Interchassis Session Recovery - Cisco ASR 5000 Series Administration Manual

Interchassis Session Recovery

This chapter describes how to configure Interchassis Session Recovery (ICSR). The product Administration
Guides provide examples and procedures for configuration of basic services on the system. You should select
the configuration example that best meets your service model, and configure the required elements for that
model as described in the respective product Administration Guide, before using the procedures described
below.
Important
This chapter discusses the following:
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Overview
The ICSR feature provides the highest possible availability for continuous call processing without interrupting
subscriber services. ICSR allows the operator to configure geographically distant gateways for redundancy
purposes. In the event of a node or gateway failure, ICSR allows sessions to be transparently routed around
the failure, thus maintaining the user experience. ICSR also preserves session information and state.
ICSR is implemented through the use of redundant chassis. The chassis are configured as primary and backup,
with one being active and one standby. Both chassis are connected to the same AAA server. A checkpoint
duration timer controls when subscriber data is sent from the active chassis to the standby chassis. If the active
chassis handling the call traffic goes out of service, the standby chassis transitions to the active state and
continues processing the call traffic without interrupting the subscriber session.
ICSR is a licensed Cisco feature that requires a separate license. Contact your Cisco account representative
for detailed information on specific licensing requirements. For information on installing and verifying
licenses, refer to the Managing License Keys section of Software Management Operations.
Overview, page 333
ICSR Operation, page 339
Configuring ICSR, page 343
Troubleshooting ICSR Operation, page 358
Updating the Operating System, page 359
C H A P T E R
ASR 5500 System Administration Guide, StarOS Release 21.4
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