Nsf Guidelines And Restrictions - Cisco Catalyst 4500 Series Configuration Manual

Chapter 11 Configuring Cisco NSF with SSO Supervisor Engine Redundancy
When the restarting router has received all EOT indications from its neighbors or when the NSF converge
timer expires, EIGRP notifies the RIB of convergence. EIGRP waits for the RIB convergence signal and
then floods its topology table to all awaiting NSF-aware peers.

NSF Guidelines and Restrictions

NSF with SSO has these restrictions:
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Configuring NSF with SSO Supervisor Engine Redundancy
The following sections describe the configuration tasks for the NSF feature:
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OL-25340-01
With aggressive protocol timers (such as, when the default exceeds the timer value), upon
switchover, the protocol software running on the new active supervisor engine might not initialize
in time to send "hello" packets to its neighboring switches or routers. If the protocol takes longer
time to initialize because of other CPU-demanding tasks, then the protocol encounters state
transitions and causes a loss in traffic on the order of seconds. We recommend that you do not
configure aggressive timers in conjunction with SSO/NSF.
For NSF operation, you must have SSO configured on the device.
NSF with SSO supports IP Version 4 traffic and protocols only; NSF with SSO does not support IPv6
traffic.
The Virtual Redundancy Routing Protocols (VRRP) is not SSO-aware, meaning state information is
not maintained between the active and standby supervisor engine during normal operation. VRRP
and SSO can coexist but both features work independently. Traffic that relies on VRRP may switch
to the VRRP standby in the event of a supervisor engine switchover.
All neighboring devices participating in BGP NSF must be NSF-capable and configured for BGP
graceful restart.
OSPF NSF for virtual links is not supported.
All OSPF networking devices on the same network segment must be NSF-aware (running an NSF
software image).
For IETF IS-IS, all neighboring devices must be running an NSF-aware software image.
Configuring SSO, page 11-10
Configuring CEF NSF, page 11-10
Verifying CEF NSF, page 11-11
Configuring BGP NSF, page 11-11
Verifying BGP NSF, page 11-11
Configuring OSPF NSF, page 11-12
Verifying OSPF NSF, page 11-13
Configuring IS-IS NSF, page 11-13
Verifying IS-IS NSF, page 11-14
Configuring EIGRP NSF, page 11-16
Verifying EIGRP NSF, page 11-16
Configuring NSF with SSO Supervisor Engine Redundancy
Software Configuration Guide—Release IOS XE 3.3.0SG and IOS 15.1(1)SG
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