Example for Configuring IS-IS Route Leaking
Networking Requirements
As shown in Figure 7-34, IS-IS is configured on six routers. RouterA and RouterB are Level-1 routers, and RouterC and RouterD are Level-1-2 routers. They belong to area 10. RouterE and RouterF are Level-2 routers and belong to area 20. The cost of other interfaces except GE1/0/0 on RouterC (its cost is 40) is 10. Routes need to be leaked from Level-2 area to Level-1 area so that the router from RouterA to RouterF becomes the optimal route.
Configuration Roadmap
- Configure IP addresses for interfaces and enable IS-IS on each router so that the routers can be interconnected.
- Configure RouterA and RouterB are Level-1 routers, and RouterC and RouterD are Level-1-2 routers. They belong to area 10. RouterE and RouterF are Level-2 routers and belong to area 20.
- Configure the cost of other interfaces except GE1/0/0 on RouterC (its cost is 40) is 10.
- Configure routes to be leaked from Level-2 area to Level-1 area so that the router from RouterA to RouterF becomes the optimal route.
Procedure
- Configure IP addresses for interfaces on each router.
# Configure RouterA. The configurations of RouterB, RouterC, RouterD, RouterE and RouterF are similar to the configuration of RouterA, and are not mentioned here.
<Huawei> system-view [Huawei] sysname RouterA [RouterA] interface gigabitethernet 1/0/0 [RouterA-GigabitEthernet1/0/0] ip address 192.168.1.1 24 [RouterA-GigabitEthernet1/0/0] quit
- Configure basic IS-IS functions.
# Configure RouterA.
[RouterA] isis 10 [RouterA-isis-10] is-level level-1 [RouterA-isis-10] network-entity 10.0000.0000.0001.00 [RouterA-isis-10] quit [RouterA] interface gigabitethernet 1/0/0 [RouterA-GigabitEthernet1/0/0] isis enable 10 [RouterA-GigabitEthernet1/0/0] quit
# Configure RouterB.
[RouterB] isis 10 [RouterB-isis-10] is-level level-1 [RouterB-isis-10] network-entity 10.0000.0000.0002.00 [RouterB-isis-10] quit [RouterB] interface gigabitethernet 1/0/0 [RouterB-GigabitEthernet1/0/0] isis enable 10 [RouterB-GigabitEthernet1/0/0] quit
# Configure RouterC.
[RouterC] isis 10 [RouterC-isis-10] network-entity 10.0000.0000.0003.00 [RouterC-isis-10] quit [RouterC] interface gigabitethernet 1/0/0 [RouterC-GigabitEthernet1/0/0] isis enable 10 [RouterC-GigabitEthernet1/0/0] isis cost 40 level-2 [RouterC-GigabitEthernet1/0/0] quit
# Configure RouterD.
[RouterD] isis 10 [RouterD-isis-10] network-entity 10.0000.0000.0004.00 [RouterD-isis-10] quit [RouterD] interface gigabitethernet 1/0/0 [RouterD-GigabitEthernet1/0/0] isis enable 10 [RouterD-GigabitEthernet1/0/0] quit
# Configure RouterE.
[RouterE] isis 10 [RouterE-isis-10] is-level level-2 [RouterE-isis-10] network-entity 20.0000.0000.0005.00 [RouterE-isis-10] quit [RouterE] interface gigabitethernet 1/0/0 [RouterE-GigabitEthernet1/0/0] isis enable 10 [RouterE-GigabitEthernet1/0/0] quit
# Configure RouterF.
[RouterF] isis 10 [RouterF-isis-10] is-level level-2 [RouterF-isis-10] network-entity 20.0000.0000.0006.00 [RouterF-isis-10] quit [RouterF] interface gigabitethernet 1/0/0 [RouterF-GigabitEthernet1/0/0] isis enable 10 [RouterF-GigabitEthernet1/0/0] quit
The configurations of GigabitEthernet 2/0/0, and GigabitEthernet 3/0/0 are similar to the configuration of GigabitEthernet 1/0/0, and are not mentioned here.
- Configure route leaking on RouterD.
[RouterD] isis 10 [RouterD-isis-10] import-route isis level-2 into level-1 [RouterD-isis-10] quit
- Verify the configuration.
# Before configuring route leaking on RouterD, run the tracert 192.168.6.2 command on RouterA. The path from RouterA to RouterF is RouterA -> RouterC -> RouterE -> RouterF. The path cost is 60 (10+40+10).
# After configuring route leaking on RouterD, run the tracert 192.168.6.2 command on RouterA. The path from RouterA to RouterF is RouterA -> RouterB -> RouterD -> RouterE -> RouterF. The path cost is +10 (10+10+10+10). The route from RouterA to RouterF becomes the optimal route.
Configuration Files
Configuration file of RouterA
# sysname RouterA # isis 10 is-level level-1 network-entity 10.0000.0000.0001.00 # interface GigabitEthernet1/0/0 ip address 192.168.1.1 255.255.255.0 isis enable 10 # interface GigabitEthernet2/0/0 ip address 192.168.2.1 255.255.255.0 isis enable 10 #
Configuration file of RouterB
# sysname RouterB # isis 10 is-level level-1 network-entity 10.0000.0000.0002.00 # interface GigabitEthernet1/0/0 ip address 192.168.1.2 255.255.255.0 isis enable 10 # interface GigabitEthernet2/0/0 ip address 192.168.3.1 255.255.255.0 isis enable 10 #
Configuration file of RouterC
# sysname RouterC # isis 10 network-entity 10.0000.0000.0003.00 # interface GigabitEthernet1/0/0 ip address 192.168.4.1 255.255.255.0 isis enable 10 isis cost 40 level-2 # interface GigabitEthernet2/0/0 ip address 192.168.2.2 255.255.255.0 isis enable 10 #
Configuration file of RouterD
# sysname RouterD # isis 10 network-entity 10.0000.0000.0004.00 import-route isis level-2 into level-1 # interface GigabitEthernet1/0/0 ip address 192.168.3.2 255.255.255.0 isis enable 10 # interface GigabitEthernet2/0/0 ip address 192.168.5.1 255.255.255.0 isis enable 10 #
Configuration file of RouterE
# sysname RouterE # isis 10 is-level level-2 network-entity 20.0000.0000.0005.00 # interface GigabitEthernet1/0/0 ip address 192.168.4.2 255.255.255.0 isis enable 10 # interface GigabitEthernet2/0/0 ip address 192.168.5.2 255.255.255.0 isis enable 10 # interface GigabitEthernet3/0/0 ip address 192.168.6.1 255.255.255.0 isis enable 10 #
Configuration file of RouterF
# sysname RouterF # isis 10 is-level level-2 network-entity 20.0000.0000.0006.00 # interface GigabitEthernet1/0/0 ip address 192.168.6.2 255.255.255.0 isis enable 10 #
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