Network Kings

Redistribution between OSPF and EIGRP  

route redistribution between ospf and eigrp

In a network, there is a possibility that it is running on both OSPF and EIGRP and the route of OSPF cannot be advertised to EIGRP by itself. Similarly, routes of EIGRP cannot be advertised to OSPF by itself.   

We can make use of Redistribution to advertise routes between each other. 

Route Redistribution is a process that helps to exchange routing information from one routing protocol to another. It allows routes from one routing protocol to be advertised into another. 

Let us see how we can redistribute routes between OSPF and EIGRP with the help of this basic topology. 

Redistribution between OSPF and EIGRP

Redistribution between OSPF and EIGRP

R1: –  

R1(config)#interface GigabitEthernet0/0/0  

R1(config-if)#ip address 192.168.12.1 255.255.255.0  

R1(config-if)#no shutdown   

R1(config)#interface loopback 1  

R1(config-if)#ip address 1.1.1.1 255.255.255.0  

R1(config-if)#exit   

R1(config)#router ospf 1  

R1(config-router)#network 192.168.12.0 0.0.0.255 area 0  

R1(config-router)#network 1.1.1.0 0.0.0.255 area 0   

R2: –   

R2(config)#interface GigabitEthernet0/0/1  

R2(config-if)#exit  

R2(config)#interface GigabitEthernet0/0/0  

R2(config-if)#ip address 192.168.23.2 255.255.255.0  

R2(config-if)#no shutdown   

R2(config)#interface loopback 1  

R2(config-if)#ip address 2.2.2.1 255.255.255.0   

R2(config)#router eigrp 1  

R2(config-router)#no auto-summary   

R2(config-router)#network 192.168.23.0  

R2(config-router)#network 2.2.2.0  

R2(config-router)#exit  

R2(config)#exit   

R3:-    

R3(config)#interface GigabitEthernet0/0/0  

R3(config-if)#ip address 192.168.12.2 255.255.255.0  

R3(config-if)#no shutdown   

R3(config-if)#exit  

R3(config)#interface GigabitEthernet0/0/1  

R3(config-if)#ip address 192.168.23.3 255.255.255.0  

R3(config-if)#no shutdown    

R3(config)#router ospf 1  

R3(config-router)#network 192.168.12.0 0.0.0.255 area 0  

R3(config-router)#exit   

R3(config)#router eigrp 1  

R3(config-router)#no auto-summary   

R3(config-router)#network 192.168.23.0   

R3(config-router)#exit    

Let us see the table before redistribution.   

R1#show ip route   

Codes:  

L – local, C – connected, S – static, R – RIP, M – mobile, B – BGP  

D – EIGRP, EX – EIGRP external, O – OSPF, IA – OSPF inter area  

N1 – OSPF NSSA external type 1, N2 – OSPF NSSA external type 2  

E1 – OSPF external type 1, E2 – OSPF external type 2, E – EGP  

i – IS-IS, L1 – IS-IS level-1, L2 – IS-IS level-2, ia – IS-IS inter area  

* – candidate default, U – per-user static route, o – ODR  

P – periodic downloaded static route   

Gateway of last resort is not set   

1.0.0.0/8 is variably subnetted, 2 subnets, 2 masks  

C 1.1.1.0/24 is directly connected, Loopback1  

L 1.1.1.1/32 is directly connected, Loopback1  

192.168.12.0/24 is variably subnetted, 2 subnets, 2 masks  

C 192.168.12.0/24 is directly connected, GigabitEthernet0/0/0  

L 192.168.12.1/32 is directly connected, GigabitEthernet0/0/0   

R2#show ip route   

Codes:   

L – local, C – connected, S – static, R – RIP, M – mobile, B – BGP  

 D – EIGRP, EX – EIGRP external, O – OSPF, IA – OSPF inter area  

 N1 – OSPF NSSA external type 1, N2 – OSPF NSSA external type 2  

 E1 – OSPF external type 1, E2 – OSPF external type 2, E – EGP  

 i – IS-IS, L1 – IS-IS level-1, L2 – IS-IS level-2, ia – IS-IS inter area  

 * – candidate default, U – per-user static route, o – ODR  

 P – periodic downloaded static route   

Gateway of last resort is not set   

2.0.0.0/8 is variably subnetted, 2 subnets, 2 masks  

C 2.2.2.0/24 is directly connected, Loopback1  

L 2.2.2.1/32 is directly connected, Loopback1  

192.168.23.0/24 is variably subnetted, 2 subnets, 2 masks  

C 192.168.23.0/24 is directly connected, GigabitEthernet0/0/0  

L 192.168.23.2/32 is directly connected, GigabitEthernet0/0/0   

R3#show ip route   

Codes:  

L – local, C – connected, S – static, R – RIP, M – mobile, B – BGP  

D – EIGRP, EX – EIGRP external, O – OSPF, IA – OSPF inter area  

N1 – OSPF NSSA external type 1, N2 – OSPF NSSA external type 2  

E1 – OSPF external type 1, E2 – OSPF external type 2, E – EGP  

i – IS-IS, L1 – IS-IS level-1, L2 – IS-IS level-2, ia – IS-IS inter area  

* – candidate default, U – per-user static route, o – ODR  

P – periodic downloaded static route   

Gateway of last resort is not set    

1.0.0.0/32 is subnetted, 1 subnets  

O 1.1.1.1/32 [110/2] via 192.168.12.1, 00:02:27, GigabitEthernet0/0/0  

2.0.0.0/24 is subnetted, 1 subnets  

D 2.2.2.0/24 [90/130816] via 192.168.23.2, 00:00:37, GigabitEthernet0/0/1  

192.168.12.0/24 is variably subnetted, 2 subnets, 2 masks  

C 192.168.12.0/24 is directly connected, GigabitEthernet0/0/0  

L 192.168.12.2/32 is directly connected, GigabitEthernet0/0/0  

192.168.23.0/24 is variably subnetted, 2 subnets, 2 masks  

C 192.168.23.0/24 is directly connected, GigabitEthernet0/0/1  

L 192.168.23.3/32 is directly connected, GigabitEthernet0/0/1  

Redistribution: -

R3#configure t  

R3(config)#router eigrp 1  

R3(config-router)#redistribute ospf ?  

<1-65535> Process ID   

R3(config-router)#redistribute ospf 1 ?   

match Redistribution of OSPF routes  

metric Metric for redistributed routes  

<cr>   

R3(config-router)#redistribute ospf 1 metric ?   

<1-4294967295> Bandwidth metric in Kbits per second   

R3(config-router)#redistribute ospf 1 metric 1000 ?   

<0-4294967295> EIGRP delay metric, in 10 microsecond units   

R3(config-router)#redistribute ospf 1 metric 1000 100 ?   

<0-255> EIGRP reliability metric where 255 is 100% reliable   

R3(config-router)#redistribute ospf 1 metric 1000 100 255 ?   

<1-255> EIGRP Effective bandwidth metric (Loading) where 255 is 100% loaded   

R3(config-router)#redistribute ospf 1 metric 1000 100 255 ?   

<1-255> EIGRP Effective bandwidth metric (Loading) where 255 is 100% loaded   

R3(config-router)#redistribute ospf 1 metric 1000 100 255 1 ?   

<1-65535> EIGRP MTU of the path   

R3(config-router)#redistribute ospf 1 metric 1000 100 255 1 1500  

R3(config-router)#exit   

R3(config)#router ospf 1   

R3(config-router)#redistribute eigrp ?   

<1-65535> Autonomous system number   

R3(config-router)#redistribute eigrp 1   

% Only classful networks will be redistributed   

R3(config-router)#redistribute eigrp 1 ?   

metric Metric for redistributed routes  

metric-type OSPF/IS-IS exterior metric type for redistributed routes  

subnets Consider subnets for redistribution into OSPF  

tag Set tag for routes redistributed into OSPF  

<cr>   

R3(config-router)#redistribute eigrp 1 subnets ?   

tag Set tag for routes redistributed into OSPF  

<cr>   

R3(config-router)#redistribute eigrp 1 subnets 

Verification: -

R1>show ip route   

Codes:  

L – local, C – connected, S – static, R – RIP, M – mobile, B – BGP  

D – EIGRP, EX – EIGRP external, O – OSPF, IA – OSPF inter area  

N1 – OSPF NSSA external type 1, N2 – OSPF NSSA external type 2  

E1 – OSPF external type 1, E2 – OSPF external type 2, E – EGP  

i – IS-IS, L1 – IS-IS level-1, L2 – IS-IS level-2, ia – IS-IS inter area  

* – candidate default, U – per-user static route, o – ODR  

P – periodic downloaded static route  

Gateway of last resort is not set

 1.0.0.0/8 is variably subnetted, 2 subnets, 2 masks  

C 1.1.1.0/24 is directly connected, Loopback1  

L 1.1.1.1/32 is directly connected, Loopback1  

 2.0.0.0/24 is subnetted, 1 subnets  

O E2 2.2.2.0/24 [110/20] via 192.168.12.2, 00:00:27, GigabitEthernet0/0/0  

192.168.12.0/24 is variably subnetted, 2 subnets, 2 masks  

C 192.168.12.0/24 is directly connected, GigabitEthernet0/0/0  

L 192.168.12.1/32 is directly connected, GigabitEthernet0/0/0  

O E2 192.168.23.0/24 [110/20] via 192.168.12.2, 00:00:46, GigabitEthernet0/0/0  

R2#show ip route   

Codes:  

L – local, C – connected, S – static, R – RIP, M – mobile, B – BGP  

D – EIGRP, EX – EIGRP external, O – OSPF, IA – OSPF inter area  

N1 – OSPF NSSA external type 1, N2 – OSPF NSSA external type 2  

E1 – OSPF external type 1, E2 – OSPF external type 2, E – EGP  

i – IS-IS, L1 – IS-IS level-1, L2 – IS-IS level-2, ia – IS-IS inter area  

* – candidate default, U – per-user static route, o – ODR  

P – periodic downloaded static route  

Gateway of last resort is not set  

 1.0.0.0/32 is subnetted, 1 subnets  

D EX 1.1.1.1/32 [170/2585856] via 192.168.23.3, 00:01:40, GigabitEthernet0/0/0  

 2.0.0.0/8 is variably subnetted, 2 subnets, 2 masks  

C 2.2.2.0/24 is directly connected, Loopback1  

L 2.2.2.1/32 is directly connected, Loopback1  

D EX 192.168.12.0/24 [170/2585856] via 192.168.23.3, 00:01:40, GigabitEthernet0/0/0  

192.168.23.0/24 is variably subnetted, 2 subnets, 2 masks  

C 192.168.23.0/24 is directly connected, GigabitEthernet0/0/0  

L 192.168.23.2/32 is directly connected, GigabitEthernet0/0/0  

R3#show ip route   

Codes:  

L – local, C – connected, S – static, R – RIP, M – mobile, B BGP  

D – EIGRP, EX – EIGRP external, O – OSPF, IA – OSPF inter area  

N1 – OSPF NSSA external type 1, N2 – OSPF NSSA external type 2  

E1 – OSPF external type 1, E2 – OSPF external type 2, E – EGP  

i – IS-IS, L1 – IS-IS level-1, L2 – IS-IS level-2, ia – IS-IS inter area  

* – candidate default, U – per-user static route, o – ODR  

P – periodic downloaded static route  

Gateway of last resort is not set  

1.0.0.0/32 is subnetted, 1 subnets  

O 1.1.1.1/32 [110/2] via 192.168.12.1, 00:12:55, GigabitEthernet0/0/0  

2.0.0.0/24 is subnetted, 1 subnets  

D 2.2.2.0/24 [90/130816] via 192.168.23.2, 00:11:05, GigabitEthernet0/0/1  

192.168.12.0/24 is variably subnetted, 2 subnets, 2 masks  

C 192.168.12.0/24 is directly connected, GigabitEthernet0/0/0  

L 192.168.12.2/32 is directly connected, GigabitEthernet0/0/0  

192.168.23.0/24 is variably subnetted, 2 subnets, 2 masks  

C 192.168.23.0/24 is directly connected, GigabitEthernet0/0/1  

L 192.168.23.3/32 is directly connected, GigabitEthernet0/0/1