Configuration Example of Interaction Between IS-IS and BGP
- Tracy Yang
Analytics
Networking Requirements
Figure 1. Configuration Example of Interaction Between IS-IS and BGP
As shown in Figure 1, there are three switches (Switch A, Switch B and Switch C) in this sample network. IS-IS routing protocol runs between Switch A and Switch B, and EBGP routing protocol runs between Switch B and Switch C. To enable communication between Switch A and Switch C, you need to configure to redistribute IS-IS routes to BGP routes, and BGP routes to IS-IS routes on Switch B.
Follow the configuration roadmap below to complete the configuration:
Configure VLAN interface and IP address for each interface to make the network reachable.
Enable IS-IS on Switch A and Switch B, and enable EBGP on Switch B and Switch C.
On Switch B, configure route redistribution between route protocol IS-IS and BGP.
Procedure
Switch A
Step1 Configure VLAN interface.
admin@SwitchA# set vlans vlan-id 100 l3-interface vlan100
admin@SwitchA# set vlans vlan-id 1000 l3-interface vlan1000
admin@SwitchA# set interface gigabit-ethernet te-1/1/3 family ethernet-switching native-vlan-id 100
admin@SwitchA# set interface gigabit-ethernet te-1/1/1 family ethernet-switching native-vlan-id 1000
admin@SwitchA# set l3-interface vlan-interface vlan100 address 192.168.20.1 prefix-length 24
admin@SwitchA# set l3-interface vlan-interface vlan1000 address 192.168.1.6 prefix-length 24Step2 Enable IS-IS for the network segment.
admin@SwitchA# set protocols isis area-tag instance1 network-entity 32.0001.0040.0220.0001.00
admin@SwitchA# set protocols isis area-tag instance1 interface vlan100 ipv4-routing
admin@SwitchA# set protocols isis area-tag instance1 interface vlan1000 ipv4-routingStep3 Enable IP routing.
admin@SwitchA# set ip routing enable trueStep4 Commit the configuration.
Switch B
Step1 Configure VLAN interface.
Step2 Enable IS-IS for the specified network segment.
Step3 Configure EBGP connection between Switch B and Switch C.
Step4 Enable IP routing.
Step5 Commit the configuration.
Switch C
Step1 Configure VLAN interface.
Step2 Configure EBGP connection between Switch B and Switch C.
Step3 Enable IP routing.
Step4 Commit the configuration.
View IS-IS Route Table on Switch A
On Switch A, use command run show isis route to check IS-IS route table, the route 55.55.55.0/24 does not exist.
Configuring Switch B to Import Route between BGP and IS-IS
View IS-IS Route Table on Switch A
On Switch A, use command run show isis route to view IS-IS route table again, route 55.55.55.0/24 has been inserted to Switch A’s routing table with metric value 10. Switch A and Switch C can communicate with each other now.
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