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Cisco Bug: CSCut65950 - Border leaf iBGP route flapping when it loses all its external links

Last Modified

Nov 27, 2018

Products (1)

  • Cisco Nexus 9000 Series Switches

Known Affected Releases


Description (partial)

When border leaf BL201 loses both its links to external CI1 and CI2 (shut down from CIx side), we observed on BL1 that the the OSPF converges but the BGP route for external destination was flapping between next hop of (BL202 overlay-1/VTEP IP) and and .2 (looked like due to recursive lookup for and .2), and blackholing egress traffic for up to 180 seconds until BGP peering with CI1 and CI2 times out and route converges and back to stable condition.

iBGP is configured for L3-Out connection and border leaf loses all its external connections.
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