Graceful Insertion and Removal (GIR) isolates a switch from the network in order to perform debugging or an upgrade. When
switch maintenance is complete, the switch will return to normal mode on either reaching the configured maintenance timeout,
or by enabling the stop maintenance command.
A switch can be put into maintenance mode using default template or a custom template. The default template contains all the
ISIS instances, along with shut down l2 . In the custom template, you can configure the required ISIS instances and shutdown l2 option. On entering maintenance mode, all participating protocols are isolated, and L2 ports are shut down. When normal mode
is restored, all the protocols and L2 ports are brought back up.
Creating a maintenance mode template before you put the switch in maintenance mode is optional. The objective of maintenance
mode for a device is to minimize traffic disruption at the time of removal from the network, as well as during the time of
insertion. There are mainly three stages:
Graceful removal of the node from network.
Performing maintenance on the device.
Graceful insertion into the network.
Snapshots are taken automatically while entering and exiting the maintenance mode. You can use the snapshot create snapshot-name snapshot-description command to capture and store snapshots for pre-selected features. Snapshots are useful to compare the state of a switch before
it went into maintenance mode and after it came back to normal mode. The snapshot process consists of three parts:
Creating a snapshot of the states of a few preselected features on the switch and storing them onthe persistent storage media.
Listing the snapshots taken at various time intervals and managing them.
Comparing snapshots and showing the summary and details of each feature.
The maximum number of snapshots that may be stored on the switch is 10. You can use the command snapshot delete snapshot-name to delete a specific snapshot from the device.