OS10 supports bi-directional forwarding detection (BFD) to detect communication failures on an interface that is a part of a VLT port channel. BFD replaces link-state detection mechanisms in existing routing protocols. It also provides a failure detection solution for links with no routing protocols.
In a VLT domain, BFD provides a high-availability path when communication failures occur in any of the VLT port channel links. The VLT nodes and top-of-rack (ToR) use the VLT port channel links to carry the BFD packets. When any of the VLT port channel links connected to the ToR is down, the BFD packets reach the VLT primary or secondary using the VLTi link. BFD is supported over VLT only when you enable peer routing on both peers.
