Bay Networks 5393 Hardware Installation Manual page 120

Chapter 4 Troubleshooting Procedures
4-18 Remote Annex 5393/PRI Hardware Installation Guide
The supervisory module, located in slot 0 of the 5000 hub, performs
several functions for the hub and the modules installed in the hub.
The supervisory module stores the primary configurations of all
modules installed in the hub. Each user-installed module also stores
a working copy of its configuration information. When a change is
made to this working copy, the module stores the new user
configuration in its onboard nonvolatile memory.
The supervisory module periodically polls user-installed modules in
the hub across the common management bus (CMB). As part of the
poll, the NMM collects module configuration information and stores
the information in its local nonvolatile memory for use in comparing
and/or restoring a module configuration after a power cycle or reset.
What happens to a module when it is inserted in the hub depends on
a combination of conditions:
If you remove a module, change jumper settings, and reinsert
the module in its original slot, the new jumper settings take
effect immediately. The supervisory module records the new
configuration information in its nonvolatile memory.
If you replace a module in a slot with a different type of
module, the new module is directed to use its default
configuration.
If the supervisory module is not operational, a module
whose configured slot number matches its installed location
can use its own stored configuration; otherwise, the module
reverts to its default configuration.
To preserve the configuration parameters of the Remote Annex
module you are replacing, follow the procedures in
Swap on page 4-19 and
Verify that the backplane segment bank selector is set for the
correct segment bank before installing a replacement module.
For more information on jumper and switch settings, see
Chapter 2.
Completing the Hot Swap
Preparing for a Hot
on page 4-21.