Host Subsystem in an EX9200 Switch
Switching and roung funconality, system management, and system control funcons of an EX9200
switch are performed by host subsystem. A host subsystem consists of a Roung Engine funconing
together with a Switch Fabric.
You can install either one or two host subsystems in the front panel of an EX9204 or an EX9208 switch.
A base conguraon EX9204 and EX9208 switch has one host subsystem. A redundant conguraon
EX9204 and EX9208 switch has a second host subsystem.
You can install either two or three host subsystems in the front panel of an EX9214 switch. A base
conguraon EX9214 switch has two host subsystems. A redundant conguraon EX9214 switch has a
third host subsystem.
NOTE: In EX9204 and EX9208 switches, we recommend that you install two host subsystems
for redundant protecon. If you install only one host subsystem, we recommend that you install
it in slot 0. In EX9214 switches, we recommend that you install three host subsystems for
redundant protecon. If you install only two host subsystems, we recommend that you install it
in slot 0 and 1.
Each host subsystem has LEDs in the cra interface that display its status. See "Cra Interface in an
EX9200 Switch" on page 29.
SEE ALSO
Taking the Host Subsystem Oine in an EX9200 Switch
Maintaining the Host Subsystem in EX9200 Switches
Roung Engine Module in an EX9200 Switch
The Roung Engine module (RE module) is an Intel-based plaorm that runs Juniper Networks Junos
operang system (Junos OS). Soware processes that run on the RE module maintain the roung tables,
manage the roung protocols used on the switch, control the router interfaces and some of the chassis
components, and provide the interface for system management and user access to the switch.
In an EX9204, EX9208, or EX9214 switch, you can install one or two RE modules in the Switch Fabric
modules (SF modules) that are installed in slots on the front panel of the switch. If you install two RE
modules, one funcons as the primary and the other funcons as the backup. If the primary RE module
fails or is removed and the backup is congured appropriately, the backup takes over as the primary. The
60