This document describes how to verify Bidireccional Forwarding Detection (BFD) hardware counters on Distributed Forwarding Card (DFC) linecards for 7600 devices.
Cisco recommends that you have basic knowledge of these topics:
7600 series routers configuration and features
DFC linecard modules configuration
The information in this document is based on 7600 IOS version 15.3.
The information in this document was created from the devices in a specific lab environment. All of the devices used in this document started with a cleared (default) configuration. If your network is live, make sure that you understand the potential impact of any command.
BFD is a network protocol designed to detect subsecond failures in communication in any kind of path between systems (direct physical links, virtual circuits, tunnels, MPLS LSPs, etc).
DFC stands for DFC, the main difference between DFC and CFC linecards is that DFC linecards have an embedded daughter card with an L2 engine and an L3/4 engine, this offloads forwarding lookups that on CFC linecards would be sent to the Supervisor to be done locally on the linecard.
BFD packets are treated in hardware that way they don’t impact the CPU, this means that in DFC cards this packets are always received and forwarded without leaving the linecard.
You can see that R1 does not bring up the BFD Adjacency with his neighbor on Tengig3/21.