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Cisco Bug: CSCvt51424 - Local Microloop avoidance is overridden after local link down event

Last Modified

Sep 02, 2020

Products (6)

  • Cisco ASR 9000 Series Aggregation Services Routers
  • Cisco Network Convergence System 5516
  • Cisco Network Convergence System 5502-SE
  • Cisco Network Convergence System 5502
  • Cisco Network Convergence System 5501-SE
  • Cisco Network Convergence System 5501

Known Affected Releases


Description (partial)

ISIS microloop avoidance is not triggered by local link or BFD down event.

The problem happens under specific timing conditions, when updated LSP triggers SPF prior
the link or BFD down event is locally detected.

The problem is more likely to happen under following conditions:
- extremely aggressive initial LSP generation and SPF timers (example - both set to 1 ms)
- event happening on remote side (interface shutdown etc), and slow local failure detection (copper interfaces, subinterfaces with slow BFD, L1/L2 infrastructure in between routers, etc)
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Bug Details Include

  • Full Description (including symptoms, conditions and workarounds)
  • Status
  • Severity
  • Known Fixed Releases
  • Related Community Discussions
  • Number of Related Support Cases
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