学会配置多区域的OSPF网络

学会配置多区域的OSPF网络

一、 实验目的

1、掌握配置多区域的OSPF网络的方法 2、理解DR与BDR的概念

3、掌握修改OSPF接口优先级的配置 4、掌握修改OSPF cost的配置

二、 实验拓扑

三、实验步骤

1、掌握配置多区域的OSPF网络的方法 1）基本配置及OSPF配置 AR1：

sy

system-view

Enter system view, return user view with Ctrl+Z.

[Huawei] info-center source DS channel 0 log state off trap state off [Huawei]sysname AR1

[AR1]user-interface console 0 [AR1-ui-console0]idle-timeout 0 0 [AR1-ui-console0]q [AR1]int gi0/0/0

[AR1-GigabitEthernet0/0/0]ip add 192.168.12.1 24 [AR1-GigabitEthernet0/0/0]int gi0/0/1

[AR1-GigabitEthernet0/0/1]ip add 192.168.13.1 24 [AR1-GigabitEthernet0/0/1]int loo0 [AR1-LoopBack0]ip add 1.1.1.1 32 [AR1-LoopBack0]q

OSPF配置：

[AR1]ospf 1 router-id 1.1.1.1 //启用ospf协议定义router-id号 [AR1-ospf-1]area 0 //先定义Area0域

[AR1-ospf-1-area-0.0.0.0]network 192.168.12.0 0.0.0.255 //配置区域0所包含的网段 [AR1-ospf-1-area-0.0.0.0]network 1.1.1.1 0.0.0.0 //配置区域0所包含的网段 [AR1-ospf-1-area-0.0.0.0]area 1 //定义area1域 [AR1-ospf-1-area-0.0.0.1]network 192.168.13.0 0.0.0.255 //配置区域1所包含的网段 [AR1-ospf-1-area-0.0.0.1]q [AR1-ospf-1]q AR2:

sy

Enter system view, return user view with Ctrl+Z.

[Huawei]info-center source DS channel 0 log state off trap state off [Huawei]sysn

[Huawei]sysname AR2

[AR2]user-interface console 0 [AR2-ui-console0]idle-timeout 0 0 [AR2-ui-console0]q [AR2]int gi0/0/0

[AR2-GigabitEthernet0/0/0]ip add 192.168.12.2 24 [AR2-GigabitEthernet0/0/0]int gi0/0/1

[AR2-GigabitEthernet0/0/1]ip add 192.168.24.2 24 [AR2-GigabitEthernet0/0/1]int loo0 [AR2-LoopBack0]ip add 2.2.2.2 32 [AR2-LoopBack0]q

OSPF配置：

[AR2]ospf 1 router-id 2.2.2.2

[AR2-ospf-1]area 0 [AR2-ospf-1-area-0.0.0.0]network 192.168.12.0 0.0.0.255 [AR2-ospf-1-area-0.0.0.0]network 2.2.2.2 0.0.0.0

//进入area0区域

//配置区域0所包含的网段

[AR2-ospf-1-area-0.0.0.0]area 2 //定义area2区域 [AR2-ospf-1-area-0.0.0.2]network 192.168.24.0 0.0.0.255 //配置区域2所包含的网段 [AR2-ospf-1-area-0.0.0.2]q [AR2-ospf-1]q AR3:

sy

Enter system view, return user view with Ctrl+Z.

[Huawei]info-center source DS channel 0 log state off trap state off

[Huawei]sysname AR3

[AR3]user-interface console 0 [AR3-ui-console0]idle-timeout 0 0 [AR3-ui-console0]q [AR3]int gi0/0/1

[AR3-GigabitEthernet0/0/1]ip add 192.168.13.3 24 [AR3-GigabitEthernet0/0/1]int loo0 [AR3-LoopBack0]ip add 3.3.3.3 32 OSPF配置：

[AR3]ospf 1 router-id 3.3.3.3

[AR3-ospf-1]area 1 //进入area1区域 [AR3-ospf-1-area-0.0.0.1]network 192.168.13.0 0.0.0.255 //配置区域1所包含的网段 [AR3-ospf-1-area-0.0.0.1]network 3.3.3.3 0.0.0.0 //配置区域1所包含的网段 [AR3-ospf-1-area-0.0.0.1]q [AR3-ospf-1]q AR4:

sy

Enter system view, return user view with Ctrl+Z.

[Huawei]info-center source DS channel 0 log state off trap state off [Huawei]sysname AR4

[AR4]user-interface console 0 [AR4-ui-console0]idle-timeout 0 0 [AR4-ui-console0]q [AR4]int gi0/0/1

[AR4-GigabitEthernet0/0/1]ip add 192.168.24.4 24 [AR4-GigabitEthernet0/0/1]int loo0 [AR4-LoopBack0]ip add 4.4.4.4 32 OSPF配置：

[AR4]ospf 1 router-id 4.4.4.4

[AR4-ospf-1]area 2 //进入area2区域 [AR4-ospf-1-area-0.0.0.2]network 192.168.24.0 0.0.0.255 //配置区域所包含的网段 [AR4-ospf-1-area-0.0.0.2]network 4.4.4.4 0.0.0.0 //配置区域所包含的网段 [AR4-ospf-1-area-0.0.0.2]q [AR4-ospf-1]q

2）查看路由表

#在AR3上显示路由及用ping测试 [AR3]dis ip routing-table //查看路由表（也可用“[AR3]dis ospf routing”这个命令只查看学到的ospf的路由条目）

Route Flags: R - relay, D - download to fib

------------------------------------------------------------------------------ Routing Tables: Public

Destinations : 10 Routes : 10

Destination/Mask Proto Pre Cost Flags NextHop Interface

1.1.1.1/32 OSPF 10 1 D 192.168.13.1 GigabitEthernet 0/0/1

2.2.2.2/32 OSPF 10 2 D 192.168.13.1 GigabitEthernet 0/0/1

3.3.3.3/32 Direct 0 0 D 127.0.0.1 LoopBack0

4.4.4.4/32 OSPF 10 3 D 192.168.13.1 GigabitEthernet 0/0/1

127.0.0.0/8 Direct 0 0 D 127.0.0.1 InLoopBack0 127.0.0.1/32 Direct 0 0 D 127.0.0.1 InLoopBack0 192.168.12.0/24 OSPF 10 2 D 192.168.13.1 GigabitEthernet 0/0/1

192.168.13.0/24 Direct 0 0 D 192.168.13.3 GigabitEthernet 0/0/1

192.168.13.3/32 Direct 0 0 D 127.0.0.1 GigabitEthernet 0/0/1

192.168.24.0/24 OSPF 10 3 D 192.168.13.1 GigabitEthernet 0/0/1

#已经学到了ospf的路由条目

[AR3]ping 4.4.4.4

PING 4.4.4.4: 56 data bytes, press CTRL_C to break

Reply from 4.4.4.4: bytes=56 Sequence=1 ttl=253 time=100 ms Reply from 4.4.4.4: bytes=56 Sequence=2 ttl=253 time=100 ms Reply from 4.4.4.4: bytes=56 Sequence=3 ttl=253 time=80 ms Reply from 4.4.4.4: bytes=56 Sequence=4 ttl=253 time=100 ms Reply from 4.4.4.4: bytes=56 Sequence=5 ttl=253 time=60 ms

--- 4.4.4.4 ping statistics --- 5 packet(s) transmitted 5 packet(s) received 0.00% packet loss

round-trip min/avg/max = 60/88/100 ms #拼AR4的环回口的地址是可以通的

2、查看DR与BDR [AR1]dis ospf peer OSPF Process 1 with Router ID 1.1.1.1 Neighbors

Area 0.0.0.0 interface 192.168.12.1(GigabitEthernet0/0/0)'s neighbors Router ID: 2.2.2.2 Address: 192.168.12.2 #AR1的邻居是AR2，ID是2.2.2.2，地址是192.168.12.2

State: Full Mode:Nbr is Master Priority: 1

DR: 192.168.12.2 BDR: 192.168.12.1 MTU: 0

#由上看出AR1的DR是它对端接口的地址，BDR是它自己接口的地址 Dead timer due in 30 sec Retrans timer interval: 5

Neighbor is up for 00:10:47 Authentication Sequence: [ 0 ] Neighbors

Area 0.0.0.1 interface 192.168.13.1(GigabitEthernet0/0/1)'s neighbors Router ID: 3.3.3.3 Address: 192.168.13.3

#AR1的另一个邻居是AR3，ID是3.3.3.3，地址是192.168.13.3 State: Full Mode:Nbr is Master Priority: 1

DR: 192.168.13.3 BDR: 192.168.13.1 MTU: 0

#AR1-AR3之间的DR是AR3的接口地址，BDR 是AR1的接口的地址 Dead timer due in 34 sec Retrans timer interval: 5

Neighbor is up for 00:10:11 Authentication Sequence: [ 0 ]

[AR4]dis ospf peer OSPF Process 1 with Router ID 4.4.4.4 Neighbors

Area 0.0.0.2 interface 192.168.24.4(GigabitEthernet0/0/1)'s neighbors Router ID: 2.2.2.2 Address: 192.168.24.2 #AR4的邻居只有AR2

State: Full Mode:Nbr is Slave Priority: 1

DR: 192.168.24.4 BDR: 192.168.24.2 MTU: 0

#AR2与AR4之间的DR是AR4的接口，BDR是AR2的接口 Dead timer due in 34 sec Retrans timer interval: 5

Neighbor is up for 00:15:59 Authentication Sequence: [ 0 ]

备注：由上的查看路由邻居可以看出：DR是指某个网段的概念，是针对路由器的接口而言的。某台路由器在一个接口上可能是DR，在另一个接口上有可能是BDR，或者是DR Other。

3、掌握修改OSPF接口优先级的配置 1)先查看未改之前的状态

? 查看一下AR1上关于ospf的接口的优先级 dis ospf interface

OSPF Process 1 with Router ID 1.1.1.1 Interfaces

Area: 0.0.0.0 (MPLS TE not enabled)

IP Address Type State Cost Pri DR BDR

192.168.12.1 Broadcast BDR 1 1 192.168.12.2 192.168.12. 1

1.1.1.1 P2P P-2-P 0 1 0.0.0.0 0.0.0.0

Area: 0.0.0.1 (MPLS TE not enabled)

IP Address Type State Cost Pri DR BDR

192.168.13.1 Broadcast BDR 1 1 192.168.13.3 192.168.13. 1

#这时的gi0/0/1的接口的优先级是默认的1

? 查看路由邻居，这时要在AR3上看的，因为它的邻居接口是AR1上的gi0/0/1，后面改

这个接口的优先级才能看出的 [AR3]dis ospf peer OSPF Process 1 with Router ID 3.3.3.3 Neighbors

Area 0.0.0.1 interface 192.168.13.3(GigabitEthernet0/0/1)'s neighbors Router ID: 1.1.1.1 Address: 192.168.13.1 State: Full Mode:Nbr is Slave Priority: 1

#AR3的neighbors是ID号1.1.1.1的，地址 是192.168.13.1的且优先级是1，注意一下下面的DR与BDR，后面改接口之后会有变化的

DR: 192.168.13.3 BDR: 192.168.13.1 MTU: 0 Dead timer due in 34 sec Retrans timer interval: 5

Neighbor is up for 00:04:21 Authentication Sequence: [ 0 ]

2）执行下面的命令改接口的优先级

[AR1]int gi0/0/1 （改的是AR1与AR3的对连接口）

[AR1-GigabitEthernet0/0/1]ospf dr-priority 10 //将优先级改为10 [AR1-GigabitEthernet0/0/1] 按Ctrl+z组合键 reset ospf 1 process //重启一下进程（因为DR优先级在配置之后并不会立即生效）

reset ospf 1 process //在AR3也要重启一下，重新学习一下DR与BDR

1查看一下改过之后的变化 ○

? 查看一下AR1上关于ospf的接口的优先级

dis ospf interface OSPF Process 1 with Router ID 1.1.1.1 Interfaces

Area: 0.0.0.0 (MPLS TE not enabled)

IP Address Type State Cost Pri DR BDR

192.168.12.1 Broadcast BDR 1 1 192.168.12.2 192.168.12. 1

1.1.1.1 P2P P-2-P 0 1 0.0.0.0 0.0.0.0

Area: 0.0.0.1 (MPLS TE not enabled)

IP Address Type State Cost Pri DR BDR

192.168.13.1 Broadcast BDR 1 10 192.168.13.3 192.168.13. 1

#这时的gi0/0/1的接口的优先级10

? 再查看OSPF的邻居 [AR3]dis ospf peer OSPF Process 1 with Router ID 3.3.3.3 Neighbors

Area 0.0.0.1 interface 192.168.13.3(GigabitEthernet0/0/1)'s neighbors Router ID: 1.1.1.1 Address: 192.168.13.1 State: Full Mode:Nbr is Slave Priority: 10 #优先级已经变成了10，就连DR与BDR也变化了 DR: 192.168.13.1 BDR: 192.168.13.3 MTU: 0 Dead timer due in 40 sec Retrans timer interval: 5

Neighbor is up for 00:02:34 Authentication Sequence: [ 0 ]

4、掌握修改OSPF cost的配置

1在gi0/0/0口改cost值，先查看一下它之前的接口cost是1如下 ○

[AR1]dis ospf int gi0/0/0 OSPF Process 1 with Router ID 1.1.1.1 Interfaces

Interface: 192.168.12.1 (GigabitEthernet0/0/0)

Cost: 1 State: BDR Type: Broadcast MTU: 1500 Priority: 1

Designated Router: 192.168.12.2

Backup Designated Router: 192.168.12.1

Timers: Hello 10 , Dead 40 , Poll 120 , Retransmit 5 , Transmit Delay 1

2未改之前的ospf的cost值如下 ○

[AR1]dis ip routing-table

Route Flags: R - relay, D - download to fib

------------------------------------------------------------------------------ Routing Tables: Public

Destinations : 11 Routes : 11

Destination/Mask Proto Pre Cost Flags NextHop Interface

1.1.1.1/32 Direct 0 0 D 127.0.0.1 LoopBack0

2.2.2.2/32 OSPF 10 1 D 192.168.12.2 GigabitEthernet 0/0/0

3.3.3.3/32 OSPF 10 1 D 192.168.13.3 GigabitEthernet 0/0/1

4.4.4.4/32 OSPF 10 2 D 192.168.12.2 GigabitEthernet 0/0/0

127.0.0.0/8 Direct 0 0 D 127.0.0.1 InLoopBack0 127.0.0.1/32 Direct 0 0 D 127.0.0.1 InLoopBack0 192.168.12.0/24 Direct 0 0 D 192.168.12.1 GigabitEthernet 0/0/0

192.168.12.1/32 Direct 0 0 D 127.0.0.1 GigabitEthernet 0/0/0

192.168.13.0/24 Direct 0 0 D 192.168.13.1 GigabitEthernet 0/0/1

192.168.13.1/32 Direct 0 0 D 127.0.0.1 GigabitEthernet 0/0/1

192.168.24.0/24 OSPF 10 2 D 192.168.12.2 GigabitEthernet 0/0/0

3修改cost命令如下 ○

[AR1]int gi0/0/0

[AR1-GigabitEthernet0/0/0]ospf cost 20 [AR1]dis ospf interface gi0/0/0 OSPF Process 1 with Router ID 1.1.1.1 Interfaces

Interface: 192.168.12.1 (GigabitEthernet0/0/0)

Cost: 20 State: BDR Type: Broadcast MTU: 1500 #修改完之后，cost值变为20 Priority: 1

Designated Router: 192.168.12.2

Backup Designated Router: 192.168.12.1

Timers: Hello 10 , Dead 40 , Poll 120 , Retransmit 5 , Transmit Delay 1

4修改之后ospf的cost值 ○

[AR1]dis ip routing-table

Route Flags: R - relay, D - download to fib

------------------------------------------------------------------------------ Routing Tables: Public

Destinations : 11 Routes : 11

Destination/Mask Proto Pre Cost Flags NextHop Interface

1.1.1.1/32 Direct 0 0 D 127.0.0.1 LoopBack0

2.2.2.2/32 OSPF 10 20 D 192.168.12.2 GigabitEthernet 0/0/0

3.3.3.3/32 OSPF 10 1 D 192.168.13.3 GigabitEthernet 0/0/1

4.4.4.4/32 OSPF 10 21 D 192.168.12.2 GigabitEthernet 0/0/0

127.0.0.0/8 Direct 0 0 D 127.0.0.1 InLoopBack0 127.0.0.1/32 Direct 0 0 D 127.0.0.1 InLoopBack0 192.168.12.0/24 Direct 0 0 D 192.168.12.1 GigabitEthernet 0/0/0

192.168.12.1/32 Direct 0 0 D 127.0.0.1 GigabitEthernet 0/0/0

192.168.13.0/24 Direct 0 0 D 192.168.13.1 GigabitEthernet 0/0/1

192.168.13.1/32 Direct 0 0 D 127.0.0.1 GigabitEthernet 0/0/1

192.168.24.0/24 OSPF 10 21 D 192.168.12.2 GigabitEthernet 0/0/0

四、思考与感想

1、DR与BDR的说明

DR（Designated Router）：指定路由器。

所有路由器都只将信息发送给DR，由DR将网络链路状态广播出去，除DR/BDR外的路由器（称为DR Other）之间将不再建立邻居关系，也不再交换任何路由信息。哪一台路由器会成

为本网段内的DR并不是人为指定的，而是由本网段中所有的路由器共同选举出来的。当处于同一网段的两台路由器同时宣布自己是DR时，DR优先级高者胜出。如果优先级相等，则Router ID大者胜出。

BDR（Backup Designated Router）：备份指定路由器。

BDR实际上是对DR的一个备份，在选举DR的同时也选举出BDR，BDR也和本网段内的所有路由器建立邻接关系并交换路由信息。当DR失效后，BDR会立即成为DR。

2、配置区域所包含的网段

一个网段只能属于一个区域，或者说每个运行OSPF协议的接口必须指明属于某一个特定的区域。该处的网段是指运行OSPF协议接口的IP地址所在的网段。

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