# Unified ISSU Service Restoration Phase Overview

This is the final unified ISSU phase. At this point, all three major components of the router—the SRP modules, the line module control planes, and the line module forwarding planes—have been upgraded and forwarding has resumed through the chassis. The following actions take place during this phase:

- The CLI is re-enabled. All commands are made available to users.
- The SNMP agent is restarted and bulk statistics are collected and available for review. (The first interval of bulk statistics collection starts when unified ISSU is still in process. Therefore, the system performs bulk statistics collection after the first interval.)
- New login requests and logout requests are processed. The router begins to accept externally created events from sources other than the CLI and SNMP. These events typically come from user connections, RADIUS servers, and SRC software and SDX software, and include login requests, COA requests, multicast join requests, and so on.
- Logout requests that were cached at the start of the unified in-service software upgrade are processed.
- After the flash memory on the newly active SRP module is updated, stateful SRP switchover is available to the router.

At this point the unified in-service software upgrade is completed, and the router is restored to normal operation. Any line modules that reloaded during the upgrade phase and were therefore held down are now rebooted to the original running release.

#### Related Documentation

- Unified ISSU Phases Overview