The SRv6  policy with Seamless BFD (S-BFD) was used to provide fast and deterministic failure detection for an explicitly defined SRv6 path. The main objective was to detect data-plane failures that are not visible to the control plane and to trigger immediate traffic protection without waiting for IGP or BGP convergence.

Two SRv6 policies were configured toward the same endpoint: a primary path and a secondary path. Depending on vendor capabilities, S-BFD was either enabled only on the primary path or enabled on both primary and standby paths.

To simulate failure of the active SRv6 path, S-BFD continuity was intentionally disrupted. When only the primary path was monitored with S-BFD, this was achieved by shutting down the S-BFD reflector on the peer device, which caused the head-end to stop receiving S-BFD replies. As a result, the S-BFD session expired and the primary segment list was declared invalid, triggering traffic switchover to the secondary SRv6 policy.

When S-BFD was configured on both primary and standby paths, shutting down the reflector would have impacted both paths simultaneously. Therefore, a traffic filter was applied specifically on the primary path to block S-BFD control packets. This caused loss of continuity only on the active segment list, while the standby path remained operational. Upon S-BFD failure detection on the primary path, traffic was automatically redirected to the standby SRv6 policy.

In both scenarios, S-BFD successfully detected data-plane failure and triggered correct and deterministic switchover behavior.