ISSUs

Upgrading in-service NEs

CAUTION Service Disruption

Before you attempt an ISSU, see the appropriate device release notice and the NSP NFM-P Network Element Compatibility Guide for information about the following:

• device releases that support ISSU

• supported upgrade paths

The software upgrade information in the device documentation takes precedence over the information in this chapter.

You can use the NFM-P to perform an in-service software upgrade, or ISSU, on a managed NE that has dual CPMs. An ISSU allows an NE to provide uninterrupted service during the upgrade process.

A device software upgrade requires a CPM restart, which causes a temporary NE outage. When an NE has dual CPMs, however, one CPM can remain active while the other restarts using the upgraded software. The alternate CPM restarts mean that the NE remains fully in service during an upgrade. If the upgrade of a CPM fails, the CPM reports the failure and an alarm is raised.

Note: ISSUs are restricted to device maintenance releases only. See the device documentation for the supported release transitions.

Some 7210 SAS chassis types do not support ISSUs; see the device documentation for more information.