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Cisco Bug: CSCvu79503 - Traffic black-holing due to routes missing in RIB

Last Modified

Aug 26, 2020

Products (1)

  • Cisco Nexus 9000 Series Switches

Known Affected Releases

9.3(4)

Description (partial)

Symptom:
Summary of symptoms:
After continuous route flap in high prefix scale, BGP does not install some routes in URIB.
Detailed symptoms:
1. BGP routes reachable via a particular RNH (lets say e.f.g.h/n) are not installed in URIB.
2. All BGP routes with that particular RNH are marked invalid with "inaccessible nexthop" reason in BGP table.
3. URIB throws the following message:
 %URIB-3-ADD_RPATH:  urib [xxxxx] (default-base) Client "bgp-yyyyy" added a.b.c.d/n via not found rnh e.f.g.h/n%default
4. Route for RNH not present for recursive next-hop RIB confirmed using below command:
# sh routing recursive-next-hop e.f.g.h/n
IP Recursive Next-Hop Table for VRF "xxxxx"
Virtual next-hop not found <<< Nothing here

Conditions:
1. BGP prefix scale exceeding 100,000.
2. All these routes are continuously flapped, leading to BGP continuously installing and removing these routes in URIB over and over.
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Bug Details Include

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