7.15 Configuring IPv6 IS-IS to Interact with Other Routing
Protocols
If other routing protocols are configured on an IS-IS network, you need to configure IS-IS to
interact with these protocols to ensure successful communication between them.
7.15.1 Before You Start
Before configuring IPv6 IS-IS to interact with other routing protocols, familiarize yourself with
the usage scenario, complete the pre-configuration tasks, and obtain the data required for the
configuration.
Applicable Environment
If other routing protocols are configured on an IS-IS network, the following issues need to be
considered:
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Preference of IS-IS routes
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 OSPFv3 and IS-IS are configured, the route discovered
by OSPFv3 is used because OSPFv3 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.
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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.
Pre-configuration Tasks
Before configuring IPv6 IS-IS to interact with other routing protocols, complete the following
tasks:
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Configuring the link layer protocol on interfaces
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Configuring IP addresses for interfaces to ensure that neighboring nodes are reachable at
the network layer
HUAWEI NetEngine80E/40E Router
Configuration Guide - IP Routing
7 IS-IS Configuration
Issue 02 (2014-09-30)
Huawei Proprietary and Confidential
Copyright © Huawei Technologies Co., Ltd.
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