David Sudjiman

This is the simplest network type for OSPF. Two routers connected via point-to-point link. For this particular network, there is no need to have DR and BDR. Why, because each router will sending updates to each other and having DR and BDR will not change the situation. Each router will send multicast hello packets using address 224.0.0.5.

Default OSPF hello and dead intervals is 10 seconds and 40 seconds, respectively.

• Partial-mesh or star network topology, using subinterface.
• Different subnet for each subinterface.
• Hello Timer 10 seconds.
• Automatic adjacency, no DR/BDR elected.

R1#sh run | b 1/0
interface Serial1/0
 no ip address
 encapsulation frame-relay
 serial restart-delay 0
!
interface Serial1/0.102 point-to-point
 ip address 192.168.102.1 255.255.255.252
 ip ospf network point-to-point
 snmp trap link-status
 frame-relay interface-dlci 102
!
interface Serial1/0.103 point-to-point
 ip address 192.168.103.1 255.255.255.252
 ip ospf network point-to-point
 snmp trap link-status
 frame-relay interface-dlci 103   

R1#sh ip ospf nei

Neighbor ID     Pri   State           Dead Time   Address         Interface
3.3.3.3           0   FULL/  -        00:00:34    192.168.103.2   Serial1/0.103
2.2.2.2           0   FULL/  -        00:00:32    192.168.102.2   Serial1/0.102

R1#sh ip ospf int s1/0.102
Serial1/0.102 is up, line protocol is up
  Internet Address 192.168.102.1/30, Area 0
  Process ID 1, Router ID 1.1.1.1, Network Type POINT_TO_POINT, Cost: 64
  Transmit Delay is 1 sec, State POINT_TO_POINT,
  Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5
    oob-resync timeout 40
    Hello due in 00:00:06
  Supports Link-local Signaling (LLS)
  Index 2/2, flood queue length 0
  Next 0×0(0)/0×0(0)
  Last flood scan length is 1, maximum is 1
  Last flood scan time is 0 msec, maximum is 4 msec
  Neighbor Count is 1, Adjacent neighbor count is 1
    Adjacent with neighbor 2.2.2.2
  Suppress hello for 0 neighbor(s)

R1#sh ip ospf int s1/0.103
Serial1/0.103 is up, line protocol is up
  Internet Address 192.168.103.1/30, Area 0
  Process ID 1, Router ID 1.1.1.1, Network Type POINT_TO_POINT, Cost: 64
  Transmit Delay is 1 sec, State POINT_TO_POINT,
  Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5
    oob-resync timeout 40
    Hello due in 00:00:04
  Supports Link-local Signaling (LLS)
  Index 3/3, flood queue length 0
  Next 0×0(0)/0×0(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 3.3.3.3
  Suppress hello for 0 neighbor(s)

R2#debug ip ospf hello
OSPF hello events debugging is on
R2#
*Mar  1 04:48:33.414: OSPF: Rcv hello from 1.1.1.1 area 0 from Serial1/0.201 192.168.102.1
*Mar  1 04:48:33.418: OSPF: End of hello processing
*Mar  1 04:48:37.458: OSPF: Send hello to 224.0.0.5 area 0 on Serial1/0.201 from 192.168.102.2
*Mar  1 04:48:37.462: OSPF: Send hello to 224.0.0.5 area 0 on Serial1/0.203 from 192.168.203.1
*Mar  1 04:48:41.002: OSPF: Rcv hello from 3.3.3.3 area 0 from Serial1/0.203 192.168.203.2
*Mar  1 04:48:41.002: OSPF: End of hello processing

R2#sh run | b 1/0
interface Serial1/0
 no ip address
 encapsulation frame-relay
!
interface Serial1/0.201 point-to-point
 ip address 192.168.102.2 255.255.255.252
 ip ospf network point-to-point
 snmp trap link-status
 frame-relay interface-dlci 201
!
interface Serial1/0.203 point-to-point
 ip address 192.168.203.1 255.255.255.252
 ip ospf network point-to-point
 snmp trap link-status
 frame-relay interface-dlci 203   

R2#sh ip ospf nei

Neighbor ID     Pri   State           Dead Time   Address         Interface
3.3.3.3           0   FULL/  -        00:00:33    192.168.203.2   Serial1/0.203
1.1.1.1           0   FULL/  -        00:00:35    192.168.102.1   Serial1/0.201

R2#sh ip ospf int s1/0.201
Serial1/0.201 is up, line protocol is up
  Internet Address 192.168.102.2/30, Area 0
  Process ID 1, Router ID 2.2.2.2, Network Type POINT_TO_POINT, Cost: 64
  Transmit Delay is 1 sec, State POINT_TO_POINT,
  Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5
    oob-resync timeout 40
    Hello due in 00:00:09
  Supports Link-local Signaling (LLS)
  Index 2/2, flood queue length 0
  Next 0×0(0)/0×0(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
  Suppress hello for 0 neighbor(s)

R2#sh ip ospf int s1/0.203
Serial1/0.203 is up, line protocol is up
  Internet Address 192.168.203.1/30, Area 0
  Process ID 1, Router ID 2.2.2.2, Network Type POINT_TO_POINT, Cost: 64
  Transmit Delay is 1 sec, State POINT_TO_POINT,
  Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5
    oob-resync timeout 40
    Hello due in 00:00:07
  Supports Link-local Signaling (LLS)
  Index 3/3, flood queue length 0
  Next 0×0(0)/0×0(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 3.3.3.3
  Suppress hello for 0 neighbor(s)

R3#sh run | b 1/0
interface Serial1/0
 no ip address
 encapsulation frame-relay
 serial restart-delay 0
!
interface Serial1/0.301 point-to-point
 ip address 192.168.103.2 255.255.255.252
 ip ospf network point-to-point
 snmp trap link-status
 frame-relay interface-dlci 301
!
interface Serial1/0.302 point-to-point
 ip address 192.168.203.2 255.255.255.252
 ip ospf network point-to-point
 snmp trap link-status
 frame-relay interface-dlci 302   

R3#sh ip ospf nei

Neighbor ID     Pri   State           Dead Time   Address         Interface
2.2.2.2           0   FULL/  -        00:00:39    192.168.203.1   Serial1/0.302
1.1.1.1           0   FULL/  -        00:00:36    192.168.103.1   Serial1/0.301

R3#sh ip ospf int s1/0.301
Serial1/0.301 is up, line protocol is up
  Internet Address 192.168.103.2/30, Area 0
  Process ID 1, Router ID 3.3.3.3, Network Type POINT_TO_POINT, Cost: 64
  Transmit Delay is 1 sec, State POINT_TO_POINT,
  Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5
    oob-resync timeout 40
    Hello due in 00:00:01
  Supports Link-local Signaling (LLS)
  Index 2/2, flood queue length 0
  Next 0×0(0)/0×0(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
  Suppress hello for 0 neighbor(s)

R3#sh ip ospf int s1/0.302
Serial1/0.302 is up, line protocol is up
  Internet Address 192.168.203.2/30, Area 0
  Process ID 1, Router ID 3.3.3.3, Network Type POINT_TO_POINT, Cost: 64
  Transmit Delay is 1 sec, State POINT_TO_POINT,
  Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5
    oob-resync timeout 40
    Hello due in 00:00:00
  Supports Link-local Signaling (LLS)
  Index 3/3, flood queue length 0
  Next 0×0(0)/0×0(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 2.2.2.2
  Suppress hello for 0 neighbor(s)