Stack Redundancy; Stack Health; Overview; Implementation Of Stack Health In The P330 Family - Avaya P334T-ML Installation And Configuration Manual

Chapter 11 Avaya P330 Layer 2 Features

Stack Redundancy

In the unlikely event that a P330 switch or Octaplane link should fail, stack integrity
is maintained if the redundant cable is connected to the stack. The broken link is
bypassed and data transmission continues uninterrupted. The single management
IP address for the stack is also preserved for uninterrupted management and
monitoring. You can remove or replace any unit within the stack without disrupting
operation or performing stack-level reconfiguration.
Since each P330 module has an integral SNMP agent, any module in a stack can
serve as the stack Network Management Agent (NMA) while other NMAs act as
redundant agents in "hot" standby. If the "live" NMA fails then a backup is
activated instantaneously.

Stack Health

The P330 software provides a Stack Health feature for verifying the integrity of the
P330 stack cascading module and cables.

Overview

The Stack Health feature will identify defective modules and cables that may be
installed in the P330 stack. The Stack Health algorithm separately checks all stacking
modules and the Octaplane connections (including Redundant cable).

Implementation of Stack Health in the P330 Family

When activating the Stack Health feature, the agents in all modules start sending
special packets of various length via all stacking cables to one another. The Master
module synchronizes this process and collects the results.
• When the Redundant Cable is present, the user is prompted to disconnect one
of the short Octaplane cables and the redundant connection will be checked.
Then, when prompted, the cable should be reconnected and the test will run a
second time to check the regular Octaplane connections.
• The stack is reset after the Stack Health process completes.
You should not load the stack with traffic during this test.
If the stack health process fails, try to fasten or replace the stack cable between
the modules where the failure has occurred. If the problem persists, try to fasten
or replace either or both of the stacking modules.
116 Avaya P334T-ML User's Guide