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Cisco Bug: CSCtf40289 - BGP NSR session not established on standby RP

Last Modified

Mar 06, 2018

Products (1)

  • Cisco IOS

Known Affected Releases


Description (partial)


The BGP session configured for NSR using the "neighbor <ip-address> ha-mode sso" command inside an IPv4 VRF address-family fails to be synced to the standby unit of a dual-route processor router.


This issue is observed when the following conditions are met:

(1) The active route processor (RP) and the standby RP are both loaded and the router reaches hot standby state before any BGP configuration is applied (that is, no BGP configuration is saved in the router configuration).

(2) BGP is configured after step (1).

(3a) The Nonstop Routing (NSR) configuration is applied to the neighbor before the session is established and the session is opened actively by the PE (PE initiates the TCP connection and sends the first open message).


(3b) The session with the CE is established first and then the NSR configuration is subsequently applied to the neighbor.
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