Cisco Catalyst 4500 Series Configuration Manual page 252

About Performing ISSU
For Cisco NSF protocols that require neighboring devices to participate in Cisco NSF, Cisco NSF-aware
software images must be installed on those neighboring distribution layer devices. Depending on your
objectives, you may decide to deploy Cisco NSF and SSO features at the core layer of your network.
Doing this can help reduce the time required to restore network capacity and service for certain failures,
which leads to additional availability.
Figure 6-1
Service
provider
core
layer
Service provider
distribution
layer
Service
provider
access layer
Additional levels of availability may be gained by deploying Cisco NSF with SSO at other points in the
network where a single point of failure exists.
applies Cisco NSF with SSO at the enterprise network access layer. In this example, each access point
in the enterprise network represents another single point of failure in the network design. In the event of
a switchover or a planned software upgrade, enterprise customer sessions would continue uninterrupted
through the network in this example.
Software Configuration Guide—Release IOS XE 3.3.0SG and IOS 15.1(1)SG
6-4
Chapter 6
Cisco NSF with SSO Network Deployment: Service Provider Networks
Customers
Configuring the Cisco IOS XE In Service Software Upgrade Process
Cisco NSF with SSO
features may provide
some benefit, but usually
not required
Good position for
NSF-aware
routers
Primary deployment
position for Cisco NSF
with SSO capable-routers
Figure 6-2 illustrates an optional deployment strategy that
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