[BSCI]配置OSPF DR选举过程

R1配置

r1(config)#int f0/0
r1(config-if)#ip ad 192.168.0.1 255.255.255.0
r1(config-if)#no sh
r1(config-if)#exi

R2配置

r2(config)#int f0/0
r2(config-if)#ip ad 192.168.0.2 255.255.255.0
r2(config-if)#no sh
r2(config-if)#exi

R3配置

r3(config)#int f0/0
r3(config-if)#ip ad 192.168.0.3 255.255.255.0
r3(config-if)#no sh

在R1上配置OSPF路由
r1(config)#router os 100
r1(config-router)#net 192.168.0.1 0.0.0.0 a 0
r1(config-router)#end

r1#debug ip os adj
OSPF adjacency events debugging is on
*Jul 23 13:14:43.103: OSPF: end of Wait on interface FastEthernet0/0
*Jul 23 13:14:43.103: OSPF: DR/BDR election on FastEthernet0/0
*Jul 23 13:14:43.103: OSPF: Elect BDR 192.168.0.1
*Jul 23 13:14:43.103: OSPF: Elect DR 192.168.0.1
*Jul 23 13:14:43.103: OSPF: Elect BDR 0.0.0.0
*Jul 23 13:14:43.103: OSPF: Elect DR 192.168.0.1
*Jul 23 13:14:43.103:        DR: 192.168.0.1 (Id)   BDR: none
*Jul 23 13:14:43.607: OSPF: No full nbrs to build Net Lsa for interface FastEthernet0/0
r1#u all
All possible debugging has been turned off         因为3台路由器只有R1配置了OSPF，所以DR为它自己。

开启R2 OSPF路由  比R1上开启debug消息

r2(config)#router os 100
r2(config-router)#net 192.168.0.2 0.0.0.0 a 0

r1#deb ip os ev
OSPF events debugging is on
r1#
*Jul 23 13:22:33.107: OSPF: Send hello to 224.0.0.5 area 0 on FastEthernet0/0 from 192.168.0.1
r1#
*Jul 23 13:22:43.107: OSPF: Send hello to 224.0.0.5 area 0 on FastEthernet0/0 from 192.168.0.1
r1#
*Jul 23 13:22:53.107: OSPF: Send hello to 224.0.0.5 area 0 on FastEthernet0/0 from 192.168.0.1
r1#
*Jul 23 13:22:59.039: OSPF: Rcv hello from 192.168.0.2 area 0 from FastEthernet0/0 192.168.0.2
*Jul 23 13:22:59.039: OSPF: Send immediate hello to nbr 192.168.0.2, src address 192.168.0.2, on FastEthernet0/0
*Jul 23 13:22:59.039: OSPF: Send hello to 192.168.0.2 area 0 on FastEthernet0/0 from 192.168.0.1
*Jul 23 13:22:59.043: OSPF: End of hello processing
r1#
*Jul 23 13:23:03.107: OSPF: Send hello to 224.0.0.5 area 0 on FastEthernet0/0 from 192.168.0.1
*Jul 23 13:23:03.163: OSPF: Rcv hello from 192.168.0.2 area 0 from FastEthernet0/0 192.168.0.2
*Jul 23 13:23:03.163: OSPF: 2 Way Communication to 192.168.0.2 on FastEthernet0/0, state 2WAY             收到hello，开始2way阶段
*Jul 23 13:23:03.163: OSPF: Neighbor change Event on interface FastEthernet0/0
*Jul 23 13:23:03.163: OSPF: DR/BDR election on FastEthernet0/0
*Jul 23 13:23:03.167: OSPF: Elect BDR 192.168.0.2
*Jul 23 13:23:03.167: OSPF: Elect DR 192.168.0.1
*Jul 23 13:23:03.167:        DR: 192.168.0.1 (Id)   BDR: 192.168.0.2 (Id)
*Jul 23 13:23:03.167: OSPF: Send DBD to 192.168.0.2 on FastEthernet0/0 seq 0x9FB opt 0x52 flag 0x7 len 32
*Jul 23 13:23:03.167: OSPF: Neighbor change Event on interface FastEthernet0/0
*Jul 23 13:23:03.171: OSPF: DR/BDR election on FastEthernet0/0
*Jul 23 13:23:03.171: OSPF: Elect BDR 192.168.0.2
*Jul 23 13:23:03.171: OSPF: Elect DR 192.168.0.1
*Jul 23 13:23:03.171:        DR: 192
r1#.168.0.1 (Id)   BDR: 192.168.0.2 (Id)
*Jul 23 13:23:03.171: OSPF: Neighbor change Event on interface FastEthernet0/0
*Jul 23 13:23:03.171: OSPF: DR/BDR election on FastEthernet0/0
*Jul 23 13:23:03.171: OSPF: Elect BDR 192.168.0.2
*Jul 23 13:23:03.175: OSPF: Elect DR 192.168.0.1
*Jul 23 13:23:03.175:        DR: 192.168.0.1 (Id)   BDR: 192.168.0.2 (Id)
*Jul 23 13:23:03.175: OSPF: End of hello processing
*Jul 23 13:23:03.175: OSPF: Rcv DBD from 192.168.0.2 on FastEthernet0/0 seq 0x1182 opt 0x52 flag 0x7 len 32  mtu 1500 state EXSTART            EXSTART阶段
*Jul 23 13:23:03.175: OSPF: NBR Negotiation Done. We are the SLAVE
*Jul 23 13:23:03.175: OSPF: Send DBD to 192.168.0.2 on FastEthernet0/0 seq 0x1182 opt 0x52 flag 0x2 len 52
*Jul 23 13:23:03.255: OSPF: Rcv DBD from 192.168.0.2 on FastEthernet0/0 seq 0x1183 opt 0x52 flag 0x3 len 52  mtu 1500 state EXCHANGE           EXCHANGE阶段    
*Jul 23 13:23:03.255: OSPF: Send DBD to 192.168.0.2 on FastEthernet0/0 seq 0x1183 opt 0x52 flag 0x0 len 32
*Jul 23 13:23:03.271: OSPF: Rcv DBD
r1# from 192.168.0.2 on FastEthernet0/0 seq 0x1184 opt 0x52 flag 0x1 len 32  mtu 1500 state EXCHANGE
*Jul 23 13:23:03.271: OSPF: Exchange Done with 192.168.0.2 on FastEthernet0/0
*Jul 23 13:23:03.271: OSPF: Send LS REQ to 192.168.0.2 length 12 LSA count 1
*Jul 23 13:23:03.275: OSPF: Send DBD to 192.168.0.2 on FastEthernet0/0 seq 0x1184 opt 0x52 flag 0x0 len 32
*Jul 23 13:23:03.303: OSPF: Rcv LS REQ from 192.168.0.2 on FastEthernet0/0 length 36 LSA count 1
*Jul 23 13:23:03.303: OSPF: Send UPD to 192.168.0.2 on FastEthernet0/0 length 40 LSA count 1
*Jul 23 13:23:03.319: OSPF: Rcv LS UPD from 192.168.0.2 on FastEthernet0/0 length 64 LSA count 1
*Jul 23 13:23:03.319: OSPF: Synchronized with 192.168.0.2 on FastEthernet0/0, state FULL
*Jul 23 13:23:03.319: %OSPF-5-ADJCHG: Process 100, Nbr 192.168.0.2 on FastEthernet0/0 from LOADING to FULL, Loading Done
r1#
*Jul 23 13:23:05.459: OSPF: Rcv LS UPD from 192.168.0.2 on FastEthernet0/0 length 64 LSA count 1
r1#
*Jul 23 13:23:08.955: OSPF: Rcv hello from 192.168.0.2 area 0 from FastEthernet0/0 192.168.0.2
*Jul 23 13:23:08.955: OSPF: End of hello processing
r1#
*Jul 23 13:23:13.107: OSPF: Send hello to 224.0.0.5 area 0 on FastEthernet0/0 from 192.168.0.1
r1#
*Jul 23 13:23:18.971: OSPF: Rcv hello from 192.168.0.2 area 0 from FastEthernet0/0 192.168.0.2
*Jul 23 13:23:18.971: OSPF: End of hello processing
r1#
*Jul 23 13:23:23.107: OSPF: Send hello to 224.0.0.5 area 0 on FastEthernet0/0 from 192.168.0.1
r1#
*Jul 23 13:23:28.971: OSPF: Rcv hello from 192.168.0.2 area 0 from FastEthernet0/0 192.168.0.2
*Jul 23 13:23:28.971: OSPF: End of hello processing
r1#
*Jul 23 13:23:33.107: OSPF: Send hello to 224.0.0.5 area 0 on FastEthernet0/0 from 192.168.0.1
r1#
*Jul 23 13:23:38.987: OSPF: Rcv hello from 192.168.0.2 area 0 from FastEthernet0/0 192.168.0.2
*Jul 23 13:23:38.987: OSPF: End of hello processing
r1#
*Jul 23 13:23:43.107: OSPF: Send hello to 224.0.0.5 area 0 on FastEthernet0/0 from 192.168.0.1
r1#
*Jul 23 13:23:48.971: OSPF: Rcv hello from 192.168.0.2 area 0 from FastEthernet0/0 192.168.0.2
*Jul 23 13:23:48.971: OSPF: End of hello processing
r1#
*Jul 23 13:23:53.107: OSPF: Send hello to 224.0.0.5 area 0 on FastEthernet0/0 from 192.168.0.1
r1#
*Jul 23 13:23:58.971: OSPF: Rcv hello from 192.168.0.2 area 0 from FastEthernet0/0 192.168.0.2
*Jul 23 13:23:58.971: OSPF: End of hello processing
r1#
*Jul 23 13:24:03.107: OSPF: Send hello to 224.0.0.5 area 0 on FastEthernet0/0 from 192.168.0.1
r1#
*Jul 23 13:24:08.971: OSPF: Rcv hello from 192.168.0.2 area 0 from FastEthernet0/0 192.168.0.2
*Jul 23 13:24:08.971: OSPF: End of hello processing
r1#
*Jul 23 13:24:13.107: OSPF: Send hello to 224.0.0.5 area 0 on FastEthernet0/0 from 192.168.0.1
r1#
*Jul 23 13:24:18.971: OSPF: Rcv hello from 192.168.0.2 area 0 from FastEthernet0/0 192.168.0.2
*Jul 23 13:24:18.971: OSPF: End of hello processing
r1#
*Jul 23 13:24:23.107: OSPF: Send hello to 224.0.0.5 area 0 on FastEthernet0/0 from 192.168.0.1
r1#
*Jul 23 13:24:28.987: OSPF: Rcv hello from 192.168.0.2 area 0 from FastEthernet0/0 192.168.0.2
*Jul 23 13:24:28.987: OSPF: End of hello processing
r1#u all
All possible debugging has been turned off
r1#
*Jul 23 13:24:33.107: OSPF: Send hello to 224.0.0.5 area 0 on FastEthernet0/0 from 192.168.0.1

R1上重新启动OSPF进程
r1#clear ip os pr
Reset ALL OSPF processes? [no]: y
r1#
*Jul 23 13:26:03.859: %OSPF-5-ADJCHG: Process 100, Nbr 192.168.0.2 on FastEthernet0/0 from FULL to DOWN, Neighbor Down: Interface down or detached
*Jul 23 13:26:04.103: %OSPF-5-ADJCHG: Process 100, Nbr 192.168.0.2 on FastEthernet0/0 from LOADING to FULL, Loading Done
r1#sh ip os nei

Neighbor ID     Pri   State           Dead Time   Address         Interface
192.168.0.2       1   FULL/DR         00:00:33    192.168.0.2     FastEthernet0/0          重启后R2成为了DR

R3配置OSPF路由

r3(config)#router os 100
r3(config-router)#net 192.168.0.3 0.0.0.0 a 0

在R1上SHOW一下OSPF邻居信息
r1#sh ip os nei

Neighbor ID     Pri   State           Dead Time   Address         Interface
192.168.0.2       1   FULL/DR         00:00:39    192.168.0.2     FastEthernet0/0
192.168.0.3       0   FULL/DROTHER    00:00:39    192.168.0.3     FastEthernet0/0