No. Data
2 Maximum number of load-balancing equal-cost IS-IS routes
3 Preference of the next hop
4 Time when an IS-IS device enters the overload state
6.5.2 Configuring IPv4 IS-IS Route Leaking
Configuring IS-IS route leaking enables you to optimize IS-IS route selection on a two-level-
area network.
Context
If multiple Level-1-2 devices in a Level-1 area are connected to devices in the Level-2 area, a
Level-1 LSP sent by each Level-1-2 device carries an ATT flag bit of 1. This Level-1 area will
have multiple routes to the Level-2 area and to other Level-1 areas.
By default, routes in a Level-1 area can be leaked into the Level-2 area so that Level-1-2 and
Level-2 devices can learn about the topology of the entire network. Devices in a Level-1 area
are unaware of the entire network topology because they only maintain LSDBs in the local
Level-1 area. Therefore, a device in a Level-1 area can forward traffic to a Level-2 device only
through the nearest Level-1-2 device. The route used may not be the optimal route to the
destination.
To enable a device in a Level-1 area to select the optimal route, configure IPv4 IS-IS route
leaking so that specified routes in the Level-2 area can be leaked into the local Level-1 area.
Routes of services deployed only in the local Level-1 area do not need to be leaked into the
Level-2 area. A policy can be configured to leak only desired routes into the Level-2 area.
Procedure
l Specify routes in the Level-2 area and other Level-1 areas that can be leaked into the local
Level-1 area.
1. Run:
system-view
The system view is displayed.
2. Run:
isis [ process-id ]
The IS-IS view is displayed.
3. Run:
import-route isis level-2 into level-1 [ tag tag | filter-policy { acl-
number | acl-name acl-name | ip-prefix ip-prefix-name | route-policy route-
policy-name } ]
*
Routes in the Level-2 area and other Level-1 areas that meet the specified conditions
are leaked into the local Level-1 area.
S6700 Series Ethernet Switches
Configuration Guide - IP Routing 6 IS-IS Configuration
Issue 01 (2012-03-15) Huawei Proprietary and Confidential
Copyright © Huawei Technologies Co., Ltd.
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