ODR is not a routing protocol but an enhancement to CDP as it can propogate prefixes and only add 5 bytes into CDP. ODR must only be enabled on stub router. ODR will not work if other routing protocols are running. CDP should be running on all routers. We need to run ODR on hub router and all other spokes send their connected interfaces information to Hub via ODR (CDP update). Please note that we cannot redistribute static or dynamic routes to ODR but can redistribute ODR routes to dunamic protocols.
You can also load balance via ODR if you have multiple Hubs.
You can also load balance via ODR if you have multiple Hubs.
Requirement:
- In this topology R3 is a spoke and R2 is a Hub. We will running EIGRP between R1 and R2.
- R3 should send its loop-back (connected interfaces) information to the whole network without using static routing or dynamic routing protocols.
- R3 should learn EIGRP routes
| ! R1 Configuration interface FastEthernet0/0 ip address 1.1.1.1 255.0.0.0 no shut router eigrp 10 network 1.0.0.0 ! R2 Configuration router odr interface FastEthernet0/0 ip address 1.1.1.2 255.0.0.0 no shutdown interface Serial0/0 ip address 2.2.2.1 255.0.0.0 no shutdown router eigrp 10 network 1.0.0.0 redistribute odr metric 10 10 10 10 10 ! R3 Configuration interface Loopback0 ip address 40.1.1.1 255.255.255.255 interface Loopback1 ip address 40.1.1.2 255.255.255.255 interface Serial0/0 ip address 2.2.2.2 255.0.0.0 no shutdown | Configuration Explanation This command is letting R2 to send itself as a default route to all spoke routers i.e. R1 and will get connected information update from neighbors CDP update Redistributing ODR routes to EIGRP Connected loopback interface Connected loopback interface |
Verification
R3#show ip route odr
o* 0.0.0.0/0 [160/1] via 2.2.2.1, 00:00:45, Serial0/0
R3#show ip route
Gateway of last resort is 2.2.2.1 to network 0.0.0.0
C 2.0.0.0/8 is directly connected, Serial0/0
40.0.0.0/32 is subnetted, 2 subnets
C 40.1.1.1 is directly connected, Loopback0
C 40.1.1.2 is directly connected, Loopback1
o* 0.0.0.0/0 [160/1] via 2.2.2.1, 00:00:13, Serial0/0
This output shows that by configuring R2 as ODR; R1 (spoke) gets default route toward hub (R2)
R2#show ip route
C 1.0.0.0/8 is directly connected, FastEthernet0/0
C 2.0.0.0/8 is directly connected, Serial0/0
40.0.0.0/32 is subnetted, 2 subnets
o 40.1.1.1 [160/1] via 2.2.2.2, 00:00:30, Serial0/0
o 40.1.1.2 [160/1] via 2.2.2.2, 00:00:30, Serial0/0
R2 has learnt both ODR routes from CDP update
R1#show ip route
C 1.0.0.0/8 is directly connected, FastEthernet0/0
40.0.0.0/32 is subnetted, 2 subnets
D EX 40.1.1.1 [170/256028160] via 1.1.1.2, 00:00:37, FastEthernet0/0
D EX 40.1.1.2 [170/256028160] via 1.1.1.2, 00:00:37, FastEthernet0/0
Redistributed ODR routes to EIGRP
o* 0.0.0.0/0 [160/1] via 2.2.2.1, 00:00:45, Serial0/0
R3#show ip route
Gateway of last resort is 2.2.2.1 to network 0.0.0.0
C 2.0.0.0/8 is directly connected, Serial0/0
40.0.0.0/32 is subnetted, 2 subnets
C 40.1.1.1 is directly connected, Loopback0
C 40.1.1.2 is directly connected, Loopback1
o* 0.0.0.0/0 [160/1] via 2.2.2.1, 00:00:13, Serial0/0
This output shows that by configuring R2 as ODR; R1 (spoke) gets default route toward hub (R2)
R2#show ip route
C 1.0.0.0/8 is directly connected, FastEthernet0/0
C 2.0.0.0/8 is directly connected, Serial0/0
40.0.0.0/32 is subnetted, 2 subnets
o 40.1.1.1 [160/1] via 2.2.2.2, 00:00:30, Serial0/0
o 40.1.1.2 [160/1] via 2.2.2.2, 00:00:30, Serial0/0
R2 has learnt both ODR routes from CDP update
R1#show ip route
C 1.0.0.0/8 is directly connected, FastEthernet0/0
40.0.0.0/32 is subnetted, 2 subnets
D EX 40.1.1.1 [170/256028160] via 1.1.1.2, 00:00:37, FastEthernet0/0
D EX 40.1.1.2 [170/256028160] via 1.1.1.2, 00:00:37, FastEthernet0/0
Redistributed ODR routes to EIGRP
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