Configuring A Preference Value For Ipv4 Is-Is - Huawei Quidway NetEngine80E Configuration Manual

HUAWEI NetEngine80E/40E Router
Configuration Guide - IP Routing
l
Pre-configuration Tasks
Before configuring IPv4 IS-IS to interact with other routing protocols, complete the following
tasks:
l
l
l
l
Data Preparation
To configure the IPv4 IS-IS route convergence speed, you need the following data.
No.
1
2

7.6.2 Configuring a Preference Value for IPv4 IS-IS

If multiple routes to the same destination are discovered by different routing protocols,
configuring the highest preference value for IS-IS allows a route discovered by IS-IS to be
selected preferentially.
Issue 02 (2014-09-30)
If multiple routes to the same destination are discovered by different routing protocols
running on the same device, the route discovered by the protocol with the highest preference
is selected. For example, if both OSPF and IS-IS are configured, the route discovered by
OSPF is used because OSPF enjoys a higher preference than IS-IS by default.
Therefore, if you want the route discovered by IS-IS to be used, configure IS-IS to have
the highest preference.
Communication between an IS-IS area and other areas
If other routing protocols are configured on an IS-IS network, you need to configure IS-IS
to interact with those routing protocols so that IS-IS areas can communicate with non-IS-
IS areas.
NOTE
The LSDBs of different IS-IS processes on a device are independent of each other. Therefore, each
IS-IS process on the device considers routes of the other IS-IS processes as external routes.
To ensure successful traffic forwarding, configure IS-IS to interact with other routing
protocols on a device where external routes are configured, for example, a Level-1-2 IS-
IS router. Available method is configuring IS-IS to import external routes. This mode
enables all devices in IS-IS areas to learn external routes, implementing refined control
over traffic forwarding.
To ensure successful forwarding of traffic destined for IS-IS areas, you must also enable
the other routing protocols to interact with IS-IS.
Configuring the link layer protocol on interfaces
Configuring IP addresses for interfaces to ensure that neighboring nodes are reachable at
the network layer
Configuring Basic IPv4 IS-IS Functions
Configuring basic functions of other routing protocols
Data
ACL for filtering routes, IP prefix list, or routing policy
Preference value of IS-IS
Huawei Proprietary and Confidential
Copyright © Huawei Technologies Co., Ltd.
7 IS-IS Configuration
540