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External PIM BIDir Group Adversely Affecting ACI BL Leafs



We added an RP Candidate for a new PIM Bidirectional Multicast Group to our network. Upon doing this, our ACI infrastructure was adversely affected, particularly the Border Leafs. The PIM Processes crashed on both Border Leafs and six of our leaf switches. This brought down much of our Data Center Network until the the PIM BIDir RP Candidate and group address were removed. It's my understanding ACI does not support bidirectional PIM but looking at my L3Out interfaces, I see a label stating my neighbors are PIM BIDir capable. Should I have disabled the capability on my L3Out Neighbors? I'm still trying to figure out the correlation but the time of this change and the ACI outage correspond. Does anyone know where this file might've moved/archived to? /var/sysmgr/logs/1684947280_0x101_pim_log.22352.tar.gz  - I've logged into the switch and the directory is empty. Please see attachment. Has anyone had any problems with PIM BIDIR and their ACI Infrastructures? Thank you.


2 Replies 2

Robert Burns
Cisco Employee
Cisco Employee

If you get the crash dump to TAC they can decode & confirm, but this is likely a known PIM bug, fixed in 5.2 & later.  The bug manifests when an external RP address is changed (or possibly added).   As PIM BiDir isn't supported on ACI, you can disable this on the external device.  However, I don't believe that's the source of this issue.


Hi Robert,

Thank you for taking the time to respond. It's quite puzzling but I think you're right. Probably best we look into upgrade out of GP. 

Thank you Sir,


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