Juniper Networks E-Series - Manual (Page 38)

CHAPTER 1
E-Series Overview 1-16
NMC-RX Device Management System
The NMX-RX application provides a global method of managing all
routers, line modules, and ports through a graphical user interface.
Redundancy Features
The system has the following redundancy features:
SRP Modules
Note: This section applies to ERX-7xx/14xx models only. ERX-310 routers contain
one SRP module and therefore do not offer SRP module redundancy.
ERX-7xx/14xx models use a 1:1 redundancy scheme for the SRP module.
When two SRP modules of the same type are installed in the chassis, one
acts as a primary and the second as a standby. Both SRP modules share a
single SRP I/O module located in the rear of the chassis. If the primary
SRP fails, the redundant SRP module assumes control without rebooting
or initializing. (As a consequence, if you upgrade software, you must copy
the software to the redundant SRP and reboot it.) For information about
configuring and managing SRP module redundancy, see the
E-Series
System Basics Configuration Guide, Chapter 5, Managing Line Modules
and SRP Modules
.
After you install two SRP modules, the modules negotiate for the primary
role. A number of factors determine which module becomes the primary;
however, preference is given to the module in the lower-numbered slot.
The SRP modules record their latest roles and retain them the next time
you switch on the system. For information about installing SRP modules,
see
Chapter 5, Installing Modules .
NVS Cards
If you have two SRP modules installed in a system, you can use NVS
cards of different capacities on the SRP modules. The effective capacity
of the higher-capacity NVS card will equal that of the lower-capacity
NVS card. For information about installing NVS cards, see
Chapter 5,
Installing Modules .
When you install new NVS cards or SRP modules, you must issue the
synchronize command to match the file system of the NVS card on the
redundant SRP module with the file system of the NVS card on the
primary SRP module. (The NVS card on the redundant SRP module will
hereafter be referred to as the redundant NVS card; the NVS card on the