OSPF basic configuration application (comprehensive experiment: interference election default routing area summary authentication -- interface authentication)

Catalog

  Comprehensive experiment :

  Interference in elections

  Default route  

  Regional summary

  authentication -- Interface authentication

  Passive interface

  Fast convergence plus

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  Comprehensive experiment :

First step ： Subnet partition

        First of all to IP Address planning , The experimental requirements R4 Loopback fixation , Other network segments use 192.168.1.0/24 division .R1—R3 Is the region 0,R3—R4 Is the region 1, Each of them has a loopback ,R3 Loop back in area 0.

Two regions , Let's divide the master network into two , obtain 192.168.1.0/25 And 192.168.1.128/25  This will facilitate the regional summary later . Then it is divided according to the needs of the two regions , Area 0 need 4 Net segment (3 Loop back + Backbone links ), Area 1 need 1 Net segment ( Backbone links )

  be used for R3—R4 The network segment between them is directly delimited to 30 position , Because this network segment only needs two IP

The second step ：IP To configure

Follow the first step IP Planning IP To configure

With R1 For example

[R1]interface GigabitEthernet 0/0/0
[R1-GigabitEthernet0/0/0]ip address 192.168.1.1 27

[R1]interface loopback 0
[R1-LoopBack0]ip address 192.168.1.33 27

Configure all IP

The third step ： ospf To configure

First ospf Start of , Process number and id To configure

The process number can be defined at startup 、RID, Default process 1,RID-- The format is IPV4 Address , The whole network is unique

[R1]ospf 1 router-id 192.168.1.1

Then select and announce the region

[R1-ospf-1]area 0
[R1-ospf-1-area-0.0.0.0]network 192.168.1.1 0.0.0.31

notes :ospf When declaring, the mask needs to be unmasked to declare  

And then in turn R2—R4 Make an announcement , Notice the announcement R3 Of g0/0/1 Mouth and R4 when , Declare the area to be an area 1（area 1）

  Interference in elections

The experimental requirements R3 by DR equipment , No, BDR. So we have to intervene in the election , Change priority . because ospf The election is non preemptive , So after modifying the priority , All routers need to be restarted OSPF process . In order not to restart the process , We can DR The priority is changed to maximum , Other equipment is modified as 0（ Deemed to have waived ）, There is no need to restart the process .

[R3]int g0/0/0  （ The port to participate in the election ）

[R3-GigabitEthernet0/0/0]ospf dr-priority 255

Press this operation to change the priority of other devices to 0, Then you can view the neighbor table of any router in this area

 

<R3>display ospf peer 

 

We can see 0 Regional DR by R3 Of id

  Default route  

Experimental requirements cannot be declared R4 The loopback of , So we need to configure the default route on the border router , That is to say R4 On

 

 

[R4]ospf 1

[R4-ospf-1]default-route-advertise always 

  Regional summary

In order to minimize the number of routing entries , We can 0 Summarize by Region

notes ：OSPF The protocol does not support interface summary , Only in ABR（R3） Admiral 0 Route calculated by regional topology , Share with 1 Summarize when area

[R3]ospf 1

[R3-ospf-1]area 0

[R3-ospf-1-area-0.0.0.0]abr-summary 192.168.1.0 255.255.128

After summary, you can view R4 You can find 0 There is only one route in the area  

[R4]display ip routing-table protocol ospf

 

  authentication -- Interface authentication

The experiment requires that the update is safe , We need to configure directly connected neighbors or adjacent interfaces , In order to ensure the security of update

 

[R2]int g0/0/0

[R2-GigabitEthernet0/0/0]ospf authentication-mode md5 1 cipher 123456

                                                                              Pattern     Number         password

Mode of each interface 、 Number 、 The password requires consistency between neighbors , Otherwise, the topology cannot be shared

So far, all the experimental requirements have been met , End of experiment .

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Add :

  Passive interface

Also called silent interface -- Only receive and do not send routing protocol information , Interface for connecting user terminals , It shall not be used to connect the interface of neighbor router , Otherwise, you can't establish a neighbor relationship .

[r2]ospf 1

[r2-ospf-1]silent-interface GigabitEthernet 0/0/0

  Fast convergence plus

  Neighbor timer   10s hello time  40s dead time 

Between neighbors , Modify the local hello time, Local dead time Automatically 4 Matched by relationships , but ospf Between neighbors hello time and dead time It has to be exactly the same , Otherwise, you can't establish a neighbor relationship .

[r1]interface GigabitEthernet 0/0/0

[r1-GigabitEthernet0/0/0]ospf timer  hello 5