On-Demand Routing (ODR)

O ODR não deve ser encarado como um protocolo de routing mas sim uma extensão ao Cisco CDP. Através das mensagens recebidas do CDP de um neighbor, como o prefix/mask, pode assim redistribuir  estas redes em processos de routing. O ODR suporta Variable Length Subnet Mask (VLSM). Ao ativar o ODR os neighbors são “vistos” como stub, recebendo a default route.

AD=160
Timers:  Updates a cada 60 segundos, Invalid 180 segundos, flushed 240 segundos

Exemplo:

Ligações:

R2-f0/1—–f0/0-R3

R2#
*Mar  1 14:45:22.532: CDP-IP: Writing default route 192.168.20.2 for FastEthernet0/1
*Mar  1 14:45:36.116: CDP-IP: Reading prefix 10.100.100.0/24 source 192.168.20.1 via FastEthernet0/1
*Mar  1 14:45:36.120: CDP-IP: Updating prefix 10.100.100.0/24 in routing table
*Mar  1 14:45:36.124: CDP-IP: Reading prefix 10.100.200.0/24 source 192.168.20.1 via FastEthernet0/1
*Mar  1 14:45:36.124: CDP-IP: Updating prefix 10.100.200.0/24 in routing table
R2#
*Mar  1 14:45:39.956: CDP-IP: Aging routes

R2#sh ip route od
10.0.0.0/24 is subnetted, 3 subnets
o       10.100.100.0 [160/1] via 192.168.20.1, 00:00:07, FastEthernet0/1
o       10.100.200.0 [160/1] via 192.168.20.1, 00:00:07, FastEthernet0/1

R2(config)#
router ospf 1
redistribute odr subnets

router odr
redistribute ospf 1
redistribution of “ospf” via “odr” not allowe

R2#sh ip pro
Routing Protocol is “odr”
Sending updates every 60 seconds, next due in 56 seconds
  Invalid after 180 seconds, hold down 0, flushed after 240
Outgoing update filter list for all interfaces is not set
Incoming update filter list for all interfaces is not set
Maximum path: 4
Routing Information Sources:
Gateway         Distance      Last Update
192.168.20.1         160      00:00:07
  Distance: (default is 160)

R3#sh ip int br
Interface                  IP-Address      OK? Method Status                Protocol
FastEthernet0/0            192.168.20.1    YES manual up                    up
Loopback1                  10.100.100.1    YES manual up                    up
Loopback2                  10.100.200.1    YES manual up                    up

R3#sh ip ro od
o*   0.0.0.0/0 [160/1] via 192.168.20.2, 00:00:07, FastEthernet0/0

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