Understanding Redundancy For The Routing Engine, Host Module, And Host Subsystem; M10I Router Redundant Routing Engines And Hcms - Juniper JUNOS - NETWORK OPERATION GUIDE REV1 Network Operation Manual

Understanding Redundancy for the Routing Engine, Host Module, and Host
Subsystem
To learn how redundant Routing Engines, host modules, and host subsystems work
Purpose
on various routing platforms. You monitor these components to provide a standby
Routing Engine and controller component that will switch from standby to active,
assuming mastership when a failure brings down the active master Routing Engine.
Redundant Routing Engines are two Routing Engines that are installed in the same
What Is a Routing
Engine, Host Module, routing platform. One functions as the master, while the other stands by as a
and Host Subsystem
backup should the master Routing Engine fail. (See "M10i Router Redundant
Redundancy
Routing Engines and HCMs" on page 465 and "M20 Router Redundant Routing
Engines and SSBs" on page 466.)
Redundant host modules are two Routing Engine and Miscellaneous Control
Subsystem (MCS) pairs installed in the same routing platform. One pair functions as
master, while the other stands by as a backup should the master Routing Engine
fail. (See "M40e and M160 Router Redundant Host Modules" on page 467.)
Redundant host subsystems are two Routing Engine and Control Board pairs
installed in the same routing platform. One pair functions as master, while the
other stands by as backup should the master Routing Engine fail. (See "M320
Router, T320 Router, and T640 Routing Node Redundant Host Subsystems" on
page 468.)
The M5, M10, M7i, and M40 routers do not support Routing Engine, host module,
or host subsystem redundancy.

M10i Router Redundant Routing Engines and HCMs

On the M10i router, the High-Availability Chassis Manager (HCM) works with its
companion Routing Engine to provide control and monitoring functions for router
components. The router can have one or two HCMs and Routing Engines. (See
Figure 183 and "Redundancy Connection for an M10i Router" on page 470.)
Figure 183: M10i Router Redundant Routing Engines and HCMs
HCM0
HCM1
HCMs

Understanding Redundancy for the Routing Engine, Host Module, and Host Subsystem

Chapter 36: Host Redundancy Overview
RE0
RE1
Routing Engines
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465