Configuring Is-Is Gr; Establishing The Configuration Task - Huawei S6700 Series Configuration Manual

S6700 Series Ethernet Switches
Configuration Guide - IP Routing

6.16 Configuring IS-IS GR

By configuring IS-IS GR, you can enable Switch to restart gracefully and avoid temporary black
holes.

6.16.1 Establishing the Configuration Task

Before configuring IS-IS GR, familiarize yourself with the applicable environment, complete
the pre-configuration tasks, and obtain the required data. This can help you complete the
configuration task quickly and accurately.
Applicable Environment
The restart of an IS-IS router causes the temporary interruption of the network, because the
adjacency relationship between the switch and its neighbor is torn down. The LSPs packets of
the switch are deleted, which makes route calculation inaccurate. Packets are thus lost.
You can configure IS-IS GR to solve this problem. After IS-IS GR is enabled, the switch notifies
the neighbor of the restart status, and reestablishes the adjacency relationship with its neighbor
without interrupting the forwarding.
The advantages of IS-IS GR are as follows:
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Pre-configuration Tasks
Before configuring IS-IS GR, complete the following tasks:
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Data Preparation
To configure IS-IS GR, you need the following data.
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Issue 01 (2012-03-15)
When IS-IS restarts, the switch can resend connection requests to its neighbor. The
adjacency relationship is not torn down.
Before LSPs packets are generated, GR minimizes the interference caused by waiting for
the database synchronization.
If the switch starts for the first time, the switch sets the overload bit in LSPs until the LSDB
synchronization is complete. This avoids route black holes.
Configuring IP addresses for interfaces to ensure network connectivity between
neighboring nodes.
Configuring Basic IPv4 IS-IS Functions
Data
ID of an IS-IS process
Interval for reestablishing GR sessions
Whether to suppress the advertisement of the adjacency when the GR restarter restarts
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