Nortel 5399 Hardware Installation Manual page 110

Chapter 4 Troubleshooting Procedures
Nortel Networks 5399 Access Switch Hardware Installation Guide
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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.