Configuring Nonstop Forwarding (Nsf); Configuring Cef Nsf; Configuring Bgp Nsf - Cisco RSP2 - Route Switch Processor 2 Installation And Configuration Manual

Configuring NonStop Forwarding (NSF)

Cisco NonStop Forwarding (NSF) always runs together with SSO. If you have not already configured
SSO, refer to
the BGP, OSPF, and IS-IS protocols for routing and by Cisco Express Forwarding (CEF) for forwarding.
Of the routing protocols, BGP, OSPF, and IS-IS have been enhanced with NSF-capability and awareness,
which means that routers running these protocols can detect a switchover and take the necessary actions
to continue forwarding network traffic and to recover route information from the peer devices. The IS-IS
protocol can be configured to use state information that has been synchronized between the active and
the standby RSP to recover route information following a switchover instead of information received
from peer devices.
A device is said to be NSF-capable if it has been configured to support NSF; therefore, it would rebuild
routing information from NSF-aware or NSF-capable neighbors.
Each protocol depends on CEF to continue forwarding packets during switchover while the routing
protocols rebuild the Routing Information Base (RIB) tables. Once the routing protocols have converged,
CEF updates the FIB table and removes stale route entries. CEF, in turn, updates the line cards with the
new FIB information.
See the following sections for the NSF feature. Each task in the list is identified as either required or
optional.
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Configuring CEF NSF

The CEF NSF feature operates by default while the networking device is running in SSO mode. No
configuration is necessary.

Configuring BGP NSF

You must configure BGP graceful restart on all peer devices participating in BGP NSF.
Note
To configure BGP for NSF, use the following commands beginning in privileged EXEC mode, and repeat
this procedure on each of the BGP NSF peer devices:
OL-4923-01 B0
"Configuring a Stateful Switchover (SSO)" section on page
Configuring CEF NSF, page 49
Configuring BGP NSF, page 49
Configuring OSPF NSF, page 50
Configuring IS-IS NSF, page 50
Verifying CEF NSF, page 51
Verifying BGP NSF, page 52
Verifying OSPF NSF, page 52
Verifying IS-IS NSF, page 53
Troubleshooting NSF Features, page 54
Configuring BGP NSF Example, page 55
Configuring BGP NSF Neighbor Device Example, page 55
Configuring OSPF NSF Example, page 55
Configuring IS-IS NSF Example, page 56
(required)
(required)
(required)
(required)
(optional)
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(optional)
46. Cisco NSF is supported by
(optional)
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