[c-nsp] issu on ios-xr

Oliver Boehmer (oboehmer) oboehmer at cisco.com
Tue Dec 9 01:33:30 EST 2008

Marlon Duksa <> wrote on Monday, December 08, 2008 23:17:

> Hi - does IOS-XR supports STATEFUL switchover of control plane? There
> is a bunch of reference to this (RSP SSO, NSF, NSR, Gracefull
> Restart) but it is not clear to me simply whether are protocol states
> replicated to the standby RSP?
> I'm not looking for GR protocol extensions in conjunction with NSF to
> provide control plane redundancy but rather a true state replication.
> For example if BGP goes down, the TCP session will never be broken
> between the peers.
> If this is supported, how is it called in Cisco's terms?  

What you are looking for is referred to as "NSR" (Non-Stop Routing). The
standby RP has all the required state to resume operation without any
help from peers (unlike NSF/GR). I think we ship it now for LDP and OSPF
(ISIS "nsf cisco" has always been acting pretty much like NSR, not
requiring neighbor awareness), BGP will come soon.


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