The peer prefix-sid command enables a device to exchange IPv4 prefix SIDs with a specified IPv6 peer.
The undo peer prefix-sid command disables a device from exchanging IPv4 prefix SIDs with a specified IPv6 peer.
This function is disabled by default.
| Parameter | Description | Value |
|---|---|---|
| ipv6-address |
Specifies the IPv6 address of a BGP peer. |
The value is a 32-digit hexadecimal number, in the format of X:X:X:X:X:X:X:X. |
| sid-type5 |
Uses the SRv6-VPN SID TLV (TLV Type 5) to carry SRv6 SID information. By default, the SRv6 Services TLV (TLV Type 4) is used to carry SRv6 SIDs. |
- |
| advertise-srv6-locator |
Uses the SRv6 Services TLV (TLV Type 5) to carry SRv6 SID information, and uses the SRv6 SID Structure sub-sub-TLV to carry locator length information. |
- |
Usage Scenario
In an SRv6 VPN scenario, IPv6 runs on a public network and IPv4 runs on the private network. PEs establish an IPv6 BGP peer relationship to exchange IPv4 private network route information. To enable BGP to exchange IPv4 route information with the specified IPv6 peer in the BGP VPNv4 address family view, run the peer enable command.
To enable a device to exchange IPv4 prefix SIDs with a specified IPv6 peer, run the peer prefix-sid command. In an SRv6 VPN scenario where BFD is used to monitor a locator's reachability, if the primary path fails, BFD goes down, triggering VPN FRR to perform path switching. However, if locator routes are summarized by a P device between PEs, the remote PE can learn only the locator route obtained after routes from the local PE are summarized. Since BFD detection on the remote PE depends on the peer IPv6 address (locator address of the local PE) bound to the BFD session, BFD fails in this case and VPN FRR cannot be triggered to perform path switching. To resolve this problem, specify the advertise-srv6-locator parameter when you run the peer prefix-sid command on the local PE so that the BGP routes that the local PE advertises to the remote PE carry the locator length information. The remote PE uses the SRv6 SID and locator length information carried in the received routes to calculate the local PE's locator. In this way, the peer IPv6 address bound to the BFD session on the remote PE matches the IPv6 address of the local PE's locator, allowing BFD to take effect. In this case, if the primary path fails, VPN FRR is triggered to perform path switching.