number command has been used to create a peer or peer group.
Precautions
In case of CE multi-homing, enabling the AS number substitute function may lead to a routing loop within a VPN site. Then you need to configure the peer soo command to prevent the routing loop.