Juniper Networks ERX-1410 - Manual (Page 33)

Redundancy Features
ERX Edge Routers
1-13
If there is not enough space on the primary NVS card to create the
synchronization reserve file, the
synchronize command fails, and you
see a warning message on the console. To resolve this issue, either delete
unwanted files from the primary NVS card or replace the redundant
NVS card with a higher-capacity NVS card.
Line Modules
The ERX system supports line module redundancy for several line
modules. For details about which line modules support redundancy, see
Appendix B, Module Specifications . In this scheme, an extra line access
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 may cover 2–6 slots. It provides additional
connectivity that enables the spare line module to assume 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 1-10 shows the data flow when a spare line module becomes
active.