Application Support For Stateful Line Module Switchover; Policy Management - Juniper JUNOSE SOFTWARE FOR E SERIES 11.3.X - SERVICE AVAILABILITY CONFIGURATION GUIDE 2010-10-08 Configuration Manual

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Application Support for Stateful Line Module Switchover

Policy Management

Copyright © 2010, Juniper Networks, Inc.
Application Support for Stateful Line Module Switchover on page 79
Log Messages Generated for Stateful LM Switchover on page 91
Monitoring the Redundancy Status of Line Modules in a Specific Slot on page 95
Monitoring the Redundancy History of Line Modules in a Specific Slot on page 97
Interoperation of Redundancy and Stateful Switchover for Line Modules on page 15
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Applications are either supported or unsupported by stateful line module switchover.
Supported—You can configure supported applications without having any adverse
impact to stateful line module switchover. When a switchover occurs, supported
applications can react to switchovers in one of two different ways:
Gracefully recover using mirrored static and dynamic information (for example, IP,
PPP, and PPPoE)
Recover using static configuration only; that is, no runtime state is restored after a
switchover. Dynamic configuration and state information are lost. (For example, CLI
sessions are restarted, telnet sessions are dropped, multicast routes must be rebuilt,
and so on.)
Unsupported—We recommend that you not configure unsupported applications on a
line module running in high availability mode. Although configured unsupported
applications suspend high availability or prevent high availability from becoming active,
they do not cause any problems with the function of the router.
The sections that follow describe the working behavior of applications that support
stateful line module switchover.
NOTE: Only the applications discussed in the sections that follow are
compatible with stateful line module switchover.
Because the policy application in the line module does not contain the complete state
of all the policy definitions in mirrored containers, the SRP module is used to download
the policy definitions and attachments to the newly active line module when a stateful
switchover occurs. The policy application sends multiple policy attachment requests
from the SRP module to the line module in a single notify operation and in a bulk manner,
instead of one policy attachment request in each notify event. This method of transferring
Chapter 4: Managing Stateful Line Module Switchover
79