MPX Redundancy
Page 2-9

MPX Redundancy

In order to provide greater reliability, Omni Switch/Router supports two MPXs in a
primary/secondary redundant configuration. If the primary MPX fails, the secondary MPX takes
over without any operator intervention.
♦ Warning ♦
Do not install any version of the MPM (i.e, MPM-C,
MPM 1G, MPM II, or original MPM) in a chassis with an
MPX. Installing an MPM in a chassis with an MPX can
cause physical damage. If you want to configure an
Omni Switch/Router chassis in a redundant configura-
tion, you must use two MPXs.
When you have two MPXs in one chassis, they must be installed in Slots 1 and 2, and only
one can be active. MPXs will assume one of the following roles.
• Primary - The MPX that is currently active and processing commands. It is also the MPX that
is communicating via Telnet, FTP, etc.
• Secondary - An MPX that is currently not the primary. It has sufficient software to commu-
nicate with the primary MPX. (For full redundancy, the secondary MPX should also have
the same software version as the primary and its configuration should be in sync with the
primary.) In this state, it is capable at any time of assuming the primary role.
The LEDs on each MPX reflect the same status with the exception that the primary’s PRI LED is
on whereas the secondary’s SEC LED is on. Also, the secondary MPX’s OK2 LED will not flash
amber during board transitions. See Omni Switch/Router Management Processor Module
(MPX) Status LEDs on page 2-2 for locations of the LEDs.
♦ Important Note ♦
To support redundancy, your MPX must be Revision
A14 or higher.

Change-Over Procedure

The secondary MPX continuously monitors the primary MPX. This monitoring serves two
purposes: 1) to notify the secondary MPX that the primary is alive and processing, and 2) to
update the configuration and thus keep the two MPXs in sync. If the secondary MPX detects
that the primary is no longer operational, it will begin to take over as primary. When a
secondary MPX becomes primary it resets all the other modules in the chassis and performs a
primary MPX initialization.
There are four states for an MPX configuration. You can view the current MPX state through
the slot command. These states are described in the table below. Note that for a
primary/secondary configuration to be in a “redundant” state, the relationship between the
two MPXs must meet the conditions shown in the table.