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Cisco Bug: CSCvu37535 - NCS6000 : CSI interface is flapping ~300ms during RPFO causing isis adjacency flap and traffic drop.

Last Modified

Aug 16, 2020

Products (1)

  • Cisco ASR 9000 Series Aggregation Services Routers

Known Affected Releases


Description (partial)


CSI interface flap is seen during SDR XR-VM switchover. 
Following IOS messages can be seen on XR console when the issue is hit:

RP/B0/CB0/CPU4:2020 May 21 09:04:07.346 UTC: ifmgr[303]: %PKT_INFRA-LINK-3-UPDOWN : Interface CSI1, changed state to Down
RP/B0/CB0/CPU4:2020 May 21 09:04:07.526 UTC: ifmgr[303]: %PKT_INFRA-LINK-3-UPDOWN : Interface CSI1, changed state to Up

CSI is flapping for ~300ms due to which isis adjacency flapping over that csi interface and resulting in traffic drop for that duration.

This behavior observed on 2 csi interfaces.

SDR (XR-VM) switchover is triggered under high scale configuration and feature set (breakdown given in 'Further Problem Description:' section) in carved SDRs. Issue is not hit on the SDR with relatively lower config scale on the same set up.
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