Description

This article provides some commands (CLI and shell) for troubleshooting BFD issues.

Symptoms

The below commands are useful when troubleshooting BFD issues like flapping/Down/Not coming up scenario. These commands needs to be collected during the issue state and can be used to determine if the BFD packets are being dropped on the device.
 

Solution

Follow below steps for troubleshooting BFD issues

1) Verify connectivity between BFD peers.
2) Use following firewall filter configuration to check if the BFD packets are being sent/received on the interface.
set firewall filter family inet BFD interface-specific
set firewall filter family inet BFD term In from protocol udp
set firewall filter family inet BFD term In from port [4784 3784 3785]
set firewall filter family inet BFD term In from source-address <>
set firewall filter family inet BFD term In from destination-address <>
set firewall filter family inet BFD term In then accept
set firewall filter family inet BFD term In then count BFD-In
set firewall filter family inet BFD term In then log
set firewall filter family inet BFD term Out from protocol udp
set firewall filter family inet BFD term Out from port  [4784 3784 3785]
set firewall filter family inet BFD term Out from destination-address <>
set firewall filter family inet BFD term Out from source-address <>
set firewall filter family inet BFD term Out then accept
set firewall filter family inet BFD term Out then count BFD-OUT
set firewall filter family inet BFD term Out then log
set firewall filter family inet BFD term anything then accept

3) Enable traceoptions for bfd

CLI:
  • show bfd session
  • show ppm transmissions protocol bfd detail
  • show bfd session extensive
  • show pfe statistics traffic
  • show ppm rules

PFE:
  • show ttp statistics
  • show threads
  • show halp-pkt inline-ka session 1
  • show halp-pkt inline-ka session 2
  • show halp-pkt inline-ka tx
  • show halp-pkt inline-ka rx-pt-table
  • show halp-pkt inline-ka all
  • show halp-pkt inline-ka stats
  • show shim jnh bfd-anchor
  • show ukern_traces --------------> get the index id of the all the DFWD handle (DFW-mem, DFW, DFW-error, DFW-API, DFW-detail, EXPR-DFW-Error, EXPR-DFW-API, EXPR-DFW-Detail, debug)
  • Set the ukern_trace handles level as extensive for all the handles
  • show ukern_trace <handle id> (for all the handles in the above step)

Trace the BFD packets where are they getting dropped in PFE. run below commands multiple times for the affected BFD session during the problem state.
  • show ppm statistics protocol bfd
  • show ppm adjacencies protocol bfd
  • show ppm transmits protocol bfd
  • show ppm statistics protocol bfd
  • show ppm inline statistics  
  • show shim jnh statebyte stats dev <PFE of interfaces in question>
  • show filter ------> (get the index# for loopback filter, ppmd filter and hostbound filter)
  • show filter index <index#> counter
  • show toe ka pfe <PFE of interfaces in question>  pe 0 toe-inst 1 stats

Modification History

2024-08-01 : Article Created