IS-IS and OSPF Redistribution (Configuration Example on Nexus 9K)
Topology
OSPF and ISIS Initial Configuration
NX01:
NX01# show run int ethernet 1/1
version 9.3(9) Bios:version
interface Ethernet1/1
no switchport
ip address 172.31.10.1/30
ip router isis 10
no shutdown
NX01# show run int lo1
interface loopback1
ip address 10.1.1.1/32
ip router isis 10
NX01# show run | sec isis
router isis 10
net 11.1111.1111.1111.1111.00
is-type level-1
address-family ipv4 unicast
NX02:
NX02# show run int ethernet 1/1-2
version 9.3(9) Bios:version
interface Ethernet1/1
no switchport
ip address 172.31.10.2/30
ip router isis 10
no shutdown
interface Ethernet1/2
no switchport
ip address 192.168.20.1/30
ip ospf authentication message-digest
ip ospf authentication key-chain learnduty
ip router ospf 10 area 0.0.0.0
no shutdown
key chain learnduty
key 1
key-string cisco
feature ospf
router ospf 10
router-id 1.1.1.1
area 0.0.0.0 authentication message-digest
router isis 10
net 11.1111.2222.2222.2222.00
is-type level-1
address-family ipv4 unicast
NX03:
interface Ethernet1/2
no switchport
ip address 192.168.20.2/30
ip ospf authentication message-digest
ip ospf authentication key-chain learnduty
ip router ospf 10 area 0.0.0.0
no shutdown
interface loopback1
ip address 10.2.2.2/32
ip router ospf 10 area 0.0.0.0
key chain learnduty
key 1
key-string cisco
feature ospf
router ospf 10
router-id 2.2.2.2
OSPF and ISIS Redistribution
- Redistribute IS-IS into OSPF:
router ospf 10
redistribute isis 10 route-map 20
route-map 20 permit 10
match ip address prefix-list 20
ip prefix-list 20 seq 15 permit 10.1.1.1/32- Redistribute OSPF into IS-IS:
router isis 10
address-family ipv4 unicast
redistribute ospf 10 route-map 30
route-map 30 permit 10
match ip address prefix-list 30
ip prefix-list 30 seq 5 permit 10.2.2.2/32Verifications
On NX01, we can see that 10.2.2.2/32 was redistributed from OSPF to IS-IS:
NX01# show ip route
IP Route Table for VRF "default"
'*' denotes best ucast next-hop
'**' denotes best mcast next-hop
'[x/y]' denotes [preference/metric]
'%<string>' in via output denotes VRF <string>
10.1.1.1/32, ubest/mbest: 2/0, attached
*via 10.1.1.1, Lo1, [0/0], 02:05:45, local
*via 10.1.1.1, Lo1, [0/0], 02:05:45, direct
10.2.2.2/32, ubest/mbest: 1/0
*via 172.31.10.2, Eth1/1, [115/50], 00:00:17, isis-10, L1
172.31.10.0/30, ubest/mbest: 1/0, attached
*via 172.31.10.1, Eth1/1, [0/0], 01:41:01, direct
172.31.10.1/32, ubest/mbest: 1/0, attached
*via 172.31.10.1, Eth1/1, [0/0], 01:41:01, localMutually, on NX03, we see that 10.1.1.1/32 was redistributed from IS-IS to OSPF (by default as E2):
NX03# show ip route
IP Route Table for VRF "default"
'*' denotes best ucast next-hop
'**' denotes best mcast next-hop
'[x/y]' denotes [preference/metric]
'%<string>' in via output denotes VRF <string>
10.1.1.1/32, ubest/mbest: 1/0
*via 192.168.20.1, Eth1/2, [110/20], 01:39:49, ospf-10, type-2
10.2.2.2/32, ubest/mbest: 2/0, attached
*via 10.2.2.2, Lo1, [0/0], 00:10:11, local
*via 10.2.2.2, Lo1, [0/0], 00:10:11, direct
192.168.20.0/30, ubest/mbest: 1/0, attached
*via 192.168.20.2, Eth1/2, [0/0], 01:40:02, direct
192.168.20.2/32, ubest/mbest: 1/0, attached
*via 192.168.20.2, Eth1/2, [0/0], 01:40:02, local