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Cisco Bug: CSCvi49894 - ISIS LSP regeneration after reload may take up to few seconds causing traffic black holing

Last Modified

Jan 18, 2019

Products (3)

  • Cisco Network Convergence System 5500 Series
  • Cisco Network Convergence System 5508
  • Cisco IOS XR Software

Known Affected Releases


Description (partial)

In the ungraceful condition - the reloading router re-flood its 'old lsp' (ie stale LSP with same sequence number) with OL bit set , Since SN is the same neighbours are ignoring this and not taking the OL bit setting, resulting in black holing. Eventually the reloading router corrects this by updating the SN, but for a period of time, up to ~6 seconds traffic is still sent being attracted to the reloaded router.  This behaviour needs to be fixed and the reloading router should generate its own LSP with higher SN

RP reload , including power failures
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