SRv6 Unreachable Prefix Announcement

SRv6 Unreachable Prefix Announcement (UPA)enhances fast convergence by signaling the loss of reachability of specific prefixes covered under summarized routes. UPA supports fast traffic rerouting by advertising unreachable prefixes through IGP extensions, causing minimal service disruption.
Our test checked if UPA is generated as intended when there is a node or link failure, ensuring that UPA can trigger backup paths for traffic to flow seamlessly.
For UPA validation the testbed topology consisted of one ingress PE, ABR, and two egress nodes connected to a joint CE router. One egress node that was forwarding the traffic had its loopback address removed, and we monitored the UPA advertisement generated by the ABR. As expected, this advertisement included the affected prefix but had an assigned max metric to indicate it was unreachable to the ingress. Once the UPA update was received, the ingress PE switched to the backup path and continued forwarding traffic.