OSPF configuration in mGRE environment and LSA optimization - reduce the amount of LSA updates (summary, special areas)

The experimental requirements

 

Build the experimental sketch into a topology

IP Address planning  

Experimental requirements are based on 172.16.0.0/16 Conduct IP Address planning

There are six areas in this experiment --- Six network segments are required --- Excuse me

172.16.0.0/19
172.16.32.0/19
172.16.64.0/19
172.16.96.0/19
172.16.128.0/19
172.16.160.0/19
172.16.192.0/19
172.16.224.0/19

Take six network segments from them and give them to the corresponding six areas

Area 1：172.16.0.0/19

Three loops + A backbone link = Four network segments --- Excuse me

172.16.0.0/21
172.16.8.0/21
172.16.16.0/21
172.16.24.0/21

Area 0：172.16.32.0/19

Three loops +Tunnel= Four network segments --- Excuse me

172.16.32.0/21
172.16.40.0/21
172.16.48.0/21
172.16.56.0/21

Area 2：172.16.64.0/19

A loopback + Two backbone links = Three network segments --- Excuse me

172.16.64.0/21
172.16.72.0/21
172.16.80.0/21

Area 3：172.16.96.0/19

A loopback + Two backbone links = Three network segments --- Excuse me

172.16.96.0/21
172.16.104.0/21
172.16.112.0/21

Area 4：172.16.128.0/19

Two loops + A backbone link = Three network segments --- Excuse me

172.16.128.0/21
172.16.136.0/21
172.16.144.0/21

RIP：172.16.160.0/19

Two loops --- Two segments --- Borrow one

172.16.160.0/20
172.16.176.0/20

IP Address configuration

According to the network segment divided in the previous step , Give each interface a valid IP Address , After each router is configured , Go separately ping It connects directly to the interface , Ensure that the next step of configuration is carried out after it is fully connected .

Default and NAT Address translation

stay R3、R5、R6、R7 There is a default , All point to the corresponding R4 On the interface

With R3 For example

 [R3]ip route-static 0.0.0.0 0 34.1.1.4

Press this operation to complete R5、R6、R7

NAT Address translation

[R3]acl 2000
[R3-acl-basic-2000]rule 1 permit source any 
[R3-acl-basic-2000]int s3/0/0
[R3-Serial3/0/0]nat outbound 2000

In the same way R5、R6、R7

MGRE Environment building

The experimental requirements ：R3、R5、R6、R7 by MGRE Environmental Science ,R3 For the central site

R3--- Central site configuration

[R3]int t0/0/0
[R3-Tunnel0/0/0]ip add 10.1.1.1 24
[R3-Tunnel0/0/0]tunnel-protocol gre p2mp 

[R3-Tunnel0/0/0]source 34.1.1.3
[R3-Tunnel0/0/0]nhrp entry multicast dynamic 
[R3-Tunnel0/0/0]nhrp network-id 100

R5--- Branch site configuration

[R5]int t0/0/0
[R5-Tunnel0/0/0]ip add 10.1.1.2 24
[R5-Tunnel0/0/0]tunnel-protocol gre p2mp 
[R5-Tunnel0/0/0]source s4/0/0
[R5-Tunnel0/0/0]nhrp entry 10.1.1.1 34.1.1.3 register 
[R5-Tunnel0/0/0]nhrp network-id 100

R6 And R7 Configuration mode and R5 identical

When it's done R3 Check whether the registration is successful

 

 

 OSPF Announcement of

At the time of the announcement ,MGRE The working mode of the interface should be modified in the environment , from p2p Change it to broadcast, And interfere in the election , Other network segments are normally declared by Region

Modify the interface type

[R3]int t0/0/0

[R3-Tunnel0/0/0]ospf network-type broadcast

Interference in elections ---R5--R7 Give up the election

[R5]int tunnel 0/0/0

[R5-Tunnel0/0/0]ospf dr-priority 0

 

  Multi process bidirectional republication

Area 4

[R9]ospf 1

[R9-ospf-1]import-route ospf 2

RIP Area

[R12]ospf 1
[R12-ospf-1]import-route rip 1

Inter domain routing summary

The inter domain routing sink is always ABR On , In this experiment, it is in R3、R6、R7

[R3]ospf 1
[R3-ospf-1]area 1
[R3-ospf-1-area-0.0.0.1]abr-summary 172.16.0.0 255.255.224.0 

In the same way R6、R7 A summary of

Extraterritorial routing summary

The extraterritorial routing sink is always ASBR On , This experiment is R9、R12

[R9]ospf 1
[R9-ospf-1]area 4
[R9-ospf-1-area-0.0.0.4]abr-summary 172.16.128.0 255.255.224.0

  In the same way R12

Air interface anti ring

Due to the summary above , To prevent loop generation , Configure an empty interface on each summarized router

[r1]ip route-static 1.1.0.0 22 NULL 0

                      （ The summarized network segment ）

  Special area

Special area ： It can't be the backbone area , Nor can there be virtual links

（1） At the same time, I will never be ASBR--- The terminal area

（2） At the same time, from ASBR---NSSA Area

Therefore, in this experiment , Area 1 Is the terminal area , Area 2、3 by NSSA Area

Area 1

[R1]ospf 1
[R1-ospf-1]area 1
[R1-ospf-1-area-0.0.0.1]stub

All equipment in this area needs to be defined , Otherwise, you can't establish a neighbor relationship

Completely peripheral area , Further reject on the basis of the peripheral region 3 Class LSA, Keep only one 3 Class , First, configure this area as a terminal area , And then only in ABR Just define the complete end on the

R3（ABR）

[R3]ospf 1
[R3-ospf-1]area 1
[R3-ospf-1-area-0.0.0.1]stub no-summary 

Area 2、3

[R7]ospf 1
[R7-ospf-1]area 3
[R7-ospf-1-area-0.0.0.3]nssa

  All equipment in this area needs to be defined , Otherwise, you can't establish a neighbor relationship

Completely NSSA – Complete and incomplete peripheral regions ; In general NSSA On the basis of , Step closer and refuse 3 Class LSA, from ABR Generate a 3 Class default , First, configure the area as normal NSSA, And then only in ABR Completely defined NSSA that will do

R7（ABR）

[R7]ospf 1
[R7-ospf-1]area 3
[R7-ospf-1-area-0.0.0.3]nssa no-summary 

Similarly, complete the area 2 The optimization of the  

You can check their lsdb Database table

 

 

  It can be seen that the terminal area is related to NSSA There is no such area 4、5 class LSA The birth of , Only one is reserved 3 The default point of class ABR

So far, the purpose of the experiment has been achieved , End of experiment