Conventions; Vss Deployment Best Practices; Vss High Availability - Cisco Catalyst 6500 User Manual

Conventions

Refer to Cisco Technical Tips Conventions for more information on document conventions.

VSS Deployment Best Practices

The solutions that this document offers represent years of field experience from Cisco engineers who work
with complex networks and many of the largest customers. Consequently, this document emphasizes
configurations that make networks successful. This document offers these solutions:
•
Solutions that are easy to manage and that network operations teams configure
•
Solutions that promote high availability and high stability

VSS High Availability

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Non Stop Forwarding
•
OOB MAC Synchronization
Non Stop Forwarding
Catalyst 6500 series switches support fault resistance, because it allows a redundant supervisor engine to take
over if the primary supervisor engine fails. Cisco Non Stop Forwarding (NSF) works with Stateful
SwitchOver (SSO) in order to minimize the amount of time a network is unavailable to its users after a
switchover while IP packets continue to be forwarded.
Recommendations
•
Non Stop Forwarding is required for supervisor switchover convergence at sub−second time.
•
Use default Hello and Dead timers for EIGRP / OSPF protocols when you run in a VSS environment.
•
If you run the system with modular Cisco IOS software, it is recommended to go for larger value
OSPF Dead timer.
EIGRP
Switch(config)# router eigrp 100
Switch(config−router)# nsf
Switch# show ip protocols
*** IP Routing is NSF aware ***
Routing Protocol is "eigrp 100"
!−−− part of the output truncated
EIGRP NSF−aware route hold timer is 240s
!−−− indicates that EIGRP is configured to be NSF aware
!−−− part of the output truncated
EIGRP NSF enabled
!−−− indicates that EIGRP is configured to be NSF capable
!−−− rest of the output truncated