Cisco Cisco IOS Software Release 12.2(20)S

NSF must be configured on a networking device that has been configured for SSO.

On platforms supporting the Route Switch Processor (RSP), and where the CEF switching mode is 
configurable, configure distributed CEF (dCEF) switching mode using the ip cef distributed 
command.

The Hot Standby Routing Protocol (HSRP) is not supported with Cisco Nonstop Forwarding with 
Stateful Switchover. Do not use HSRP with Cisco Nonstop Forwarding with Stateful Switchover.

All neighboring devices participating in BGP NSF must be NSF-capable, having been configured 
for BGP graceful restart as described in the “

” section.

All neighboring devices participating in EIGRP NSF operation must be NSF-capable or NSF-aware.

An NSF-aware router cannot support two NSF-capable peers performing an NSF restart operation 
at the same time. However, both neighbors will reestablish peering sessions after the NSF restart 
operation is complete.

OSPF NSF for virtual links is not supported.

All OSPF networking devices on the same network segment must be NSF-aware (that is, running an 
NSF software image).

OSPF NSF for sham links is not supported.

For IETF IS-IS, all neighboring devices must be running an NSF-aware software image.

The Cisco 7200 series router has a single CPU; therefore, it cannot support the stateful switchover 
in the event of a network processor engine (NPE) fault.

The Cisco 7206 does support NSF and can operate in a peer role with a Cisco 7500, 10000, or 12000 
series router running Cisco IOS Release 12.0(23)S. With NSF enabled, an RP switchover on the 
Cisco 7500, 10000, or 12000 series router peer should not cause a loss of PPP, ATM, high-level data 
link control (HDLC), or Frame Relay sessions, or a loss of any OSPF, BGP, or IS-IS adjacencies 
established between the Cisco 7200 and the peer.