Huawei Quidway NetEngine80E Configuration Manual page 678

HUAWEI NetEngine80E/40E Router
Configuration Guide - IP Routing
Networking Requirements
Figure 7-6
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Figure 7-6 Networking diagram for configuring IS-IS route summarization
Configuration Roadmap
The configuration roadmap is as follows:
1.
2.
3.
Data Preparation
To complete the configuration, you need the following data:
Issue 02 (2014-09-30)
shows a networking example.
Router A, Router B, and Router C are configured with IS-IS to communicate.
Router A belongs to area 20. Router B and Router C belong to area 10.
Router A is a Level-2 device. Router B is a Level-1-2 device. Router C is a Level-1 device.
Router B maintains both the Level-1 and Level-2 LSDBs. The routes to network segments
172.1.1.0/24, 172.1.2.0/24, and 172.1.3.0/24 in the Level-1 area can be leaked into the
Level-2 area. If the interface with the IP address 172.1.1.1/24 on Router C regularly
alternates between Up and Down states, LSPs in the Level-2 area will be frequently flooded
and Router A will often calculate routes using the SPF algorithm. This burdens the CPU
of Router A and may even cause route flapping on the network.
To solve this problem, configure Router B to summarize routes to the three network
segments into the route 172.1.0.0/16. This summarization reduces the number of routes to
be maintained by Router B and prevents interface-state alteration in the Level-1 area from
affecting router convergence in the Level-2 area.
Network1
GE2/0/0
172.1.1.0/24
172.1.1.1/24
GE3/0/0
172.1.2.1/24
Network2
172.1.2.0/24
GE4/0/0
172.1.3.1/24
Network3
172.1.3.0/24
Enable IS-IS on each router, configure the levels, and specify network entities.
Check the IS-IS routing table of Router A.
Configure Router B to summarize routes.
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RouterC
RouterB
L1
L1/L2
GE1/0/0
172.1.4.2/24
GE1/0/0
172.1.4.1/24
Area10
7 IS-IS Configuration
RouterA
L2
GE2/0/0
172.2.1.1/24
GE2/0/0
172.2.1.2/24
Area20
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