OSPF Network Type – Broadcast

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Points to remember about Broadcast OSPF network type.

1. Designated Router (DR) and Back Designated Router(BDR) election occurs. BDR sends LS to multicast address 2240.0.6 which is the DR and DR sends LS to multicast address 224.0.0.5 which is all routers within the area.
2. No pre-emption meaning when the DR goes down, BDR takes DR responsibility but when DR comes backup it won’t become the DR.
3. DR/BDR election process is based on the following criterias:
3a. Highest Router ID (RID).
3b. Highest IP address assigned on a loopback interface.
3c. Highest IP address assigned on a non-loopback (physical) interface.
4. Default network type on broadcast media like Ethernet.

DR/BDR election scenario 1: IP address assigned on physical interface.

         .-----.               .-----.
         | R01 |               | R02 |
         '-----'               '-----'
            |                     |
            | F0/0 (.1)           | F0/0 (.2)
            v                     v
     =================================== Switch-10.0.0.0/24
                       ^
                       | F0/0 (.3)
                       |
                    .-----.
                    | R03 |
                    '-----'

IP OSPF logs taken from R02.

R02 detects two OSPF adjacencies – R01 and R03.

*Mar  1 00:12:44.339: OSPF: 2 Way Communication to 10.0.0.3 on FastEthernet0/0, state 2WAY
*Mar  1 00:12:44.343: OSPF: 2 Way Communication to 10.0.0.1 on FastEthernet0/0, state 2WAY
*Mar  1 00:13:14.303: OSPF: end of Wait on interface FastEthernet0/0
*Mar  1 00:13:14.303: OSPF: DR/BDR election on FastEthernet0/0 
*Mar  1 00:13:14.303: OSPF: Elect BDR 10.0.0.3
*Mar  1 00:13:14.303: OSPF: Elect DR 10.0.0.3
*Mar  1 00:13:14.303:        DR: 10.0.0.3 (Id)   BDR: 10.0.0.3 (Id)
*Mar  1 00:13:14.307: OSPF: Send DBD to 10.0.0.3 on FastEthernet0/0 seq 0xD9E opt 0x52 flag 0x7 len 32
*Mar  1 00:13:14.671: OSPF: Rcv DBD from 10.0.0.3 on FastEthernet0/0 seq 0x20DC opt 0x52 flag 0x7 len 32  mtu 1500 state EXSTART
*Mar  1 00:13:14.671: OSPF: NBR Negotiation Done. We are the SLAVE
*Mar  1 00:13:14.675: OSPF: Send DBD to 10.0.0.3 on FastEthernet0/0 seq 0x20DC opt 0x52 flag 0x2 len 112
*Mar  1 00:13:14.691: OSPF: Neighbor change Event on interface FastEthernet0/0

Election process occurs. R03 elected as DR because it has the highest IP address while R02 elected as BDR with the second highest IP address.

*Mar  1 00:13:14.691: OSPF: DR/BDR election on FastEthernet0/0 
*Mar  1 00:13:14.691: OSPF: Elect BDR 10.0.0.2
*Mar  1 00:13:14.691: OSPF: Elect DR 10.0.0.3
*Mar  1 00:13:14.695: OSPF: Elect BDR 10.0.0.2
*Mar  1 00:13:14.695: OSPF: Elect DR 10.0.0.3
*Mar  1 00:13:14.695:        DR: 10.0.0.3 (Id)   BDR: 10.0.0.2 (Id)
*Mar  1 00:13:14.695: OSPF: Send DBD to 10.0.0.1 on FastEthernet0/0 seq 0x157 opt 0x52 flag 0x7 len 32
*Mar  1 00:13:14.699: OSPF: Neighbor change Event on interface FastEthernet0/0
*Mar  1 00:13:14.699: OSPF: DR/BDR election on FastEthernet0/0 
*Mar  1 00:13:14.699: OSPF: Elect BDR 10.0.0.2
*Mar  1 00:13:14.699: OSPF: Elect DR 10.0.0.3
*Mar  1 00:13:14.699:        DR: 10.0.0.3 (Id)   BDR: 10.0.0.2 (Id)
*Mar  1 00:13:14.703: OSPF: Rcv DBD from 10.0.0.3 on FastEthernet0/0 seq 0x20DD opt 0x52 flag 0x3 len 92  mtu 1500 state EXCHANGE
*Mar  1 00:13:14.703: OSPF: Send DBD to 10.0.0.3 on FastEthernet0/0 seq 0x20DD opt 0x52 flag 0x0 len 32
*Mar  1 00:13:14.723: OSPF: Rcv DBD from 10.0.0.3 on FastEthernet0/0 seq 0x20DE opt 0x52 flag 0x1 len 32  mtu 1500 state EXCHANGE
*Mar  1 00:13:14.723: OSPF: Exchange Done with 10.0.0.3 on FastEthernet0/0
*Mar  1 00:13:14.727: OSPF: Send LS REQ to 10.0.0.3 length 12 LSA count 1
*Mar  1 00:13:14.727: OSPF: Send DBD to 10.0.0.3 on FastEthernet0/0 seq 0x20DE opt 0x52 flag 0x0 len 32
*Mar  1 00:13:14.735: OSPF: Rcv LS REQ from 10.0.0.3 on FastEthernet0/0 length 48 LSA count 2
*Mar  1 00:13:14.735: OSPF: Send UPD to 10.0.0.3 on FastEthernet0/0 length 76 LSA count 2
*Mar  1 00:13:14.747: OSPF: Rcv LS UPD from 10.0.0.3 on FastEthernet0/0 length 64 LSA count 1
*Mar  1 00:13:14.747: OSPF: Synchronized with 10.0.0.3 on FastEthernet0/0, state FULL
*Mar  1 00:13:14.747: %OSPF-5-ADJCHG: Process 1, Nbr 10.0.0.3 on FastEthernet0/0 from LOADING to FULL, Loading Done
*Mar  1 00:13:14.763: OSPF: Rcv LS UPD from 10.0.0.3 on FastEthernet0/0 length 64 LSA count 1
*Mar  1 00:13:14.787: OSPF: Rcv LS UPD from 10.0.0.3 on FastEthernet0/0 length 64 LSA count 1
*Mar  1 00:13:14.807: OSPF: Build router LSA for area 0, router ID 10.0.0.2, seq 0x80000005
*Mar  1 00:13:14.827: OSPF: Rcv LS UPD from 10.0.0.3 on FastEthernet0/0 length 64 LSA count 1
*Mar  1 00:13:15.039: OSPF: Rcv DBD from 10.0.0.1 on FastEthernet0/0 seq 0xFB opt 0x52 flag 0x7 len 32  mtu 1500 state EXSTART
*Mar  1 00:13:15.039: OSPF: First DBD and we are not SLAVE
*Mar  1 00:13:15.055: OSPF: Neighbor change Event on interface FastEthernet0/0
*Mar  1 00:13:15.055: OSPF: DR/BDR election on FastEthernet0/0 
*Mar  1 00:13:15.055: OSPF: Elect BDR 10.0.0.2
*Mar  1 00:13:15.059: OSPF: Elect DR 10.0.0.3
*Mar  1 00:13:15.059:        DR: 10.0.0.3 (Id)   BDR: 10.0.0.2 (Id)
*Mar  1 00:13:15.059: OSPF: Neighbor change Event on interface FastEthernet0/0
*Mar  1 00:13:15.059: OSPF: DR/BDR election on FastEthernet0/0 
*Mar  1 00:13:15.059: OSPF: Elect BDR 10.0.0.2
*Mar  1 00:13:15.059: OSPF: Elect DR 10.0.0.3
*Mar  1 00:13:15.063:        DR: 10.0.0.3 (Id)   BDR: 10.0.0.2 (Id)
*Mar  1 00:13:15.187: OSPF: Rcv LS UPD from 10.0.0.3 on FastEthernet0/0 length 64 LSA count 1
*Mar  1 00:13:19.699: OSPF: Send DBD to 10.0.0.1 on FastEthernet0/0 seq 0x157 opt 0x52 flag 0x7 len 32
*Mar  1 00:13:19.699: OSPF: Retransmitting DBD to 10.0.0.1 on FastEthernet0/0 [1]
*Mar  1 00:13:19.719: OSPF: Rcv DBD from 10.0.0.1 on FastEthernet0/0 seq 0x157 opt 0x52 flag 0x2 len 112  mtu 1500 state EXSTART
*Mar  1 00:13:19.719: OSPF: NBR Negotiation Done. We are the MASTER
*Mar  1 00:13:19.719: OSPF: Send DBD to 10.0.0.1 on FastEthernet0/0 seq 0x158 opt 0x52 flag 0x3 len 92
*Mar  1 00:13:19.751: OSPF: Rcv LS UPD from 10.0.0.3 on FastEthernet0/0 length 64 LSA count 1
*Mar  1 00:13:19.755: OSPF: Rcv DBD from 10.0.0.1 on FastEthernet0/0 seq 0x158 opt 0x52 flag 0x0 len 32  mtu 1500 state EXCHANGE
*Mar  1 00:13:19.755: OSPF: Send DBD to 10.0.0.1 on FastEthernet0/0 seq 0x159 opt 0x52 flag 0x1 len 32
*Mar  1 00:13:19.779: OSPF: Rcv DBD from 10.0.0.1 on FastEthernet0/0 seq 0x159 opt 0x52 flag 0x0 len 32  mtu 1500 state EXCHANGE
*Mar  1 00:13:19.779: OSPF: Exchange Done with 10.0.0.1 on FastEthernet0/0
*Mar  1 00:13:19.779: OSPF: Synchronized with 10.0.0.1 on FastEthernet0/0, state FULL
*Mar  1 00:13:19.779: %OSPF-5-ADJCHG: Process 1, Nbr 10.0.0.1 on FastEthernet0/0 from LOADING to FULL, Loading Done
*Mar  1 00:13:19.787: OSPF: Rcv LS UPD from 10.0.0.3 on FastEthernet0/0 length 64 LSA count 1
*Mar  1 00:13:20.275: OSPF: Rcv LS UPD from 10.0.0.1 on FastEthernet0/0 length 64 LSA count 1
*Mar  1 00:13:20.283: OSPF: Rcv LS UPD from 10.0.0.3 on FastEthernet0/0 length 64 LSA count 1

DR/BDR election scenario 2: IP address assigned on physical and loopback interface.

         Lo:11.11.11.11       Lo:2.2.2.2
         .-----.               .-----.
         | R01 |               | R02 |
         '-----'               '-----'
            |                     |
            | F0/0 (.1)           | F0/0 (.2)
            v                     v
     =================================== Switch-10.0.0.0/24
                       ^
                       | F0/0 (.3)
                       |
                    .-----.
                    | R03 |
                    '-----'
                  Lo:3.3.3.3

IP OSPF logs taken from R02.

R02 detects two OSPF adjacencies – R01 and R03. Now the loopback IP addresses are used not the physical interface IP addresses.

*Mar  1 00:42:13.507: OSPF: Interface FastEthernet0/0 going Up
*Mar  1 00:42:13.507: OSPF: Interface Loopback0 going Up
*Mar  1 00:42:13.527: OSPF: 2 Way Communication to 3.3.3.3 on FastEthernet0/0, state 2WAY
*Mar  1 00:42:13.971: OSPF: 2 Way Communication to 11.11.11.11 on FastEthernet0/0, state 2WAY

Election process occurs. R01 elected as DR because it has the highest IP address while R03 elected as BDR with the second highest IP address.

*Mar  1 00:42:14.007: OSPF: Build router LSA for area 0, router ID 2.2.2.2, seq 0x80000001
*Mar  1 00:42:53.507: OSPF: end of Wait on interface FastEthernet0/0
*Mar  1 00:42:53.507: OSPF: DR/BDR election on FastEthernet0/0 
*Mar  1 00:42:53.507: OSPF: Elect BDR 11.11.11.11
*Mar  1 00:42:53.507: OSPF: Elect DR 11.11.11.11
*Mar  1 00:42:53.507:        DR: 11.11.11.11 (Id)   BDR: 11.11.11.11 (Id)
*Mar  1 00:42:53.511: OSPF: Send DBD to 11.11.11.11 on FastEthernet0/0 seq 0x26F6 opt 0x52 flag 0x7 len 32
*Mar  1 00:42:53.975: OSPF: Rcv DBD from 11.11.11.11 on FastEthernet0/0 seq 0x481 opt 0x52 flag 0x7 len 32  mtu 1500 state EXSTART
*Mar  1 00:42:53.975: OSPF: NBR Negotiation Done. We are the SLAVE
*Mar  1 00:42:53.975: OSPF: Send DBD to 11.11.11.11 on FastEthernet0/0 seq 0x481 opt 0x52 flag 0x2 len 52
*Mar  1 00:42:53.991: OSPF: Neighbor change Event on interface FastEthernet0/0
*Mar  1 00:42:53.991: OSPF: DR/BDR election on FastEthernet0/0 
*Mar  1 00:42:53.991: OSPF: Elect BDR 3.3.3.3
*Mar  1 00:42:53.991: OSPF: Elect DR 11.11.11.11
*Mar  1 00:42:53.995:        DR: 11.11.11.11 (Id)   BDR: 3.3.3.3 (Id)
*Mar  1 00:42:53.995: OSPF: Send DBD to 3.3.3.3 on FastEthernet0/0 seq 0x42C opt 0x52 flag 0x7 len 32
*Mar  1 00:42:53.995: OSPF: Neighbor change Event on interface FastEthernet0/0
*Mar  1 00:42:53.995: OSPF: DR/BDR election on FastEthernet0/0 
*Mar  1 00:42:53.995: OSPF: Elect BDR 3.3.3.3
*Mar  1 00:42:53.995: OSPF: Elect DR 11.11.11.11
*Mar  1 00:42:53.995:        DR: 11.11.11.11 (Id)   BDR: 3.3.3.3 (Id)
*Mar  1 00:42:54.003: OSPF: Rcv DBD from 3.3.3.3 on FastEthernet0/0 seq 0x1556 opt 0x52 flag 0x7 len 32  mtu 1500 state EXSTART
*Mar  1 00:42:54.007: OSPF: NBR Negotiation Done. We are the SLAVE
*Mar  1 00:42:54.007: OSPF: Send DBD to 3.3.3.3 on FastEthernet0/0 seq 0x1556 opt 0x52 flag 0x2 len 52
*Mar  1 00:42:54.007: OSPF: Rcv DBD from 11.11.11.11 on FastEthernet0/0 seq 0x482 opt 0x52 flag 0x3 len 52  mtu 1500 state EXCHANGE
*Mar  1 00:42:54.007: OSPF: Send DBD to 11.11.11.11 on FastEthernet0/0 seq 0x482 opt 0x52 flag 0x0 len 32
*Mar  1 00:42:54.023: OSPF: Rcv DBD from 3.3.3.3 on FastEthernet0/0 seq 0x1557 opt 0x52 flag 0x3 len 52  mtu 1500 state EXCHANGE
*Mar  1 00:42:54.023: OSPF: Send DBD to 3.3.3.3 on FastEthernet0/0 seq 0x1557 opt 0x52 flag 0x0 len 32
*Mar  1 00:42:54.035: OSPF: Rcv DBD from 11.11.11.11 on FastEthernet0/0 seq 0x483 opt 0x52 flag 0x1 len 32  mtu 1500 state EXCHANGE
*Mar  1 00:42:54.039: OSPF: Exchange Done with 11.11.11.11 on FastEthernet0/0
*Mar  1 00:42:54.039: OSPF: Send LS REQ to 11.11.11.11 length 12 LSA count 1
*Mar  1 00:42:54.039: OSPF: Send DBD to 11.11.11.11 on FastEthernet0/0 seq 0x483 opt 0x52 flag 0x0 len 32
*Mar  1 00:42:54.047: OSPF: Rcv DBD from 3.3.3.3 on FastEthernet0/0 seq 0x1558 opt 0x52 flag 0x1 len 32  mtu 1500 state EXCHANGE
*Mar  1 00:42:54.047: OSPF: Exchange Done with 3.3.3.3 on FastEthernet0/0
*Mar  1 00:42:54.047: OSPF: Send LS REQ to 3.3.3.3 length 12 LSA count 1
*Mar  1 00:42:54.047: OSPF: Send DBD to 3.3.3.3 on FastEthernet0/0 seq 0x1558 opt 0x52 flag 0x0 len 32
*Mar  1 00:42:54.047: OSPF: Rcv LS REQ from 11.11.11.11 on FastEthernet0/0 length 36 LSA count 1
*Mar  1 00:42:54.047: OSPF: Send UPD to 10.0.0.1 on FastEthernet0/0 length 52 LSA count 1
*Mar  1 00:42:54.055: OSPF: Rcv LS REQ from 3.3.3.3 on FastEthernet0/0 length 36 LSA count 1
*Mar  1 00:42:54.055: OSPF: Send UPD to 10.0.0.3 on FastEthernet0/0 length 52 LSA count 1
*Mar  1 00:42:54.075: OSPF: Rcv LS UPD from 11.11.11.11 on FastEthernet0/0 length 76 LSA count 1
*Mar  1 00:42:54.079: OSPF: Synchronized with 11.11.11.11 on FastEthernet0/0, state FULL
*Mar  1 00:42:54.079: %OSPF-5-ADJCHG: Process 1, Nbr 11.11.11.11 on FastEthernet0/0 from LOADING to FULL, Loading Done
*Mar  1 00:42:54.087: OSPF: Rcv LS UPD from 3.3.3.3 on FastEthernet0/0 length 76 LSA count 1
*Mar  1 00:42:54.087: OSPF: Synchronized with 3.3.3.3 on FastEthernet0/0, state FULL
*Mar  1 00:42:54.087: %OSPF-5-ADJCHG: Process 1, Nbr 3.3.3.3 on FastEthernet0/0 from LOADING to FULL, Loading Done
*Mar  1 00:42:54.095: OSPF: Rcv LS UPD from 11.11.11.11 on FastEthernet0/0 length 76 LSA count 1
*Mar  1 00:42:54.147: OSPF: Rcv LS UPD from 11.11.11.11 on FastEthernet0/0 length 76 LSA count 1
*Mar  1 00:42:54.467: OSPF: Rcv LS UPD from 11.11.11.11 on FastEthernet0/0 length 76 LSA count 1
*Mar  1 00:42:54.491: OSPF: Rcv LS UPD from 11.11.11.11 on FastEthernet0/0 length 64 LSA count 1
*Mar  1 00:42:54.531: OSPF: Rcv LS UPD from 3.3.3.3 on FastEthernet0/0 length 76 LSA count 1
*Mar  1 00:42:54.543: OSPF: Rcv LS UPD from 11.11.11.11 on FastEthernet0/0 length 76 LSA count 1
*Mar  1 00:42:54.579: OSPF: Build router LSA for area 0, router ID 2.2.2.2, seq 0x80000002
*Mar  1 00:42:54.603: OSPF: Rcv LS UPD from 11.11.11.11 on FastEthernet0/0 length 76 LSA count 1
*Mar  1 00:43:03.059: OSPF: Neighbor change Event on interface FastEthernet0/0
*Mar  1 00:43:03.063: OSPF: DR/BDR election on FastEthernet0/0 
*Mar  1 00:43:03.063: OSPF: Elect BDR 3.3.3.3
*Mar  1 00:43:03.063: OSPF: Elect DR 11.11.11.11
*Mar  1 00:43:03.063:        DR: 11.11.11.11 (Id)   BDR: 3.3.3.3 (Id)

DR/BDR election scenario 3: Routers configured with Router ID (RID) and IP address on loopback and non-loopback interfaces.

       Lo:11.11.11.11         Lo:2.2.2.2
       RID: 1.1.1.1        RID: 22.22.22.22
         .-----.               .-----.
         | R01 |               | R02 |
         '-----'               '-----'
            |                     |
            | F0/0 (.1)           | F0/0 (.2)
            v                     v
     =================================== Switch-10.0.0.0/24
                       ^
                       | F0/0 (.3)
                       |
                    .-----.
                    | R03 |
                    '-----'
                  Lo:3.3.3.3
                RID: 33.33.33.33

IP OSPF logs taken from R03.

R03 detects two OSPF adjacencies – R01 and R02. Now the Router IDs are used not the loopback and non-loopback interface IP addresses. R03 won the DR/BDR election process because it has the highest Router ID.

R3(config-if)#
*Mar  1 13:15:35.652: OSPF: Rcv DBD from 22.22.22.22 on FastEthernet0/0 seq 0xEC4 opt 0x52 flag 0x7 len 32  mtu 1500 state 2WAY
*Mar  1 13:15:35.652: OSPF: Nbr state is 2WAY
*Mar  1 13:15:36.772: OSPF: Rcv DBD from 1.1.1.1 on FastEthernet0/0 seq 0x1FA9 opt 0x52 flag 0x7 len 32  mtu 1500 state 2WAY
*Mar  1 13:15:36.772: OSPF: Nbr state is 2WAY
*Mar  1 13:15:37.456: OSPF: end of Wait on interface FastEthernet0/0
*Mar  1 13:15:37.456: OSPF: DR/BDR election on FastEthernet0/0 
*Mar  1 13:15:37.456: OSPF: Elect BDR 33.33.33.33
*Mar  1 13:15:37.456: OSPF: Elect DR 33.33.33.33
*Mar  1 13:15:37.456: OSPF: Elect BDR 22.22.22.22
R3(config-if)#37.456: OSPF: Elect DR 33.33.33.33
*Mar  1 13:15:37.460:        DR: 33.33.33.33 (Id)   BDR: 22.22.22.22 (Id)
*Mar  1 13:15:37.460: OSPF: Send DBD to 1.1.1.1 on FastEthernet0/0 seq 0x2306 opt 0x52 flag 0x7 len 32
*Mar  1 13:15:37.460: OSPF: Send DBD to 22.22.22.22 on FastEthernet0/0 seq 0x187A opt 0x52 flag 0x7 len 32
*Mar  1 13:15:37.488: OSPF: Rcv DBD from 1.1.1.1 on FastEthernet0/0 seq 0x2306 opt 0x52 flag 0x2 len 132  mtu 1500 state EXSTART
*Mar  1 13:15:37.488: OSPF: NBR Negotiation Done. We are the MASTER
*Mar  1 13:15:37.488: OSPF: Send DBD to 1.1.1.1 on FastEthernet0/0 seq 0x2307 opt 0x52 flag 0x3 len 112
*Mar  1 13:15:37.500: OSPF: Rcv DBD from 22.22.22.22 on FastEthernet0/0 seq 0x187A opt 0x52 flag 0x2 len 132  mtu 1500 state EXSTART
*Mar  1 13:15:37.500: OSPF: NBR Negotiation Done. We are the MASTER
*Mar  1 13:15:37.500: OSPF: Send DBD to 22.22.22.22 on FastEthernet0/0 seq 0x187B opt 0x52 flag 0x3 len 112
*Mar  1 13:15:37.516: OSPF: Rcv DBD from 1.1.1.1 on FastEthernet0/0 seq 0x2307 opt 0x52 flag 0x0 len 32  mtu 1500 state EXCHANGE
*Mar  1 13:15:37.516: OSPF: Send DBD to 1.1.1.1 on FastEthernet0/0 seq 0x2308 opt 0x52 flag 0x1 len 32
*Mar  1 13:15:37.520: OSPF: Send LS REQ to 1.1.1.1 length 24 LSA count 2
*Mar  1 13:15:37.528: OSPF: Rcv DBD from 22.22.22.22 on FastEthernet0/0 seq 0x187B opt 0x52 flag 0x0 len 32  mtu 1500 state EXCHANGE
*Mar  1 13:15:37.528: OSPF: Send DBD to 22.22.22.22 on FastEthernet0/0 seq 0x187C opt 0x52 flag 0x1 len 32
*Mar  1 13:15:37.528: OSPF: Send LS REQ to 22.22.22.22 length 24 LSA count 2
*Mar  1 13:15:37.536: OSPF: Rcv LS REQ from 1.1.1.1 on FastEthernet0/0 length 36 LSA count 1
*Mar  1 13:15:37.536: OSPF: Send UPD to 10.0.0.1 on FastEthernet0/0 length 52 LSA count 1
*Mar  1 13:15:37.548: OSPF: Rcv DBD from 1.1.1.1 on FastEthernet0/0 seq 0x2308 opt 0x52 flag 0x0 len 32  mtu 1500 state EXCHANGE
*Mar  1 13:15:37.548: OSPF: Exchange Done with 1.1.1.1 on FastEthernet0/0
*Mar  1 13:15:37.556: OSPF: Rcv LS REQ from 22.22.22.22 on FastEthernet0/0 length 36 LSA count 1
*Mar  1 13:15:37.560: OSPF: Send UPD to 10.0.0.2 on FastEthernet0/0 length 52 LSA count 1
*Mar  1 13:15:37.560: OSPF: Rcv LS UPD from 1.1.1.1 on FastEthernet0/0 length 112 LSA count 2
*Mar  1 13:15:37.560: OSPF: No full nbrs to build Net Lsa for interface FastEthernet0/0
*Mar  1 13:15:37.560: OSPF: Build network LSA for FastEthernet0/0, router ID 33.33.33.33
*Mar  1 13:15:37.560: OSPF: Build network LSA for FastEthernet0/0, router ID 33.33.33.33
*Mar  1 13:15:37.560: OSPF: Synchronized with 1.1.1.1 on FastEthernet0/0, state FULL
*Mar  1 13:15:37.560: %OSPF-5-ADJCHG: Process 1, Nbr 1.1.1.1 on FastEthernet0/0 from LOADING to FULL, Loading Done
*Mar  1 13:15:37.568: OSPF: Rcv DBD from 22.22.22.22 on FastEthernet0/0 seq 0x187C opt 0x52 flag 0x0 len 32  mtu 1500 state EXCHANGE
*Mar  1 13:15:37.568: OSPF: Exchange Done with 22.22.22.22 on FastEthernet0/0
*Mar  1 13:15:37.580: OSPF: Rcv LS UPD from 22.22.22.22 on FastEthernet0/0 length 112 LSA count 2
*Mar  1 13:15:37.580: OSPF: Synchronized with 22.22.22.22 on FastEthernet0/0, state FULL
*Mar  1 13:15:37.580: %OSPF-5-ADJCHG: Process 1, Nbr 22.22.22.22 on FastEthernet0/0 from LOADING to FULL, Loading Done
*Mar  1 13:15:37.964: OSPF: Build router LSA for area 0, router ID 33.33.33.33, seq 0x80000005
*Mar  1 13:15:38.016: OSPF: Rcv LS UPD from 22.22.22.22 on FastEthernet0/0 length 76 LSA count 1
*Mar  1 13:15:38.020: OSPF: Rcv LS UPD from 1.1.1.1 on FastEthernet0/0 length 76 LSA count 1
R3(config-if)#42.560: OSPF: Build network LSA for FastEthernet0/0, router ID 33.33.33.33
*Mar  1 13:15:42.564: OSPF: Build network LSA for FastEthernet0/0, router ID 33.33.33.33
*Mar  1 13:15:42.684: OSPF: Rcv LS UPD from 1.1.1.1 on FastEthernet0/0 length 76 LSA count 1
*Mar  1 13:15:45.652: OSPF: Neighbor change Event on interface FastEthernet0/0
*Mar  1 13:15:45.656: OSPF: DR/BDR election on FastEthernet0/0 
*Mar  1 13:15:45.656: OSPF: Elect BDR 22.22.22.22
*Mar  1 13:15:45.656: OSPF: Elect DR 33.33.33.33
*Mar  1 13:15:45.656:        DR: 33.33.33.33 (Id)   BDR: 22.22.22.22 (Id)
*Mar  1 13:15:46.880: OSPF: Neighbor change Event on interface FastEthernet0/0
*Mar  1 13:15:46.880: OSPF: DR/BDR election on FastEthernet0/0 
*Mar  1 13:15:46.880: OSPF: Elect BDR 22.22.22.22
*Mar  1 13:15:46.880: OSPF: Elect DR 33.33.33.33
*Mar  1 13:15:46.880:        DR: 33.33.33.33 (Id)   BDR: 22.22.22.22 (Id)
*Mar  1 13:15:47.424: OSPF: Rcv LS UPD from 1.1.1.1 on FastEthernet0/0 length 76 LSA count 1

DR/BDR election scenario 4: DR goest down and BDR takes DR responsibility. Then the previous DR comes back up.

       Lo:11.11.11.11         Lo:2.2.2.2
       RID: 1.1.1.1        RID: 22.22.22.22
         .-----.               .-----.
         | R01 |               | R02 |
         '-----'               '-----'
            |                     |
            | F0/0 (.1)           | F0/0 (.2)
            v                     v
     =================================== Switch-10.0.0.0/24
                       ^
                       | F0/0 (.3)
                       |
                    .-----.
                    | R03 |
                    '-----'
                  Lo:3.3.3.3
                RID: 33.33.33.33

R03 goes down by shutting down F0/0 interface.

*Mar  1 13:25:52.420: OSPF: Interface FastEthernet0/0 going Down
*Mar  1 13:25:52.424: OSPF: 1.1.1.1 address 10.0.0.1 on FastEthernet0/0 is dead, state DOWN
*Mar  1 13:25:52.424: %OSPF-5-ADJCHG: Process 1, Nbr 1.1.1.1 on FastEthernet0/0 from FULL to DOWN, Neighbor Down: Interface down or detached
*Mar  1 13:25:52.424: OSPF: Neighbor change Event on interface FastEthernet0/0
*Mar  1 13:25:52.424: OSPF: DR/BDR election on FastEthernet0/0 
*Mar  1 13:25:52.428: OSPF: Elect BDR 22.22.22.22
*Mar  1 13:25:52.428: OSPF: Elect DR 33.33.33.33
*Mar  1 13:25:52.428:        DR: 33.33.33.33 (Id)   BDR: 22.22.22.22 (Id)
*Mar  1 13:25:52.428: OSPF: 22.22.22.22 address 10.0.0.2 on FastEthernet0/0 is dead, state DOWN
*Mar  1 13:25:52.428: %OSPF-5-ADJCHG: Process 1, Nbr 22.22.22.22 on FastEthernet0/0 from FULL to DOWN, Neighbor Down: Interface down or detached
*Mar  1 13:25:52.432: OSPF: Neighbor change Event on interface FastEthernet0/0
*Mar  1 13:25:52.432: OSPF: DR/BDR election on FastEthernet0/0 
*Mar  1 13:25:52.432: OSPF: Elect BDR 0.0.0.0
*Mar  1 13:25:52.432: OSPF: Elect DR 33.33.33.33
*Mar  1 13:25:52.432:        DR: 33.33.33.33 (Id)   BDR: none 
*Mar  1 13:25:52.436: OSPF: 33.33.33.33 address 10.0.0.3 on FastEthernet0/0 is dead, state DOWN
*Mar  1 13:25:52.436: OSPF: Neighbor change Event on interface FastEthernet0/0
*Mar  1 13:25:52.436: OSPF: DR/BDR election on FastEthernet0/0 
*Mar  1 13:25:52.436: OSPF: Elect BDR 0.0.0.0
*Mar  1 13:25:52.436: OSPF: Elect DR 0.0.0.0
*Mar  1 13:25:52.440: OSPF: Elect BDR 0.0.0.0
*Mar  1 13:25:52.440: OSPF: Elect DR 0.0.0.0
*Mar  1 13:25:52.440:        DR: none    BDR: none 
*Mar  1 13:25:52.440: OSPF: Flush network LSA immediately
*Mar  1 13:25:52.440: OSPF: Remember old DR 33.33.33.33 (id)
*Mar  1 13:25:52.924: OSPF: Build router LSA for area 0, router ID 33.33.33.33, seq 0x80000006
*Mar  1 13:25:52.924: OSPF: We are not DR to build Net Lsa for interface FastEthernet0/0
*Mar  1 13:25:52.924: OSPF: Build network LSA for FastEthernet0/0, router ID 33.33.33.33
*Mar  1 13:25:52.924: OSPF: Build network LSA for FastEthernet0/0, router ID 33.33.33.33
*Mar  1 13:25:54.416: %LINK-5-CHANGED: Interface FastEthernet0/0, changed state to administratively down
*Mar  1 13:25:55.416: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/0, changed state to down

R01 and R02 elect themselves. R02 becomes the new DR as it has the highest Router ID. R01 elected as the BDR.

*Mar  1 13:26:28.696: OSPF: 33.33.33.33 address 10.0.0.3 on FastEthernet0/0 is dead
*Mar  1 13:26:28.696: OSPF: 33.33.33.33 address 10.0.0.3 on FastEthernet0/0 is dead, state DOWN
*Mar  1 13:26:28.696: %OSPF-5-ADJCHG: Process 1, Nbr 33.33.33.33 on FastEthernet0/0 from FULL to DOWN, Neighbor Down: Dead timer expired
*Mar  1 13:26:28.696: OSPF: Neighbor change Event on interface FastEthernet0/0
*Mar  1 13:26:28.700: OSPF: DR/BDR election on FastEthernet0/0 
*Mar  1 13:26:28.700: OSPF: Elect BDR 22.22.22.22
*Mar  1 13:26:28.700: OSPF: Elect DR 22.22.22.22
*Mar  1 13:26:28.700: OSPF: Elect BDR 1.1.1.1
*Mar  1 13:26:28.700: OSPF: Elect DR 22.22.22.22
*Mar  1 13:26:28.700:        DR: 22.22.22.22 (Id)   BDR: 1.1.1.1 (Id)
*Mar  1 13:26:28.704: OSPF: Remember old DR 33.33.33.33 (id)
*Mar  1 13:26:29.188: OSPF: Rcv LS UPD from 1.1.1.1 on FastEthernet0/0 length 76 LSA count 1
*Mar  1 13:26:29.196: OSPF: Build router LSA for area 0, router ID 22.22.22.22, seq 0x80000008
*Mar  1 13:26:29.204: OSPF: Build network LSA for FastEthernet0/0, router ID 22.22.22.22
*Mar  1 13:26:29.204: OSPF: Build network LSA for FastEthernet0/0, router ID 22.22.22.22
*Mar  1 13:26:36.852: OSPF: Send hello to 224.0.0.5 area 0 on FastEthernet0/0 from 10.0.0.2
*Mar  1 13:26:38.080: OSPF: Rcv hello from 1.1.1.1 area 0 from FastEthernet0/0 10.0.0.1
*Mar  1 13:26:38.080: OSPF: Neighbor change Event on interface FastEthernet0/0
*Mar  1 13:26:38.080: OSPF: DR/BDR election on FastEthernet0/0 
*Mar  1 13:26:38.080: OSPF: Elect BDR 1.1.1.1
*Mar  1 13:26:38.080: OSPF: Elect DR 22.22.22.22
*Mar  1 13:26:38.080:        DR: 22.22.22.22 (Id)   BDR: 1.1.1.1 (Id)
*Mar  1 13:26:38.080: OSPF: Neighbor change Event on interface FastEthernet0/0
*Mar  1 13:26:38.080: OSPF: DR/BDR election on FastEthernet0/0 
*Mar  1 13:26:38.080: OSPF: Elect BDR 1.1.1.1
*Mar  1 13:26:38.080: OSPF: Elect DR 22.22.22.22
*Mar  1 13:26:38.080:        DR: 22.22.22.22 (Id)   BDR: 1.1.1.1 (Id)
*Mar  1 13:26:38.080: OSPF: End of hello processing

R02’s OSPF neighbor.

R2#sh ip ospf neighbor 

Neighbor ID     Pri   State           Dead Time   Address         Interface
1.1.1.1           1   FULL/BDR        00:00:38    10.0.0.1        FastEthernet0/0

R01's OSPF neighbor.

R1#sh ip ospf neighbor
Neighbor ID     Pri   State           Dead Time   Address         Interface
22.22.22.22       1   FULL/DR         00:00:33    10.0.0.2        FastEthernet0/0
R1#

R03 comes back online. However, it’s not elected back as the DR. It only becomes a DR when current DR and BDR go down.

R3(config-if)#no shut
R3(config-if)#
*Mar  1 13:32:15.880: OSPF: Interface FastEthernet0/0 going Up
*Mar  1 13:32:15.916: OSPF: rcv. v:2 t:1 l:52 rid:22.22.22.22
      aid:0.0.0.0 chk:6823 aut:0 auk: from FastEthernet0/0
*Mar  1 13:32:15.920: OSPF: 2 Way Communication to 22.22.22.22 on FastEthernet0/0, state 2WAY
*Mar  1 13:32:15.920: OSPF: rcv. v:2 t:1 l:52 rid:1.1.1.1
      aid:0.0.0.0 chk:6823 aut:0 auk: from FastEthernet0/0
*Mar  1 13:32:15.920: OSPF: 2 Way Communication to 1.1.1.1 on FastEthernet0/0, state 2WAY
*Mar  1 13:32:15.920: OSPF: Backup seen Event before WAIT timer on FastEthernet0/0
*Mar  1 13:32:15.920: OSPF: DR/BDR election on FastEthernet0/0 
*Mar  1 13:32:15.920: OSPF: Elect BDR 1.1.1.1
*Mar  1 13:32:15.920: OSPF: Elect DR 22.22.22.22
*Mar  1 13:32:15.920:        DR: 22.22.22.22 (Id)   BDR: 1.1.1.1 (Id)
*Mar  1 13:32:15.920: OSPF: Send DBD to 1.1.1.1 on FastEthernet0/0 seq 0x1216 opt 0x52 flag 0x7 len 32
R3(config-if)#15.920: OSPF: Send DBD to 22.22.22.22 on FastEthernet0/0 seq 0x22D9 opt 0x52 flag 0x7 len 32
*Mar  1 13:32:16.380: OSPF: Build router LSA for area 0, router ID 33.33.33.33, seq 0x80000007
*Mar  1 13:32:16.848: OSPF: rcv. v:2 t:1 l:52 rid:1.1.1.1
      aid:0.0.0.0 chk:6823 aut:0 auk: from FastEthernet0/0
*Mar  1 13:32:17.872: %LINK-3-UPDOWN: Interface FastEthernet0/0, changed state to up
*Mar  1 13:32:18.872: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/0, changed state to up
*Mar  1 13:32:20.920: OSPF: Send DBD to 1.1.1.1 on FastEthernet0/0 seq 0x1216 opt 0x52 flag 0x7 len 32
*Mar  1 13:32:20.920: OSPF: Retransmitting DBD to 1.1.1.1 on FastEthernet0/0 [1]
*Mar  1 13:32:20.920: OSPF: Send DBD to 22.22.22.22 on FastEthernet0/0 seq 0x22D9 opt 0x52 flag 0x7 len 32
*Mar  1 13:32:20.924: OSPF: Retransmitting DBD to 22.22.22.22 on FastEthernet0/0 [1]
*Mar  1 13:32:20.960: OSPF: rcv. v:2 t:2 l:32 rid:1.1.1.1
      aid:0.0.0.0 chk:9B57 aut:0 auk: from FastEthernet0/0
*Mar  1 13:32:20.964: OSPF: Rcv DBD from 1.1.1.1 on FastEthernet0/0 seq 0x8A1 opt 0x52 flag 0x7 len 32  mtu 1500 state EXSTART
*Mar  1 13:32:20.964: OSPF: First DBD and we are not SLAVE
*Mar  1 13:32:20.972: OSPF: rcv. v:2 t:2 l:32 rid:22.22.22.22
      aid:0.0.0.0 chk:67CF aut:0 auk: from FastEthernet0/0
*Mar  1 13:32:20.972: OSPF: rcv. v:2 t:2 l:152 rid:1.1.1.1
      aid:0.0.0.0 chk:6E35 aut:0 auk: from FastEthernet0/0
*Mar  1 13:32:20.972: OSPF: Rcv DBD from 22.22.22.22 on FastEthernet0/0 seq 0x11FF opt 0x52 flag 0x7 len 32  mtu 1500 state EXSTART
*Mar  1 13:32:20.972: OSPF: First DBD and we are not SLAVE
*Mar  1 13:32:20.972: OSPF: Rcv DBD from 1.1.1.1 on FastEthernet0/0 seq 0x1216 opt 0x52 flag 0x2 len 152  mtu 1500 state EXSTART
*Mar  1 13:32:20.972: OSPF: NBR Negotiation Done. We are the MASTER
*Mar  1 13:32:20.972: OSPF: Send DBD to 1.1.1.1 on FastEthernet0/0 seq 0x1217 opt 0x52 flag 0x3 len 112
*Mar  1 13:32:20.980: OSPF: rcv. v:2 t:2 l:152 rid:22.22.22.22
      aid:0.0.0.0 chk:3349 aut:0 auk: from FastEthernet0/0
*Mar  1 13:32:20.980: OSPF: Rcv DBD from 22.22.22.22 on FastEthernet0/0 seq 0x22D9 opt 0x52 flag 0x2 len 152  mtu 1500 state EXSTART
*Mar  1 13:32:20.984: OSPF: NBR Negotiation Done. We are the MASTER
*Mar  1 13:32:20.984: OSPF: Send DBD to 22.22.22.22 on FastEthernet0/0 seq 0x22DA opt 0x52 flag 0x3 len 112
*Mar  1 13:32:20.992: OSPF: rcv. v:2 t:2 l:32 rid:1.1.1.1
      aid:0.0.0.0 chk:91E8 aut:0 auk: from FastEthernet0/0
*Mar  1 13:32:20.992: OSPF: Rcv DBD from 1.1.1.1 on FastEthernet0/0 seq 0x1217 opt 0x52 flag 0x0 len 32  mtu 1500 state EXCHANGE
*Mar  1 13:32:20.992: OSPF: Send DBD to 1.1.1.1 on FastEthernet0/0 seq 0x1218 opt 0x52 flag 0x1 len 32
*Mar  1 13:32:20.992: OSPF: Send LS REQ to 1.1.1.1 length 48 LSA count 4
*Mar  1 13:32:21.000: OSPF: rcv. v:2 t:2 l:32 rid:22.22.22.22
      aid:0.0.0.0 chk:56FB aut:0 auk: from FastEthernet0/0
*Mar  1 13:32:21.004: OSPF: Rcv DBD from 22.22.22.22 on FastEthernet0/0 seq 0x22DA opt 0x52 flag 0x0 len 32  mtu 1500 state EXCHANGE
*Mar  1 13:32:21.004: OSPF: Send DBD to 22.22.22.22 on FastEthernet0/0 seq 0x22DB opt 0x52 flag 0x1 len 32
*Mar  1 13:32:21.004: OSPF: Send LS REQ to 22.22.22.22 length 48 LSA count 4
*Mar  1 13:32:21.012: OSPF: rcv. v:2 t:3 l:36 rid:1.1.1.1
      aid:0.0.0.0 chk:7751 aut:0 auk: from FastEthernet0/0
*Mar  1 13:32:21.012: OSPF: Rcv LS REQ from 1.1.1.1 on FastEthernet0/0 length 36 LSA count 1
*Mar  1 13:32:21.012: OSPF: Send UPD to 10.0.0.1 on FastEthernet0/0 length 52 LSA count 1
*Mar  1 13:32:21.024: OSPF: rcv. v:2 t:2 l:32 rid:1.1.1.1
      aid:0.0.0.0 chk:91E7 aut:0 auk: from FastEthernet0/0
*Mar  1 13:32:21.024: OSPF: Rcv DBD from 1.1.1.1 on FastEthernet0/0 seq 0x1218 opt 0x52 flag 0x0 len 32  mtu 1500 state EXCHANGE
*Mar  1 13:32:21.024: OSPF: Exchange Done with 1.1.1.1 on FastEthernet0/0
*Mar  1 13:32:21.032: OSPF: rcv. v:2 t:3 l:36 rid:22.22.22.22
      aid:0.0.0.0 chk:4D27 aut:0 auk: from FastEthernet0/0
*Mar  1 13:32:21.032: OSPF: rcv. v:2 t:4 l:192 rid:1.1.1.1
      aid:0.0.0.0 chk:F228 aut:0 auk: from FastEthernet0/0
*Mar  1 13:32:21.032: OSPF: Rcv LS REQ from 22.22.22.22 on FastEthernet0/0 length 36 LSA count 1
*Mar  1 13:32:21.032: OSPF: Send UPD to 10.0.0.2 on FastEthernet0/0 length 52 LSA count 1
*Mar  1 13:32:21.032: OSPF: Rcv LS UPD from 1.1.1.1 on FastEthernet0/0 length 192 LSA count 4
*Mar  1 13:32:21.036: OSPF: We are not DR to build Net Lsa for interface FastEthernet0/0
*Mar  1 13:32:21.036: OSPF: Build network LSA for FastEthernet0/0, router ID 33.33.33.33
*Mar  1 13:32:21.036: OSPF: Build network LSA for FastEthernet0/0, router ID 33.33.33.33
*Mar  1 13:32:21.036: OSPF: Synchronized with 1.1.1.1 on FastEthernet0/0, state FULL
*Mar  1 13:32:21.036: %OSPF-5-ADJCHG: Process 1, Nbr 1.1.1.1 on FastEthernet0/0 from LOADING to FULL, Loading Done
*Mar  1 13:32:21.044: OSPF: rcv. v:2 t:2 l:32 rid:22.22.22.22
      aid:0.0.0.0 chk:56FA aut:0 auk: from FastEthernet0/0
*Mar  1 13:32:21.044: OSPF: Rcv DBD from 22.22.22.22 on FastEthernet0/0 seq 0x22DB opt 0x52 flag 0x0 len 32  mtu 1500 state EXCHANGE
*Mar  1 13:32:21.044: OSPF: Exchange Done with 22.22.22.22 on FastEthernet0/0
*Mar  1 13:32:21.044: OSPF: Synchronized with 22.22.22.22 on FastEthernet0/0, state FULL
*Mar  1 13:32:21.044: %OSPF-5-ADJCHG: Process 1, Nbr 22.22.22.22 on FastEthernet0/0 from LOADING to FULL, Loading Done

R03’s OSPF neighbor.

R3#sh ip ospf neighbor 

Neighbor ID     Pri   State           Dead Time   Address         Interface
1.1.1.1           1   FULL/BDR        00:00:35    10.0.0.1        FastEthernet0/0
22.22.22.22       1   FULL/DR         00:00:34    10.0.0.2        FastEthernet0/0

R02 goes down by shutting down F0/0 interface. R01 claims the new DR even though R03 has the highest Router ID.

*Mar  1 13:36:38.156: OSPF: rcv. v:2 t:1 l:52 rid:22.22.22.22
      aid:0.0.0.0 chk:6823 aut:0 auk: from FastEthernet0/0
*Mar  1 13:36:38.156: OSPF: Rcv hello from 22.22.22.22 area 0 from FastEthernet0/0 10.0.0.2
*Mar  1 13:36:38.160: OSPF: End of hello processing
*Mar  1 13:36:38.408: OSPF: rcv. v:2 t:1 l:52 rid:33.33.33.33
      aid:0.0.0.0 chk:6823 aut:0 auk: from FastEthernet0/0
*Mar  1 13:36:38.408: OSPF: Rcv hello from 33.33.33.33 area 0 from FastEthernet0/0 10.0.0.3
*Mar  1 13:36:38.408: OS
R1#PF: End of hello processing
*Mar  1 13:36:39.388: OSPF: Send hello to 224.0.0.5 area 0 on FastEthernet0/0 from 10.0.0.1
*Mar  1 13:36:48.416: OSPF: rcv. v:2 t:1 l:52 rid:33.33.33.33
      aid:0.0.0.0 chk:6823 aut:0 auk: from FastEthernet0/0
*Mar  1 13:36:48.416: OSPF: Rcv hello from 33.33.33.33 area 0 from FastEthernet0/0 10.0.0.3
*Mar  1 13:36:48.416: OSPF: End of hello processing
*Mar  1 13:36:49.388: OSPF: Send hello to 224.0.0.5 area 0 on FastEthernet0/0 from 10.0.0.1
*Mar  1 13:36:58.428: OSPF: rcv. v:2 t:1 l:52 rid:33.33.33.33
      aid:0.0.0.0 chk:6823 aut:0 auk: from FastEthernet0/0
*Mar  1 13:36:58.428: OSPF: Rcv hello from 33.33.33.33 area 0 from FastEthernet0/0 10.0.0.3
*Mar  1 13:36:58.428: OSPF: End of hello processing
*Mar  1 13:36:59.388: OSPF: Send hello to 224.0.0.5 area 0 on FastEthernet0/0 from 10.0.0.1
*Mar  1 13:37:08.408: OSPF: rcv. v:2 t:1 l:52 rid:33.33.33.33
      aid:0.0.0.0 chk:6823 aut:0 auk: from FastEthernet0/0
*Mar  1 13:37:08.408: OSPF: Rcv hello from 33.33.33.33 area 0 from FastEthernet0/0 10.0.0.3
*Mar  1 13:37:08.412: OSPF: End of hello processing
*Mar  1 13:37:09.388: OSPF: Send hello to 224.0.0.5 area 0 on FastEthernet0/0 from 10.0.0.1
*Mar  1 13:37:18.160: OSPF: 22.22.22.22 address 10.0.0.2 on FastEthernet0/0 is dead
*Mar  1 13:37:18.160: OSPF: 22.22.22.22 address 10.0.0.2 on FastEthernet0/0 is dead, state DOWN
*Mar  1 13:37:18.160: %OSPF-5-ADJCHG: Process 1, Nbr 22.22.22.22 on FastEthernet0/0 from FULL to DOWN, Neighbor Down: Dead timer expired
*Mar  1 13:37:18.164: OSPF: Neighbor change Event on interface FastEthernet0/0
*Mar  1 13:37:18.164: OSPF: DR/BDR election on FastEthernet0/0 
*Mar  1 13:37:18.164: OSPF: Elect BDR 1.1.1.
*Mar  1 13:37:18.164: OSPF: Elect DR 1.1.1.1
*Mar  1 13:37:18.164: OSPF: Elect BDR 33.33.33.33
*Mar  1 13:37:18.164: OSPF: Elect DR 1.1.1.1
*Mar  1 13:37:18.164:        DR: 1.1.1.1 (Id)   BDR: 33.33.33.33 (Id)
*Mar  1 13:37:18.164: OSPF: Remember old DR 22.22.22.22 (id)
*Mar  1 13:37:18.400: OSPF: rcv. v:2 t:1 l:48 rid:33.33.33.33
      aid:0.0.0.0 chk:9454 aut:0 auk: from FastEthernet0/0
*Mar  1 13:37:18.400: OSPF: Rcv hello from 33.33.33.33 area 0 from FastEthernet0/0 10.0.0.3
*Mar  1 13:37:18
R1#sh ip ospf ne.400: OSPF: Neighbor change Event on interface FastEthernet0/0
*Mar  1 13:37:18.404: OSPF: DR/BDR election on FastEthernet0/0 
*Mar  1 13:37:18.404: OSPF: Elect BDR 33.33.33.33
*Mar  1 13:37:18.404: OSPF: Elect DR 1.1.1.1
*Mar  1 13:37:18.404:        DR: 1.1.1.1 (Id)   BDR: 33.33.33.33 (Id)
*Mar  1 13:37:18.404: OSPF: End of hello processing
*Mar  1 13:37:18.656: OSPF: rcv. v:2 t:4 l:76 rid:33.33.33.33
      aid:0.0.0.0 chk:6DB9 aut:0 auk: from FastEthernet0/0
*Mar  1 13:37:18.656: OSPF: Rcv LS UPD
R1#sh ip ospf ne from 33.33.33.33 on FastEthernet0/0 length 76 LSA count 1
*Mar  1 13:37:18.664: OSPF: Build router LSA for area 0, router ID 1.1.1.1, seq 0x80000007
*Mar  1 13:37:18.664: OSPF: Build network LSA for FastEthernet0/0, router ID 1.1.1.1
*Mar  1 13:37:18.664: OSPF: Build network LSA for FastEthernet0/0, router ID 1.1.1.1
*Mar  1 13:37:19.388: OSPF: Send hello to 224.0.0.5 area 0 on FastEthernet0/0 from 10.0.0.1
*Mar  1 13:37:21.236: OSPF: rcv. v:2 t:5 l:64 rid:33.33.33.33
      aid:0.0.0.0 chk:66A8 aut:0 auk: from FastEthernet0/0
*Mar  1 13:37:28.412: OSPF: rcv. v:2 t:1 l:48 rid:33.33.33.33
      aid:0.0.0.0 chk:9452 aut:0 auk: from FastEthernet0/0
*Mar  1 13:37:28.416: OSPF: Rcv hello from 33.33.33.33 area 0 from FastEthernet0/0 10.0.0.3
*Mar  1 13:37:28.416: OSPF: Neighbor change Event on interface FastEthernet0/0
*Mar  1 13:37:28.416: OSPF: DR/BDR election on FastEthernet0/0 
*Mar  1 13:37:28.416: OSPF: Elect BDR 33.33.33.33
*Mar  1 13:37:28.416: OSPF: Elect DR 1.1.1.1
*Mar  1 13:37:28.416:        DR: 1.1.1.1 (Id)   BDR: 33.33.33.33 (Id)
*Mar  1 13:37:28.420: OSPF: End of hello processing
*Mar  1 13:37:29.388: OSPF: Send hello to 224.0.0.5 area 0 on FastEthernet0/0 from 10.0.0.1

The command “show IP ospf interface” shows all the interface running OSPF. The output displays important information like network type, hello intervals including dead, wait and retransmits and DR/BDR.

R1#sh ip ospf interface fastEthernet 0/0
FastEthernet0/0 is up, line protocol is up 
  Internet Address 10.0.0.1/24, Area 0 
  Process ID 1, Router ID 1.1.1.1, Network Type BROADCAST, Cost: 10
  Transmit Delay is 1 sec, State DROTHER, Priority 1 
  Designated Router (ID) 33.33.33.33, Interface address 10.0.0.3
  Backup Designated router (ID) 22.22.22.22, Interface address 10.0.0.2
  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 1/1, flood queue length 0
  Next 0x0(0)/0x0(0)
  Last flood scan length is 0, maximum is 2
  Last flood scan time is 0 msec, maximum is 4 msec
  Neighbor Count is 2, Adjacent neighbor count is 2 
    Adjacent with neighbor 22.22.22.22  (Backup Designated Router)
    Adjacent with neighbor 33.33.33.33  (Designated Router)
  Suppress hello for 0 neighbor(s)

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