Une priorité peut être configurée pour facilité l’élection du « Designated Router » (DR)
Dans une architecture « hub and spoke » en mode broadcast le routeur « hub » doit être élue DR en lui assignant la plus forte priorité(255), les routeur « spoke » doivent être configuré avec un priorité de 0
Configuration du routeur « hub » (R1)
R1(config)#int s0/0
R1(config-if)#ip ospf priority 255
Configuration des routeurs spoke (R2 à R4)
R4(config)#int s0/0
R4(config-if)#ip ospf priority 0
Vérifications:
R1#show ip ospf int s0/0 Serial0/0 is up, line protocol is up Internet Address 10.1.1.1/24, Area 0 Process ID 1, Router ID 1.1.1.1, Network Type BROADCAST, Cost: 64 Transmit Delay is 1 sec, State DR, Priority 255 Designated Router (ID) 1.1.1.1, Interface address 10.1.1.1 No backup designated router on this network Old designated Router (ID) 4.4.4.4, Interface address 10.1.1.4 Timer intervals configured, Hello 5, Dead 20, Wait 20, Retransmit 5 oob-resync timeout 40 Hello due in 00:00:04 Supports Link-local Signaling (LLS) Index 2/2, flood queue length 0 Next 0x0(0)/0x0(0) Last flood scan length is 1, maximum is 1 Last flood scan time is 0 msec, maximum is 4 msec Neighbor Count is 3, Adjacent neighbor count is 3 Adjacent with neighbor 2.2.2.2 Adjacent with neighbor 3.3.3.3 Adjacent with neighbor 4.4.4.4 Suppress hello for 0 neighbor(s)
R4#show ip ospf int s0/0 Serial0/0 is up, line protocol is up Internet Address 10.1.1.4/24, Area 0 Process ID 1, Router ID 4.4.4.4, Network Type BROADCAST, Cost: 64 Transmit Delay is 1 sec, State DROTHER, Priority 0 Designated Router (ID) 1.1.1.1, Interface address 10.1.1.1 No backup designated router on this network Old designated Router (ID) 4.4.4.4, Interface address 10.1.1.4 Flush timer for old DR LSA due in 00:00:36 Timer intervals configured, Hello 5, Dead 20, Wait 20, Retransmit 5 oob-resync timeout 40 Hello due in 00:00:03 Supports Link-local Signaling (LLS) Index 2/2, flood queue length 0 Next 0x0(0)/0x0(0) Last flood scan length is 1, maximum is 1 Last flood scan time is 0 msec, maximum is 0 msec Neighbor Count is 1, Adjacent neighbor count is 1 Adjacent with neighbor 1.1.1.1 (Designated Router) Suppress hello for 0 neighbor(s)