Friday, March 20, 2015

Cisco BUG - PIM join does not make it to CPU

Cisco BUG

CSCue52328 Bug Details
PIM joins for some groups not processed at CPU level
Symptom:
Under very rare conditions PIM joins from a downstream switch are not forwarded my mcastfwd to PIM
to be processed. This has been seen under the following conditions

a) Downstream device sending PIM joins is a Arista switch
b) There is a local receiver sending IGMP joins for the same group for which PIM joins are received
c) Exact trigger is unknown at this point, could be the remote receivers (which result in PIM joins)
flapping



Workaround:
Workaround is to force the PIM join to come in via another path to the affected switch or to clear IGMP
groups (clear ip igmp groups *)

Issue is related to pim join packet having first group with zero joins and prunes which causes nxos
pim code to reject whole packet as invalid even other group included in it have non zero joins or
prunes.

Group 0: 226.124.124.19/32
Join: 0< ==
Prune: 0< ==
Group 1: 226.124.124.20/32
Join: 1
IP address: 124.124.124.124/32 (SWR)
Many more articles to come so ....

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