Understanding Ex9253 Switch Component And Functionality Redundancy - Juniper EX9253 Hardware Manual

Table 6: LEDs on the Routing Engines in an EX9253 Switch
LED
Link LED on the BITS port
Understanding EX9253 Switch Component and Functionality
Redundancy
The Juniper Networks EX9253 Ethernet Switches are available as fully redundant system. A redundant
EX9253 switch configuration is designed so that no single point of failure can cause the entire switch to
fail. See "EX9253 Switch Configurations" on page
The following hardware components provide redundancy to an EX9253 switch:
• Host Subsystem—The host subsystem provides switching protocol processes as well as software
processes that control the switch' s interface, the chassis components, system management, and user
access to the switch. These switching processes run on top of a kernel that interacts with the Packet
Forwarding Engine. The host subsystem consists of two Routing Engines (REs). The RE is an
integrated board that provides Routing Engine and Control Board functionality and supports
virtualization. If two REs are installed, one functions as the primary and the other functions as the
backup. If the primary host subsystem (or either of its components) fails, the backup can take over as
the primary.
If the Routing Engines are configured for graceful switchover, the backup Routing Engine
automatically synchronizes its configuration and state with the primary Routing Engine. Any update
to the primary Routing Engine state is replicated on the backup Routing Engine. If the backup
Routing Engine assumes primary role, packet forwarding continues through the switch without
interruption. See "Host Subsystem in an EX9253 Switch" on page
• Power supplies—The switch supports six power supplies, installed on the rear panel of the chassis in
slots PEM0 through PEM5 (left to right). In a switch powered by AC power supplies, a minimum of
Color
–
Amber
–
7.
(Continued)
State
Off
On steadily
Off
15.
Description
There is loss of signal or
loss of line.
There is loss of signal or
loss of line.
There is no loss (BITS is in
locked state).
20