Configure IS-IS Routing Redistribution

Network Requirements

Configure the redistribution to introduce the external routing to the IS-IS, enabling network interconnection between devices.
Device1 and Device2 are the Level-2 routers. Configure the IS-IS and the Area 10. Configure the OSPF on Device2 and Device3. Redistribute the OSPF routing to the IS-IS through the configuration on Device2.

Network Topology

Networking of the IS-IS routing redistribution

Figure 9–4 Networking of the IS-IS routing redistribution

Configuration Steps

Step 1: Configure the IP address of the interfaces. (Omitted)

Step 2: Configure the IS-IS and enable the process on the interface.

#Configure the IS-IS process as 100, area number as 10, and type as Level-2 and enable the process on the interface on Device1.

Device1#configure terminal
Device1(config)#router isis 100
Device1(config-isis)#net 10.0000.0000.0001.00
Device1(config-isis)#is-type level-2
Device1(config-isis)#metric-style wide
Device1(config-isis)#exit
Device1(config)#interface vlan2
Device1(config-if-vlan2)#ip router isis 100
Device1(config-if-vlan2)#exit
Device1(config)#interface vlan3
Device1(config-if-vlan3)#ip router isis 100
Device1(config-if-vlan3)#exit

#Configure the IS-IS process as 100, area number as 10, and type as Level-1-2 and enable the process on the interface on Device2.

Device2#configure terminal
Device2(config)#router isis 100
Device2(config-isis)#net 10.0000.0000.0002.00
Device2(config-isis)#is-type level-2
Device2(config-isis)#metric-style wide
Device2(config-isis)#exit
Device2(config)#interface vlan3
Device2(config-if-vlan3)#ip router isis 100
Device2(config-if-vlan3)#exit

Step 3: Configure the OSPF.

#Configure Device2.

Device2(config)#router ospf 100
Device2(config-ospf)#network 200.1.1.0 0.0.0.255 area 0
Device2(config-ospf)#exit

#Configure Device3.

Device3#configure terminal
Device3(config)#router ospf 100
Device3(config-ospf)#network 210.1.1.0 0.0.0.255 area 0
Device3(config-ospf)#network 200.1.1.0 0.0.0.255 area 0
Device3(config-ospf)#exit

#View the routing table of Device1. Device1 does not learn the OSPF routing redistributed by Device2.

Device1#show ip route 
Codes: C - connected, S - static, R - RIP, O - OSPF, OE-OSPF External, M - Management 
       D - Redirect, E - IRMP, EX - IRMP external, o - SNSP, B - BGP, i-IS-IS  
 
Gateway of last resort is not set 
 
C 10.1.1.0/24 is directly connected, 00:58:39, vlan2 
C 100.1.1.0/24 is directly connected, 06:55:35, vlan3
C 127.0.0.0/8 is directly connected, 603:06:22, lo0 
 
Device1#show isis ipv4 route 
IS-IS Instance 100, VRF Kernel, IPv4 routes table (Counter 2):
L2 10.1.1.0/24, flags none, metric 10, from network connected 
     via 0.0.0.0, vlan2 
L2 100.1.1.0/24, flags none, metric 10, from network connected 
     via 0.0.0.0, vlan3 
 
Device1#show isis database detail  
IS-IS Instance 100 Level-2 Link State Database (Counter 3, LSP-MTU 1492): 
LSPID        LSP Seq Num LSP Checksum LSP Holdtime Length ATT/P/OL
0000.0000.0001.00-00* 0x00000046 0x489E       1123     71   0/0/0 
  NLPID:    IPv4 
  Area Address: 10 
  IP Address: 100.1.1.1 
  Metric: 10        IS-Extended 0000.0000.0001.01 
  Metric: 10        IP-Extended 10.1.1.0/24 
  Metric: 10        IP-Extended 100.1.1.0/24 
0000.0000.0001.01-00* 0x00000045 0x097D       1103     51   0/0/0 
  Metric: 0         IS-Extended 0000.0000.0001.00 
  Metric: 0         IS-Extended 0000.0000.0002.00 
0000.0000.0002.00-00 0x000000CB 0xEEA6       679      63   0/0/0 
  NLPID:    IPv4 
 
  Area Address: 10 
  IP Address	100.1.1.2 
  Metric: 10        IS-Extended 0000.0000.0001.01 
  Metric: 10        IP-Extended 100.1.1.0/24

#View the routing table of Device2. Device2 learns the IS-IS and OSPF routing.

Device2#show ip route 
Codes: C - connected, S - static, R - RIP, O - OSPF, OE-OSPF External, M Management 
       D - Redirect, E - IRMP, EX - IRMP external, o - SNSP, B BGP, i-IS-IS  
 
Gateway of last resort is not set 
 
i 10.1.1.0/24 [115/20] via 100.1.1.1, 15:45:37, vlan3
C 100.1.1.0/24 is directly connected, 22:38:58, vlan3
C 127.0.0.0/8 is directly connected, 300:03:03, lo0 
C 200.1.1.0/24 is directly connected, 22:38:58, vlan2
O 210.1.1.1/32 [110/2] via 200.1.1.2, 15:43:35, vlan2 
 
Device2#show isis ipv4 route 
IS-IS Instance 100, VRF Kernel, IPv4 routes table (Counter 2):
L2 10.1.1.0/24, flags none, metric 20, from learned, installed 
     via 100.1.1.1, vlan3, neighbor 0000.0000.0001 
L2 100.1.1.0/24, flags none, metric 10, from network connected 
     via 0.0.0.0, vlan3 
 
Device2#show isis database detail  
IS-IS Instance 100 Level-2 Link State Database (Counter 3, LSP-MTU 1492): 
LSPID        LSP Seq Num LSP Checksum LSP Holdtime Length ATT/P/OL
0000.0000.0001.00-00 0x00000046 0x489E       911      71   0/0/0 
  NLPID:    IPv4 
  Area Address: 10 
  IP Address: 100.1.1.1 
  Metric: 10        IS-Extended 0000.0000.0001.01 
  Metric: 10        IP-Extended 10.1.1.0/24 
  Metric: 10        IP-Extended 100.1.1.0/24 
0000.0000.0001.01-00 0x00000045 0x097D       892      51   0/0/0 
  Metric: 0         IS-Extended 0000.0000.0001.00 
  Metric: 0         IS-Extended 0000.0000.0002.00 
0000.0000.0002.00-00* 0x000000CB 0xEEA6       467      63   0/0/0 
  NLPID:    IPv4 
  Area Address: 10 
  IP Address: 100.1.1.2 
  Metric: 10        IS-Extended 0000.0000.0001.01 
  Metric: 10        IP-Extended 100.1.1.0/24

Step 4: Configure the IS-IS to redistribute the OSPF routing.

#Configure the OSPF routing to be redistributed to IS-IS Level-2 on Device2.

Device2(config)#router isis 100
Device2(config-isis)#address-family ipv4 unicast
Device2(config-isis-af)#redistribute ospf 100 level-2
Device2(config-isis-af)#exit Device2(config-isis)#exit

Step 5: Check the result.

#View the routing information of Device1. Device1 leans the OSPF routing redistributed by Device2.

Device1#show ip route 
Codes: C - connected, S - static, R - RIP, O - OSPF, OE-OSPF External, M - Management 
       D - Redirect, E - IRMP, EX - IRMP external, o - SNSP, B - BGP, i-IS-IS  
 
Gateway of last resort is not set 
 
C 10.1.1.0/24 is directly connected, 16:47:30, vlan2 
C 100.1.1.0/24 is directly connected, 22:44:27, vlan3
C 127.0.0.0/8 is directly connected, 618:55:13, lo0 
i 200.1.1.0/24 [115/10] via 100.1.1.2, 00:00:05, vlan3
i 210.1.1.1/32 [115/10] via 100.1.1.2, 00:00:05, vlan3 
 
Device1#show isis ipv4 route 
IS-IS Instance 100, VRF Kernel, IPv4 routes table (Counter 4):
L2 10.1.1.0/24, flags none, metric 10, from network connected 
     via 0.0.0.0, vlan2 
L2 100.1.1.0/24, flags none, metric 10, from network connected 
     via 0.0.0.0, vlan3 
L2 200.1.1.0/24, flags none, metric 10, from learned, installed 
     via 100.1.1.2, vlan3, neighbor 0000.0000.0002 
L2 210.1.1.1/32, flags none, metric 10, from learned, installed 
     via 100.1.1.2, vlan3, neighbor 0000.0000.0002 
 
Device1#show isis database detail  
IS-IS Instance 100 Level-2 Link State Database (Counter 3, LSP-MTU 1492): 
LSPID        LSP Seq Num LSP Checksum LSP Holdtime Length ATT/P/OL
0000.0000.0001.00-00* 0x00000046 0x489E       626      71   0/0/0 
  NLPID:    IPv4 
  Area Address: 10 
  IP Address: 100.1.1.1 
  Metric: 10        IS-Extended 0000.0000.0001.01 
  Metric: 10        IP-Extended 10.1.1.0/24 
  Metric: 10        IP-Extended 100.1.1.0/24 
0000.0000.0001.01-00* 0x00000045 0x097D       606      51   0/0/0 
  Metric: 0         IS-Extended 0000.0000.0001.00 
  Metric: 0         IS-Extended 0000.0000.0002.00 
0000.0000.0002.00-00 0x000000CD 0xC6E2       1184     80   0/0/0 
  NLPID:    IPv4 
  Area Address: 10 
  IP Address: 100.1.1.2 
  Metric: 10        IS-Extended 0000.0000.0001.01 
  Metric: 10        IP-Extended 100.1.1.0/24 
  Metric: 0         IP-Extended 200.1.1.0/24 
  Metric: 0         IP-Extended 210.1.1.1/32

Device1 learns the redistributed OSPF routing.