< Home

Example for Applying a Routing Policy for Importing Routes

Networking Requirements

In Figure 1, SwitchB exchanges routing information with SwitchA through OSPF, and with SwitchC through IS-IS. A user wants SwitchB to import IS-IS routes into the OSPF network. The user also wants the route to 172.17.1.0/24 on the OSPF network to have a low preference and the route to 172.17.2.0/24 to have a tag, making it easy to reference by a routing policy.

Figure 1 Networking diagram for applying a routing policy for importing routes

Device

Interface

VLANIF Interface

IP Address

SwitchA

GE0/0/1

VLANIF10

192.168.1.1/24

SwitchB

GE0/0/1

VLANIF10

192.168.1.2/24

SwitchB

GE0/0/2

VLANIF20

192.168.2.2/24

SwitchC

GE0/0/1

VLANIF20

192.168.2.1/24

SwitchC

GE0/0/2

VLANIF30

172.17.1.1/24

SwitchC

GE0/0/3

VLANIF40

172.17.2.1/24

SwitchC

GE0/0/4

VLANIF50

172.17.3.1/24

Configuration Roadmap

The configuration roadmap is as follows:

  1. Configure a routing policy on SwitchB, set the cost of the route to 172.17.1.0/24 to 100, and apply the routing policy when OSPF imports IS-IS routes. The routing policy allows the route to 172.17.1.0/24 to have a low preference.

  2. Configure a routing policy on SwitchB, set the tag of the route to 172.17.2.0/24 to 20, and apply the routing policy when OSPF imports IS-IS routes. This allows the tag of the route to 172.17.2.0/24 to take effect, making it easy to reference by a routing policy.

Procedure

  1. Add interfaces to VLANs.

    # Configure SwitchA. Ensure that the configurations of SwitchB, and SwitchC are the same as the configuration of SwitchA.

    <HUAWEI> system-view
[HUAWEI] sysname SwitchA
[SwitchA] vlan batch 10
[SwitchA] interface gigabitethernet 0/0/1
[SwitchA-GigabitEthernet0/0/1] port link-type trunk
[SwitchA-GigabitEthernet0/0/1] port trunk allow-pass vlan 10
[SwitchA-GigabitEthernet0/0/1] quit

  2. Assign IP addresses to VLANIF interfaces.

    # Configure SwitchA. Ensure that the configurations of SwitchB, and SwitchC are the same as the configuration of SwitchA.

    [SwitchA] interface vlanif 10
[SwitchA-Vlanif10] ip address 192.168.1.1 24
[SwitchA-Vlanif10] quit

  3. Configure IS-IS.

    # Configure SwitchC.

    [SwitchC] isis
[SwitchC-isis-1] is-level level-2
[SwitchC-isis-1] network-entity 10.0000.0000.0001.00
[SwitchC-isis-1] quit
[SwitchC] interface vlanif 20
[SwitchC-Vlanif20] isis enable
[SwitchC-Vlanif20] quit
[SwitchC] interface vlanif 30
[SwitchC-Vlanif30] isis enable
[SwitchC-Vlanif30] quit
[SwitchC] interface vlanif 40
[SwitchC-Vlanif40] isis enable
[SwitchC-Vlanif40] quit
[SwitchC] interface vlanif 50
[SwitchC-Vlanif50] isis enable
[SwitchC-Vlanif50] quit

    # Configure SwitchB.

    [SwitchB] isis
[SwitchB-isis-1] is-level level-2
[SwitchB-isis-1] network-entity 10.0000.0000.0002.00
[SwitchB-isis-1] quit
[SwitchB] interface vlanif 20
[SwitchB-Vlanif20] isis enable
[SwitchB-Vlanif20] quit

  4. Configure OSPF and import routes.

    # Configure SwitchA and enable OSPF.

    [SwitchA] ospf
[SwitchA-ospf-1] area 0
[SwitchA-ospf-1-area-0.0.0.0] network 192.168.1.0 0.0.0.255
[SwitchA-ospf-1-area-0.0.0.0] quit
[SwitchA-ospf-1] quit

    # Configure SwitchB, enable OSPF, and import IS-IS routes.

    [SwitchB] ospf
[SwitchB-ospf-1] area 0
[SwitchB-ospf-1-area-0.0.0.0] network 192.168.1.0 0.0.0.255
[SwitchB-ospf-1-area-0.0.0.0] quit
[SwitchB-ospf-1] import-route isis 1
[SwitchB-ospf-1] quit

    # Check the OSPF routing table on SwitchA. You can see the imported routes.

    [SwitchA] display ospf routing
 
          OSPF Process 1 with Router ID 192.168.1.1
                   Routing Tables
 
 Routing for Network
 Destination        Cost  Type       NextHop         AdvRouter       Area
 192.168.1.0/24     1     Transit    192.168.1.1     192.168.1.1     0.0.0.0
 
 Routing for ASEs
 Destination        Cost      Type       Tag         NextHop         AdvRouter
 172.17.1.0/24      1         Type2      1           192.168.1.2     192.168.1.2
 172.17.2.0/24      1         Type2      1           192.168.1.2     192.168.1.2
 172.17.3.0/24      1         Type2      1           192.168.1.2     192.168.1.2
 192.168.2.0/24     1         Type2      1           192.168.1.2     192.168.1.2
 
 Total Nets: 5
 Intra Area: 1  Inter Area: 0  ASE: 4  NSSA: 0

  5. Set the filtering list.

    # Configure ACL 2002 to match 172.17.2.0/24.

    [SwitchB] acl number 2002
[SwitchB-acl-basic-2002] rule permit source 172.17.2.0 0.0.0.255
[SwitchB-acl-basic-2002] quit

    # Configure an IP prefix list named prefix-a to match 172.17.1.0/24.

    [SwitchB] ip ip-prefix prefix-a index 10 permit 172.17.1.0 24

  6. Configure a routing policy. 

    [SwitchB] route-policy isis2ospf permit node 10
[SwitchB-route-policy] if-match ip-prefix prefix-a
[SwitchB-route-policy] apply cost 100
[SwitchB-route-policy] quit
[SwitchB] route-policy isis2ospf permit node 20
[SwitchB-route-policy] if-match acl 2002
[SwitchB-route-policy] apply tag 20
[SwitchB-route-policy] quit
[SwitchB] route-policy isis2ospf permit node 30  
[SwitchB-route-policy] quit

  7. Apply the routing policy when routes are imported.

    # Configure SwitchB and apply the routing policy when routes are imported.

    [SwitchB] ospf
[SwitchB-ospf-1] import-route isis 1 route-policy isis2ospf
[SwitchB-ospf-1] quit

    # Check the OSPF routing table on SwitchA. You can see that the cost of the route to 172.17.1.0/24 is 100; the tag of the route to 172.17.2.0/24 is 20; other route attributes remain unchanged.

    [SwitchA] display ospf routing
 
          OSPF Process 1 with Router ID 192.168.1.1
                   Routing Tables

 Routing for Network
 Destination        Cost  Type       NextHop         AdvRouter       Area
 192.168.1.0/24     1     Transit    192.168.1.1     192.168.1.1     0.0.0.0
 
 Routing for ASEs
 Destination        Cost      Type       Tag         NextHop           AdvRouter
 172.17.1.0/24      100       Type2      1           192.168.1.2       192.168.1.2
 172.17.2.0/24      1         Type2      20          192.168.1.2       192.168.1.2
 172.17.3.0/24      1         Type2      1           192.168.1.2       192.168.1.2
 192.168.2.0/24     1         Type2      1           192.168.1.2       192.168.1.2
  
 Total Nets: 5
 Intra Area: 1  Inter Area: 0  ASE: 4  NSSA: 0

Configuration Files

  • Configuration file of SwitchA

    #
sysname SwitchA
#
vlan batch 10
#
interface Vlanif10
 ip address 192.168.1.1 255.255.255.0
#
interface GigabitEthernet0/0/1
 port link-type trunk
 port trunk allow-pass vlan 10
#
ospf 1
 area 0.0.0.0
  network 192.168.1.0 0.0.0.255
#
return

  • Configuration file of SwitchB

    #
sysname SwitchB
#
vlan batch 10 20
#
acl number 2002
 rule 5 permit source 172.17.2.0 0.0.0.255
#
isis 1
 is-level level-2
 network-entity 10.0000.0000.0002.00
#
interface Vlanif10
 ip address 192.168.1.2 255.255.255.0
#
interface Vlanif20
 ip address 192.168.2.2 255.255.255.0
 isis enable 1
#
interface GigabitEthernet0/0/1
 port link-type trunk
 port trunk allow-pass vlan 10
#
interface GigabitEthernet0/0/2
 port link-type trunk
 port trunk allow-pass vlan 20
#
ospf 1
 import-route isis 1 route-policy isis2ospf
 area 0.0.0.0
  network 192.168.1.0 0.0.0.255
#
route-policy isis2ospf permit node 10
 if-match ip-prefix prefix-a
 apply cost 100
#
route-policy isis2ospf permit node 20
 if-match acl 2002
 apply tag 20
#
route-policy isis2ospf permit node 30
#
ip ip-prefix prefix-a index 10 permit 172.17.1.0 24
#
return

  • Configuration file of SwitchC

    #
sysname SwitchC
#
vlan batch 20 30 40 50
#
isis 1
 is-level level-2
 network-entity 10.0000.0000.0001.00
#
interface Vlanif20
 ip address 192.168.2.1 255.255.255.0
 isis enable 1
#
interface Vlanif30
 ip address 172.17.1.1 255.255.255.0
 isis enable 1
#
interface Vlanif40
 ip address 172.17.2.1 255.255.255.0
 isis enable 1
#
interface Vlanif50
 ip address 172.17.3.1 255.255.255.0
 isis enable 1
#
interface GigabitEthernet0/0/1
 port link-type trunk
 port trunk allow-pass vlan 20
#
interface GigabitEthernet0/0/2
 port link-type trunk
 port trunk allow-pass vlan 30
#
interface GigabitEthernet0/0/3
 port link-type trunk
 port trunk allow-pass vlan 40
#
interface GigabitEthernet0/0/4
 port link-type trunk
 port trunk allow-pass vlan 50
#
return
Parent Topic: Configuration Examples for Routing Policies
Copyright © Huawei Technologies Co., Ltd.
Copyright © Huawei Technologies Co., Ltd.
< Previous topic