Cisco Cisco IOS Software Release 12.0(23)S
Stateful Switchover
3
Cisco IOS Release 12.0(23)S
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.
a switchover or a planned software upgrade, enterprise customer sessions would continue uninterrupted
through the network.
Figure 2
Cisco NSF with SSO Network Deployment: Enterprise Networks
Redundancy Modes
SSO is one link in a chain of Cisco IOS redundancy features designed to provide progressively higher
system and network availability. The specific configuration running on the networking device identifies
Cisco IOS redundancy modes, which are described in the following sections:
system and network availability. The specific configuration running on the networking device identifies
Cisco IOS redundancy modes, which are described in the following sections:
•
High System Availability
•
Route Processor Redundancy
•
Route Processor Redundancy Plus
•
Stateful Switchover
Understanding the various modes is helpful in configuring and verifying SSO.
indicates which
redundancy modes are supported on various platforms and releases.
Service
provider
core
layer
Service provider
distribution
layer
Service
provider
provider
access layer
Enterprise
access
layer
Enterprise
distribution
layer
Enterprise
core
layer
Good position for
NSF-aware
routers
Good position for
NSF-aware
routers
Primary deployment
position for Cisco NSF
with SSO-capable routers
Secondary deployment
position for Cisco NSF
position for Cisco NSF
with SSO-capable
or -aware routers
SSO may provide
some benefit
72064
Cisco NSF with SSO
features may provide
features may provide
some benefit, but usually
not required