OSPF comprehensive experiment

 1. Experimental requirements and topological diagram

 2. Divide well IP The topology of

 3. experimental analysis

        1, R4 by ISP, Can only be configured on it IP Address ; R4 Public equipment is used with all other directly connected equipment IP

                And ISP Direct connected devices need to be configured to point ISP The default route for ( Here only R3 To configure ), Private network wants ping Connect to the public network and configure NAT

[r3]ip route-static 0.0.0.0 0 172.16.32.3

[r3]acl 2000	
[r3-acl-basic-2000]rule permit source 172.16.32.0 0.0.31.255
[r3-acl-basic-2000]int s 4/0/0
[r3-Serial4/0/0]nat outbound 2000

2,R3,R5/6/7 by MGRE Environmental Science ,R3 For the central site

r3 Central configuration

[r3]int t 0/0/0
[r3-Tunnel0/0/0]ip ad 172.16.24.1 21
[r3-Tunnel0/0/0]tunnel-protocol gre p2mp
[r3-Tunnel0/0/0]source 34.0.0.1
[r3-Tunnel0/0/0]nhrp network-id 100
[r3-Tunnel0/0/0]nhrp entry b d

 R5/6/7 To configure （ Are similar , Here only configure R5, If you want to see similar detailed configurations , see (51 Bar message ) PPP,GRE,MGRE,RIP Related experiments _qq_52178594 The blog of -CSDN Blog ）

[r5]int t 0/0/0
[r5-Tunnel0/0/0]ip ad 172.16.24.2 21
[r5-Tunnel0/0/0]tunnel-protocol gre p2mp
[r5-Tunnel0/0/0]source s 4/0/0
Jul 17 2022 18:58:34-08:00 r5 %%01IFNET/4/LINK_STATE(l)[0]:The line protocol IP 
on the interface Tunnel0/0/0 has entered the UP state. 
[r5-Tunnel0/0/0]nhrp network-id 100
[r5-Tunnel0/0/0]nhrp entry 172.16.24.1 34.0.0.1 register 

        3, Whole OSPF Environmental Science IP be based on 172.16.0.8/16 Divide ;

                IP The first step of configuration has been divided , A little

To configure OSPF Environmental Science （GRE In the environment, you also need to modify the network type of the interface , Otherwise, it is impossible to build neighbors ）

[r1]ospf 1r	
[r1]ospf 1 r	
[r1]ospf 1 router-id 1.1.1.1
[r1-ospf-1]a 1
[r1-ospf-1-area-0.0.0.1]net 172.16.32.0 0.0.31.255


[r2]ospf 1 r	
[r2]ospf 1 router-id 2.2.2.2
[r2-ospf-1]a 1
[r2-ospf-1-area-0.0.0.1]net	
[r2-ospf-1-area-0.0.0.1]network 172.16.32.0 0.0.31.255

[r3]ospf
[r3-ospf-1]a 0
[r3-ospf-1-area-0.0.0.0]net 172.16.24.0 0.0.7.255
	
[r4]ospf 1 router-id 4.4.4.4
[r4-ospf-1]a 0
[r4-ospf-1-area-0.0.0.0]net	
[r4-ospf-1-area-0.0.0.0]network 4.4.4.4 0.0.0.0
[r4-ospf-1-area-0.0.0.0]net 47.0.0.2 0.0.0.0
[r4-ospf-1-area-0.0.0.0]network 4.4.4.4 0.0.0.255

（R5-R12 The configurations are similar , A little ）

4, All devices are accessible R4 The loopback of ;

        To configure NAT service , See step one
5, Reduce LSA Update quantity of , Speed up convergence , To ensure the security of updates ;

        Reduce LSA Update quantity of ： Route summary between regions and within regions , Configure special areas （ABR The device is configured with ）

 Area 1 To configure （ Completely peripheral area ）
[r1-ospf-1-area-0.0.0.1]stub
[r2-ospf-1-area-0.0.0.1]stub

[r3-ospf-1-area-0.0.0.1]abr-summary 172.16.32.0 255.255.224.0
[r3-ospf-1-area-0.0.0.1]stub
[r3-ospf-1-area-0.0.0.1]stub no-summary
[r3]ip route-static 172.16.32.0 19 NULL 0  ( After the summary is completed, an empty interface needs to be configured , Otherwise, black hole routing will occur )


 Area 2（NSSA Area , Summary omitted ）
[r6]ospf
[r6-ospf-1]a 2
[r6-ospf-1-area-0.0.0.2]nssa no-summary


[r11-ospf-1-area-0.0.0.2]nssa
[r12-ospf-1-area-0.0.0.2]nssa


 Area 3 It's also NSSA Area , The configuration is the same as above 


 Area 4
ABR Individual republication on the equipment , And issue a default 
[r9-ospf-1]import ospf 1
[r9-ospf-2]default-route-advertise

         Speed up convergence ： modify Hello Packet time (gre Just change it in the environment , Others are ten seconds , Not too fast )

[r3-Tunnel0/0/0]ospf timer hello 10
[r5-Tunnel0/0/0]ospf timer hello 10
[r6-Tunnel0/0/0]ospf timer hello 10
[r7-Tunnel0/0/0]ospf timer hello 10

         To ensure the security of updates ： Conduct manual certification （ Regional certification is enough , Interface authentication requires configuration one by one ）

[r3-ospf-1-area-0.0.0.1]authentication-mode md5 1 cipher 123456