Figure 7: Sre Module In An Ex8208 Switch - Juniper EX8208 Complete Hardware Manual

Copyright © 2010, Juniper Networks, Inc.
You can install one or two SRE modules in an EX8208 switch. A base configuration
EX8208 switch has only one SRE module. See "EX8208 Switch Configurations" on
page 7. You can add a second SRE module to the configuration for Routing Engine and
switch control redundancy. See "Understanding EX8208 Switch Component and
Functionality Redundancy" on page 11.
The SRE modules install horizontally into the front of the chassis in slots labeled SRE0
and SRE1.

Figure 7: SRE Module in an EX8208 Switch

NOTE: We recommend that you install two SRE modules for redundancy. If
you install only one SRE module, we recommend that you install it in slot
SRE0. See "Slot Numbering for an EX8208 Switch" on page 13.
If two SRE modules are installed, one functions as the master and the other acts as the
backup. If the master SRE module fails or is removed, the backup takes over as the master.
If two SRE modules are installed, the backup SRE module is hot-insertable and
hot-removable, but the master SRE module is hot-pluggable. If only one SRE module is
installed, you must halt the SRE module before removing it.
The SRE module provides these functions:
Provides full fabric connectivity to all line cards installed in the chassis
Through the switching plane, provides switching functionality to the switch
Powers the line cards on and off
Controls system resets and boot sequence for the switch
Monitors and controls the fan speed, power status for various chassis components,
LCD panel and chassis status LEDs
The SRE module has these components:
Chapter 2: Component Descriptions
27