Enabling Is-Is Gr; Configuring Parameters Of An Is-Is Gr Session - Huawei S6700 Series Configuration Manual

S6700 Series Ethernet Switches
Configuration Guide - IP Routing

6.16.2 Enabling IS-IS GR

Before configuring IS-IS GR, you need to enable the GR capability for IS-IS.
Context
Do as follows on the switch that runs IS-IS.
Procedure
Step 1 Run:
system-view
The system view is displayed.
Step 2 Run:
isis [ process-id ]
The IS-IS view is displayed.
Step 3 Run:
graceful-restart
IS-IS GR is enabled.
By default, IS-IS GR is disabled.
----End

6.16.3 Configuring Parameters of an IS-IS GR Session

By setting IS-IS GR parameters, you can avoid temporary black holes on the network.
Context
The switch that starts for the first time does not maintain the forwarding status. If the switch
restarts, the LSPs generated when the switch runs last time may exist in the LSDB of other
switches in the network.
The sequence number of an LSP fragment is reinitialized when the switch starts. Therefore, the
switch considers that the previously advertised LSP stored on other switches is newer than the
LSP generated locally after the switch starts. This leads to the temporary black hole in the
network, which lasts until the normal LSDB update process finishes. The switch then regenerates
its LSPs and advertises the LSPs with the highest sequence number.
When this switch starts, if the neighbor of the switch suppresses the advertisement of the
adjacency until this switch advertises the updated LSPs, the preceding case can thus be avoided.
Do as follows on the switch that runs IS-IS:
Procedure
Step 1 Run:
system-view
The system view is displayed.
Issue 01 (2012-03-15) Huawei Proprietary and Confidential
Copyright © Huawei Technologies Co., Ltd.
6 IS-IS Configuration
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