OSPF Non-Broadcast Networks

OSPF – Hub and spoke Topology

Dans une architecture « Hub and spoke » Frame relay, les interfaces peuvent être configurées dans 4 modes de communication OSPF :

R1(config)#int s0/0
R1(config-if)#ip ospf network ?
broadcast       Specify OSPF broadcast multi-access network
non-broadcast       Specify OSPF NBMA network
point-to-multipoint Specify  OSPF point-to-multipoint network
point-to-point      Specify OSPF point-to-point network

Par défaut, les interfaces sérial sont en mode « Non-Broadcast »

Configuration basique de R1 (et des autres routeurs)

router ospf 1
 log-adjacency-changes
 network 1.1.1.1 0.0.0.0 area 0
 network 10.1.1.1 0.0.0.0 area 0

R1#show ip ospf interface 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 NON_BROADCAST, Cost: 64
  Transmit Delay is 1 sec, State WAITING, Priority 1
  No designated router on this network
  No backup designated router on this network
  Timer intervals configured, Hello 30, Dead 120, Wait 120, Retransmit 5
    oob-resync timeout 120
    Hello due in 00:00:12
    Wait time before Designated router selection 00:01:12
  Supports Link-local Signaling (LLS)
  Index 2/2, flood queue length 0
  Next 0x0(0)/0x0(0)
  Last flood scan length is 0, maximum is 0
  Last flood scan time is 0 msec, maximum is 0 msec
  Neighbor Count is 0, Adjacent neighbor count is 0
  Suppress hello for 0 neighbor(s)

Dans cette configuration, les voisins OSPF doivent être spécifiés sur le routeur hub :

R1#conf t
R1(config)#router ospf 1
R1(config-router)#
R1(config-router)#neighbor 10.1.1.2
R1(config-router)#neighbor 10.1.1.3
R1(config-router)#neighbor 10.1.1.4

Vérifications:

R1#show ip ospf neighbor

Neighbor ID     Pri   State           Dead Time   Address         Interface
4.4.4.4           0   FULL/DROTHER    968 msec    10.1.1.4        Serial0/0
3.3.3.3           0   FULL/DROTHER    932 msec    10.1.1.3        Serial0/0
2.2.2.2           0   FULL/DROTHER    944 msec    10.1.1.2        Serial0/0

  
R1#show ip route ospf
O    2.0.0.0/8 [110/65] via 10.1.1.2, 00:00:45, Serial0/0
O    3.0.0.0/8 [110/65] via 10.1.1.3, 00:00:45, Serial0/0
O    4.0.0.0/8 [110/65] via 10.1.1.4, 00:00:45, Serial0/0