CCNP-5 OSPF试验1

试验拓扑：

试验要求：模拟在广播环境下， OSPF 的配置与调试。

试验目的：掌握 OSPF 的基本配置，并且能够分析得到 OSPF 在广播环境下邻居发现过程， DR/BDR 选举过程，定时器的时间间隔。

实验配置：

R1 ：

R1(config)#int f0/0

R1(config-if)#ip add 199.99.1.1 255.255.255.0

R1(config-if)#no shu

R1(config-if)#exit

R1(config)#int loop0

R1(config-if)#ip add  1.1.1 .1 255.255.255.0

R1(config-if)#ip ospf network point-to-point

R1(config-if)#exit

R1(config)#router ospf 100

R1(config-router)#router-id  1.1.1 .1

R1(config-router)#network 199.99.1.0  0.0.0 .255 a 0

 

R2 ：

R2(config)#int f0/0

R2(config-if)#ip add 199.99.1.2 255.255.255.0

R2(config-if)#no shu

R2(config-if)#exit

R2(config)#int loop0

R2(config-if)#ip add  2.2.2 .2 255.255.255.0

R2(config-if)#ip ospf network point-to-point

R2(config-if)#exit

R2(config)#router ospf 100

R2(config-router)#router-id  2.2.2 .2 

R2(config-router)#network 199.99.1.0  0.0.0 .255 a 0

 

R3 ：

R3(config)#int f0/0

R3(config-if)#ip add 199.99.1.3 255.255.255.0

R3(config-if)#no shu

R3(config-if)#exit

R3(config)#int loop0

R3(config-if)#ip add  3.3.3 .3 255.255.255.0

R3(config-if)#ip ospf network point-to-point

R3(config-if)#exit

R3(config)#router ospf 100

R3(config-router)#router-id  3.3.3 .3

R3(config-router)#network 199.99.1.0  0.0.0 .255 area 0

配置完成后，使用 show ip ospf interface 命令查看端口类型：

R1#show ip ospf interface f0/0

FastEthernet0/0 is up, line protocol is up

  Internet Address 199.99.1.1/24, Area 0

  Process ID 100, Router ID  1.1.1 .1, Network Type BROADCAST, Cost: 1

  Transmit Delay is 1 sec, State DROTHER, Priority 1

  Designated Router (ID)  3.3.3 .3, Interface address 199.99.1.3

  Backup Designated router (ID)  2.2.2 .2, Interface address 199.99.1.2

  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 1/1, flood queue length 0

  Next 0x0(0)/0x0(0)

  Last flood scan length is 1, maximum is 1

  Last flood scan time is 0 msec, maximum is 0 msec

  Neighbor Count is 2, Adjacent neighbor count is 2

    Adjacent with neighbor  2.2.2 .2  (Backup Designated Router)

    Adjacent with neighbor  3.3.3 .3  (Designated Router)

  Suppress hello for 0 neighbor(s)

 

R2#show ip ospf interface f0/0

FastEthernet0/0 is up, line protocol is up

  Internet Address 199.99.1.2/24, Area 0

  Process ID 100, Router ID  2.2.2 .2, Network Type BROADCAST, Cost: 1

  Transmit Delay is 1 sec, State BDR, Priority 1

  Designated Router (ID)  3.3.3 .3, Interface address 199.99.1.3

  Backup Designated router (ID)  2.2.2 .2, Interface address 199.99.1.2

  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 1/1, flood queue length 0

  Next 0x0(0)/0x0(0)

  Last flood scan length is 0, maximum is 1

  Last flood scan time is 0 msec, maximum is 0 msec

  Neighbor Count is 2, Adjacent neighbor count is 2

    Adjacent with neighbor  1.1.1 .1

    Adjacent with neighbor  3.3.3 .3  (Designated Router)

  Suppress hello for 0 neighbor(s)

 

R3#show ip ospf interface f0/0

FastEthernet0/0 is up, line protocol is up

  Internet Address 199.99.1.3/24, Area 0

  Process ID 100, Router ID  3.3.3 .3, Network Type BROADCAST, Cost: 1

  Transmit Delay is 1 sec,  State DR , Priority 1

  Designated Router (ID)  3.3.3 .3, Interface address 199.99.1.3

  Backup Designated router (ID)  2.2.2 .2, Interface address 199.99.1.2

  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 1/1, flood queue length 0

  Next 0x0(0)/0x0(0)

  Last flood scan length is 1, maximum is 1

  Last flood scan time is 0 msec, maximum is 0 msec

  Neighbor Count is 2, Adjacent neighbor count is 2

    Adjacent with neighbor  1.1.1 .1

    Adjacent with neighbor  2.2.2 .2  (Backup Designated Router)

  Suppress hello for 0 neighbor(s)

不仅可以看到网络类型是 BROADCAST ，还可以知道端口属于哪个 AREA ， ROUTER ID 是多少，优先级都是默认值 1DR,BDR 是谁， HELLO/DEAD/WAIT 计时器为多少等等。

 

使用 show ip ospf neiighbore 命令查看 OSPF 邻居表：

R1#show ip ospf neighbor 

 

Neighbor ID     Pri   State           Dead Time   Address         Interface

2.2.2 .2           1   FULL/BDR        00:00:32    199.99.1.2      FastEthernet0/0

3.3.3 .3           1   FULL/DR         00:00:36    199.99.1.3      FastEthernet0/0

 

R2#show ip ospf neighbor

 

Neighbor ID     Pri   State           Dead Time   Address         Interface

1.1.1 .1           1   FULL/DROTHER    00:00:32    199.99.1.1      FastEthernet0/0

3.3.3 .3           1   FULL/DR         00:00:35    199.99.1.3      FastEthernet0/0

 

R3#show ip ospf neighbor

 

Neighbor ID     Pri   State           Dead Time   Address         Interface

1.1.1 .1           1   FULL/DROTHER    00:00:36    199.99.1.1      FastEthernet0/0

2.2.2 .2           1   FULL/BDR        00:00:35    199.99.1.2      FastEthernet0/0

 

通过上面的输出可以知道 R3 是 DR ， R2 是 BDR ， R1 为 DROther ，这是因为 R3 的 router-id 最大， R2 的次之， R1 最小。再使用 show ip ospf database 查看都有哪些 LSA 类型：

R1#show ip ospf database

 

            OSPF Router with ID ( 1.1.1 .1) (Process ID 100)

 

                Router Link States (Area 0)

 

Link ID         ADV Router      Age         Seq#       Checksum Link count

1.1.1 .1          1.1.1 .1         353         0x80000002 0x00AF1E 1

2.2.2 .2          2.2.2 .2         354         0x80000002 0x007153 1

3.3.3 .3          3.3.3 .3         354         0x80000002 0x003388 1

 

                Net Link States (Area 0)

 

Link ID         ADV Router      Age         Seq#       Checksum

199.99.1.3       3.3.3 .3         354         0x80000001 0x 00736F

 

R2#show ip ospf database

 

            OSPF Router with ID ( 2.2.2 .2) (Process ID 100)

 

                Router Link States (Area 0)

 

Link ID         ADV Router      Age         Seq#       Checksum Link count

1.1.1 .1          1.1.1 .1         371         0x80000002 0x00AF1E 1

2.2.2 .2          2.2.2 .2         370         0x80000002 0x007153 1

3.3.3 .3          3.3.3 .3         371         0x80000002 0x003388 1

 

                Net Link States (Area 0)

 

Link ID         ADV Router      Age         Seq#       Checksum

199.99.1.3       3.3.3 .3         371         0x80000001 0x 00736F

 

R3#show ip ospf database

 

            OSPF Router with ID ( 3.3.3 .3) (Process ID 100)

 

                Router Link States (Area 0)

 

Link ID         ADV Router      Age         Seq#       Checksum Link count

1.1.1 .1          1.1.1 .1         379         0x80000002 0x00AF1E 1

2.2.2 .2          2.2.2 .2         379         0x80000002 0x007153 1

3.3.3 .3          3.3.3 .3         378         0x80000002 0x003388 1

 

                Net Link States (Area 0)

 

Link ID         ADV Router      Age         Seq#       Checksum

199.99.1.3       3.3.3 .3         378         0x80000001 0x 00736F

可以看到只有 1 类和 2 类 LSA 。

然后我们抓取一下 R1 的 debug 信息看看：

R1#debug ip ospf adj

OSPF adjacency events debugging is on

R1#

R1#clear ip ospf p

R1#clear ip ospf process

Reset ALL OSPF processes? [no]: y

R1#

*Mar  1 00:13:57.483: OSPF: Interface FastEthernet0/0 going Down

*Mar  1 00:13:57.483: OSPF:  1.1.1 .1 address 199.99.1.1 on FastEthernet0/0 is dead, state DOWN

*Mar  1 00:13:57.483: OSPF: Neighbor change Event on interface FastEthernet0/0

*Mar  1 00:13:57.483: OSPF: DR/BDR election on FastEthernet0/0

*Mar  1 00:13:57.487: OSPF: Elect BDR  2.2.2 .2

*Mar  1 00:13:57.487: OSPF: Elect DR  3.3.3 .3

*Mar  1 00:13:57.487:        DR:  3.3.3 .3 (Id)   BDR: 2.2.2.2 (Id)

*Mar  1 00:13:57.487: OSPF:  2.2.2 .2 address 199.99.1.2 on FastEthernet0/0 is dead, state DOWN

*Mar  1 00:13:57.487: %OSPF-5-ADJCHG: Process 100, Nbr  2.2.2 .2 on FastEthernet0/0 from FULL to DOWN, Neighbor Down: Interface down or detached

*Mar  1 00:13:57.491: OSPF: Neighbor change Event on interface FastEthernet0/0

*Mar  1 00:13:57.491: OSPF: DR/BDR election on FastEthernet0/0

*Mar  1 00:13:57.491: OSPF: Elect BDR  0.0.0 .0

*Mar  1 00:13:57.491: OSPF: Elect DR  3.3.3 .3

*Mar  1 00:13:57.495:        DR:  3.3.3 .3 (Id)   BDR: none

*Mar  1 00:13:57.495: OSPF:  3.3.3 .3 address 199.99.1.3 on FastEthernet0/0 is dead, state DOWN

*Mar  1 00:13:57.495: %OSPF-5-ADJCHG: Process 100, Nbr  3.3.3 .3 on FastEthernet0/0 from FULL to DOWN, Neighbor Down: Interface down or detached

*Mar  1 00:13:57.499: OSPF: Neighbor change Event on interface FastEthernet0/0

*Mar  1 00:13:57.499: OSPF: DR/BDR election on FastEthernet0/0

*Mar  1 00:13:57.499: OSPF: Elect BDR  0.0.0 .0

*Mar  1 00:13:57.499: OSPF: Elect DR  0.0.0 .0

*Mar  1 00:13:57.499:        DR: none    BDR: none

*Mar  1 00:13:57.503: OSPF: Remember old DR  3.3.3 .3 (id)

*Mar  1 00:13:57.587: OSPF: Interface FastEthernet0/0 going Up

*Mar  1 00:13:57.639: OSPF: 2 Way Communication to  2.2.2 .2 on FastEthernet0/0, state 2WAY \\与R2 建立邻居关系，形成 2 Way 。

*Mar  1 00:13:57.639: OSPF: Backup seen Event before WAIT timer on FastEthernet0/0

*Mar  1 00:13:57.639: OSPF: DR/BDR election on FastEthernet0/0  \\与R2比较，选取DR/BDR

*Mar  1 00:13:57.643: OSPF: Elect BDR  2.2.2 .2

*Mar  1 00:13:57.643: OSPF: Elect DR  2.2.2 .2

*Mar  1 00:13:57.643:        DR:  2.2.2 .2 (Id)   BDR: 2.2.2.2 (Id)

*Mar  1 00:13:57.643: OSPF: Send DBD to  2.2.2 .2 on FastEthernet0/0 seq 0x1522 opt 0x52 flag 0x7 len 32  \\ 发送数据库描述报文

*Mar  1 00:13:57.663: OSPF: 2 Way Communication to  3.3.3 .3 on FastEthernet0/0, state 2WAY \\与R3 建立邻居关系，形成 2 Way 。

*Mar  1 00:13:57.663: OSPF: Neighbor change Event on interface FastEthernet0/0

*Mar  1 00:13:57.663: OSPF: DR/BDR election on FastEthernet0/0 \\与R2和R3比较，选取DR/BDR

*Mar  1 00:13:57.667: OSPF: Elect BDR  2.2.2 .2

*Mar  1 00:13:57.667: OSPF: Elect DR  3.3.3 .3

*Mar  1 00:13:57.667:        DR:  3.3.3 .3 (Id)   BDR: 2.2.2.2 (Id)  \\DR 为 R3,BDR 为 R2

*Mar  1 00:13:57.667: OSPF: Send DBD to  3.3.3 .3 on FastEthernet0/0 seq 0x18AD opt 0x52 flag 0x7 len 32  \\ 发送数据库描述报文给 DR

*Mar  1 00:13:57.671: OSPF: Remember old DR  2.2.2 .2 (id)

*Mar  1 00:13:57.671: OSPF: Neighbor change Event on interface FastEthernet0/0

*Mar  1 00:13:57.671: OSPF: DR/BDR election on FastEthernet0/0

*Mar  1 00:13:57.671: OSPF: Elect BDR  2.2.2 .2

*Mar  1 00:13:57.671: OSPF: Elect DR  3.3.3 .3

*Mar  1 00:13:57.675:        DR:  3.3.3 .3 (Id)   BDR: 2.2.2.2 (Id)

*Mar  1 00:13:57.711: OSPF: Rcv DBD from  2.2.2 .2 on FastEthernet0/0 seq 0x11D0 opt 0x52 flag 0x7 len 32  mtu 1500 state EXSTART  \\收到R2 的数据库描述报文，转到 EXSTART 状态

*Mar  1 00:13:57.711: OSPF: NBR Negotiation Done. We are the SLAVE  \\MASTER/SLAVE 的选取，在此为 R2 为 MASTER ， R1 为 SLAVE 。

*Mar  1 00:13:57.715: OSPF: Send DBD to  2.2.2 .2 on FastEthernet0/0 seq 0x11D0 opt 0x52 flag 0x0 len 32

*Mar  1 00:13:57.759: OSPF: Rcv DBD from  3.3.3 .3 on FastEthernet0/0 seq 0x 78A  opt 0x52 flag 0x7 len 32  mtu 1500 state EXSTART \\收到R3 的数据库描述报文，转到 EXSTART 状态

*Mar  1 00:13:57.763: OSPF: NBR Negotiation Done. We are the SLAVE  \\MASTER/SLAVE 的选取，在此为 R3 为 MASTER ， R1 为 SLAVE 。

*Mar  1 00:13:57.763: OSPF: Send DBD to  3.3.3 .3 on FastEthernet0/0 seq 0x 78A  opt 0x52 flag 0x0 len 32

*Mar  1 00:13:57.767: OSPF: Rcv DBD from  2.2.2 .2 on FastEthernet0/0 seq 0x11D1 opt 0x52 flag 0x3 len 92  mtu 1500 state EXCHANGE  \\ 交换 DBD 报文，状态转为 EXCHANGE 。

*Mar  1 00:13:57.771: OSPF: Send DBD to  2.2.2 .2 on FastEthernet0/0 seq 0x11D1 opt 0x52 flag 0x0 len 32

*Mar  1 00:13:57.879: OSPF: Rcv DBD from  2.2.2 .2 on FastEthernet0/0 seq 0x11D2 opt 0x52 flag 0x1 len 32  mtu 1500 state EXCHANGE

*Mar  1 00:13:57.879: OSPF: Exchange Done with  2.2.2 .2 on FastEthernet0/0

*Mar  1 00:13:57.883: OSPF: Send LS REQ to  2.2.2 .2 length 36 LSA count 3  \\ 发送 LSR

*Mar  1 00:13:57.883: OSPF: Send DBD to  2.2.2 .2 on FastEthernet0/0 seq 0x11D2 opt 0x52 flag 0x0 len 32

*Mar  1 00:13:57.955: OSPF: Rcv DBD from  3.3.3 .3 on FastEthernet0/0 seq 0x78B opt 0x52 flag 0x3 len 92  mtu 1500 state EXCHANGE  \\ 交换 DBD 报文，状态转为 EXCHANGE 。

*Mar  1 00:13:57.955: OSPF: Send DBD to  3.3.3 .3 on FastEthernet0/0 seq 0x78B opt 0x52 flag 0x0 len 32

*Mar  1 00:13:57.987: OSPF: Reset old DR on FastEthernet0/0

*Mar  1 00:13:57.987: OSPF: Build router LSA for area 0, router ID  1.1.1 .1, seq 0x80000001

*Mar  1 00:13:57.995: OSPF: Rcv LS UPD from  2.2.2 .2 on FastEthernet0/0 length 136 LSA count 3  \\ 收到 LSU

*Mar  1 00:13:57.995: OSPF: Synchronized with  2.2.2 .2 on FastEthernet0/0, state FULL   *Mar  1 00:13:57.999: %OSPF-5-ADJCHG: Process 100, Nbr  2.2.2 .2 on FastEthernet0/0 from LOADING to FULL, Loading Done \\与R2 成为 FULL 状态。

*Mar  1 00:13:57.999: OSPF: Rcv DBD from  3.3.3 .3 on FastEthernet0/0 seq 0x 78C  opt 0x52 flag 0x1 len 32  mtu 1500 state EXCHANGE

*Mar  1 00:13:57.999: OSPF: Exchange Done with  3.3.3 .3 on FastEthernet0/0

*Mar  1 00:13:58.003: OSPF: Synchronized with  3.3.3 .3 on FastEthernet0/0, state FULL *Mar  1 00:13:58.003: %OSPF-5-ADJCHG: Process 100, Nbr  3.3.3 .3 on FastEthernet0/0 from LOADING to FULL, Loading Done \\与R3 成为 FULL 状态。

*Mar  1 00:13:58.003: OSPF: Send DBD to  3.3.3 .3 on FastEthernet0/0 seq 0x 78C  opt 0x52 flag 0x0 len 32

*Mar  1 00:13:58.083: OSPF: Rcv LS UPD from  3.3.3 .3 on FastEthernet0/0 length 60 LSA count 1

*Mar  1 00:14:02.583: OSPF: Rcv LS UPD from  2.2.2 .2 on FastEthernet0/0 length 64 LSA count 1

*Mar  1 00:14:02.783: OSPF: Rcv LS UPD from  3.3.3 .3 on FastEthernet0/0 length 64 LSA count 1

*Mar  1 00:14:02.855: OSPF: Rcv LS UPD from  2.2.2 .2 on FastEthernet0/0 length 64 LSA count 1

*Mar  1 00:14:02.859: OSPF: Rcv LS UPD from  3.3.3 .3 on FastEthernet0/0 length 64 LSA count 1

*Mar  1 00:14:03.135: OSPF: Rcv LS UPD from  3.3.3 .3 on FastEthernet0/0 length 64 LSA count 1

*Mar  1 00:14:03.499: OSPF: Build router LSA for area 0, router ID  1.1.1 .1, seq 0x80000003

*Mar  1 00:14:03.671: OSPF: Rcv LS UPD from  3.3.3 .3 on FastEthernet0/0 length 64 LSA count 1

红色标记 / 蓝色注释的部分比较重要，通过红色标记 / 蓝色注释的部分可以看到整个 OSPF 邻居建立和选取 DR/BDR 和交换 DBD 报文和 LSU/LSR/LSAck 报文，最终形成 FULL 状态的全部过程。

实验总结：通过这个简单的实验我们可以知道在广播环境下， OSPF 的邻居关系是自动建立的，并且需要有 DR/BDR 地选取，还可以看到几个特别计时器的设置， hello 间隔为 10 秒，死亡，等待时间为 hello 时间间隔的 4 倍 40 秒。