Line Modules

Note: This section applies to ERX-7xx and ERX-14xx models only. ERX-310 routers do not offer line module redundancy.

ERX-7xx and ERX-14xx models support line module redundancy for several line modules. For details about which line modules support redundancy, see the ERX Module Guide. In this scheme, an extra line module in a group of identical line modules provides redundancy in case of line module failure. To use this feature, you need a:

• Spare line module
• Redundancy midplane
• Redundancy I/O module

A redundancy midplane can cover 3–6 slots. It provides additional connectivity that enables the spare line module to take control of the I/O module associated with any failed line module in the redundancy group. The spare I/O module provides connectivity from the spare line module to the redundancy midplane.

The process by which the system switches to the spare line module is called switchover. When switchover occurs, the system:

1. Breaks the connection between the primary I/O module and the primary line module.
2. Connects the primary I/O module to the spare line module via the redundancy midplane and redundancy I/O module.

Protocol processing then takes place on the spare line module.

Figure 12 shows the data flow when a spare line module becomes active.

Figure 12: Data Flow When a Spare Line Module Is Active

For information about installing modules for line module redundancy, see Installing Modules. For information about configuring and managing SRP module redundancy, see JUNOSe System Basics Configuration Guide, Chapter 6, Managing Modules.

Copyright © 2008, Juniper Networks, Inc. All rights reserved. Trademark Notice.