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Cisco Bug: CSCvv40252 - TCP SYN dropped on established connection for telemetry/TPA session

Last Modified

Oct 24, 2020

Products (1)

  • Cisco ASR 9000 Series Aggregation Services Routers

Known Affected Releases


Description (partial)

Regular inbound telemetry probes intermittently fail for a small number of particular TCP ports.
tcpdump of connection during failure shows repeated SYNs being sent for the same port, but no response from the router.

Could impact any TCP session to TPA application (e.g. telemetry)
Only seen when there are stale TCP sessions in TPA. This may be caused by RPFO or by a s/w reload of IOS-XR (reload location all).
Existing TCP sessions can be checked using netstat from bash.
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Bug Details Include

  • Full Description (including symptoms, conditions and workarounds)
  • Status
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