debug ip ospf adj (Initial)

Initial Configurations for OSPF Over Broadcast Media. Since the article is not presented for a rocket in networking but an expert-level networker, I ignored the detail configuration and just provide the sample network topology. And you should post your configuration on the routers before you issue the debug command in your lab. Here comes......

Router1#debug ip ospf adj
OSPF adjacency events debugging is on

*Mar 1 01:41:23.319: OSPF: Rcv DBD from 172.16.10.1 on Ethernet0 seq 0x1F6C opt 0x42 flag 0x7 len 32 mtu 1500 state INIT
*Mar 1 01:41:23.323: OSPF: 2 Way Communication to 172.16.10.1 on Ethernet0, state 2WAY
*Mar 1 01:41:23.327: OSPF: Neighbor change Event on interface Ethernet0
*Mar 1 01:41:23.327: OSPF: DR/BDR election on Ethernet0
*Mar 1 01:41:23.331: OSPF: Elect BDR 172.16.10.1
*Mar 1 01:41:23.331: OSPF: Elect DR 192.168.45.1
*Mar 1 01:41:23.335: DR: 192.168.45.1 (Id) BDR: 172.16.10.1 (Id)
*Mar 1 01:41:23.339: OSPF: Send DBD to 172.16.10.1 on Ethernet0 seq 0x2552 opt 0x42 flag 0x7 len 32
*Mar 1 01:41:23.343: OSPF: First DBD and we are not SLAVE
*Mar 1 01:41:23.359: OSPF: Rcv DBD from 172.16.10.1 on Ethernet0 seq 0x2552 opt 0x42 flag 0x2 len 52 mtu 1500 state EXSTART
*Mar 1 01:41:23.363: OSPF: NBR Negotiation Done. We are the MASTER
*Mar 1 01:41:23.367: OSPF: Send DBD to 172.16.10.1 on Ethernet0 seq 0x2553 opt
0x42 flag 0x3 len 72
*Mar 1 01:41:23.387: OSPF: Rcv DBD from 172.16.10.1 on Ethernet0 seq 0x2553 opt 0x42 flag 0x0 len 32 mtu 1500 state EXCHANGE
*Mar 1 01:41:23.391: OSPF: Send DBD to 172.16.10.1 on Ethernet0 seq 0x2554 opt 0x42 flag 0x1 len 32
*Mar 1 01:41:23.411: OSPF: Rcv DBD from 172.16.10.1 on Ethernet0 seq 0x2554 opt 0x42 flag 0x0 len 32 mtu 1500 state EXCHANGE
*Mar 1 01:41:23.415: OSPF: Exchange Done with 172.16.10.1 on Ethernet0
*Mar 1 01:41:23.419: OSPF: Synchronized with 172.16.10.1 on Ethernet0, state FULL
01:41:23: %OSPF-5-ADJCHG: Process 1, Nbr 172.16.10.1 on Ethernet0 from LOADING to FULL, Loading Done
*Mar 1 01:41:23.879: OSPF: Build router LSA for area 0, router ID 192.168.45.1,seq 0x80000004
*Mar 1 01:41:23.923: OSPF: Build network LSA for Ethernet0, router ID 192.168.45.1
*Mar 1 01:41:25.503: OSPF: Neighbor change Event on interface Ethernet0
*Mar 1 01:41:25.507: OSPF: DR/BDR election on Ethernet0
*Mar 1 01:41:25.507: OSPF: Elect BDR 172.16.10.1
*Mar 1 01:41:25.511: OSPF: Elect DR 192.168.45.1
*Mar 1 01:41:25.511: DR: 192.168.45.1 (Id) BDR: 172.16.10.1 (Id)

I'm explaining the opt field below and opt field is with responsibility for identifing the OSPF area type. It’s a number in hex, and after converted into bin, you will see what each bit is standing for:

Normal area:
OSPF: Send DBD to 141.108.97.1 on Serial0 seq 0xBC4 opt 0x2 flag 0x3 len 492
E bit is 1, Allow externals,
Option: 0x2(HEX) = 00000010(Bin)

Stub area:
OSPF: Send DBD to 141.108.97.1 on Serial0 seq 0x1866 opt 0x0 flag 0x3 len 372
E bit is 0, no external allowed,
Options: 0x0(HEX) = 00000000(Bin)

NSSA:
OSPF: Send DBD to 141.108.97.1 on Serial0 seq 0x118 opt 0x8 flag 0x3 len 372
N/P bit is on,
Options: 0x8(HEX) = 00001000(Bin)

DC:
OSPF: Send DBD to 141.108.97.1 on Serial0 seq 0x1A1E opt 0x20 flag 0x3 len 392
DC bit is negotiated,
Options: 0x20(HEX) = 00100000(Bin)

Then comes to the flag field, which presents the synchronization processing between Master and Slave routers.

Flag 0x7(HEX) -- 111(Bin) means:
I = 1(incremental)/0(Initial),
M = 1(More)/0(No more),
MS = 1(Master)/0(Slave)

Flag 0x6(HEX) -- 110(Bin) not possible
Flag 0x5(HEX) -- 101(Bin) not possible
Flag 0x4(HEX) -- 100(Bin) not possible
Flag 0x3(HEX) -- 011(Bin) means master has more data to send
Flag 0x2(HEX) -- 010(Bin) means slave has more data to send
Flag 0x1(HEX) -- 001(Bin) means master has no more data left to send
Flag 0x0(HEX) -- 000(Bin) means slave has no more data left to send

To verify the hello timer value, the debug ip ospf events command is used. This is the output of that command.

Router1#debug ip ospf events
OSPF events debugging is on
Router1#

*Mar 1 04:04:11.926: OSPF: Rcv hello from 172.16.10.1 area 0 from Ethernet0 10.10.10.2
*Mar 1 04:04:11.930: OSPF: End of hello processing
*Mar 1 04:04:21.926: OSPF: Rcv hello from 172.16.10.1 area 0 from Ethernet0 10.10.10.2
*Mar 1 04:04:21.930: OSPF: End of hello processing
*Mar 1 04:04:31.926: OSPF: Rcv hello from 172.16.10.1 area 0 from Ethernet0 10.10.10.2
*Mar 1 04:04:31.930: OSPF: End of hello processing
*Mar 1 04:04:41.926: OSPF: Rcv hello from 172.16.10.1 area 0 from Ethernet0 10.10.10.2
*Mar 1 04:04:41.930: OSPF: End of hello processing

From the output, you can see that the hello packet is exchanged every 10 seconds.