Configuring OSPF experiment in mGRE environment

1. Experimental requirements and topological diagram ：

2. Match well IP The topology of is shown below ;

3. experimental analysis

        1.R6 by ISP You can only configure IP Address ,R1—R5 The loopback of is a private network segment

                ISP The router only IP To configure , therefore R1--R5 Need to configure pointing ISP The default route of the router

[r1]ip route-static 0.0.0.0 0 16.0.0.2    (r1 Default )
[r1]ip route-static 0.0.0.0 0 161.0.0.2


[r2]ip route-static 0.0.0.0 0 26.0.0.2    (r2 Default )


[r3]ip route-static 0.0.0.0 0 36.0.0.2    (r3 Default )


[r4]ip route-static 0.0.0.0 0 46.0.0.2    (r4 Default )


[r5]ip route-static 0.0.0.0 0 56.0.0.2    (r5 Default )

        2.R1/4/5 For the whole company MGRE structure ,R1/2/3 Is a star topology ,R1 For the central site  

                r1/r2/r3, among r1 Centered , So according to the configuration MGRE Step by step , And open the pseudo broadcast domain

                R1/4/5 For the whole company MGRE structure , That is, each router is the center , You need to report yourself to other routes

        R1:

[r1]int t 0/0/0
[r1-Tunnel0/0/0]ip ad 192.168.6.1 24
[r1-Tunnel0/0/0]tunnel-protocol gre p2mp
[r1-Tunnel0/0/0]source 16.0.0.1
[r1-Tunnel0/0/0]nhrp neteork-id 100
[r1-Tunnel0/0/0]nhrp entry multicast dynamic

[r1]int t 0/0/1
[r1-Tunnel0/0/1]ip ad 192.168.7.1 24
[r1-Tunnel0/0/1]tunnel-protocol gre p2mp
[r1-Tunnel0/0/1]source 161.0.0.1
[r1-Tunnel0/0/1]nhrp neteork-id 101
[r1-Tunnel0/0/1]nhrp entry multicast dynamic
[r1-Tunnel0/0/1]nhrp entry 192.168.7.2 46.0.0.1 register
[r1-Tunnel0/0/1]nhrp entry 192.168.7.3 56.0.0.1 register

        R2;

[r2]int t 0/0/0
[r2-Tunnel0/0/0]ip ad 192.168.6.2 24	
[r2-Tunnel0/0/0]tunnel-protocol gre p2mp	
[r2-Tunnel0/0/0]source GigabitEthernet 0/0/0
Jul 13 2022 16:18:11-08:00 r2 %%01IFNET/4/LINK_STATE(l)[0]:The line protocol IP 
on the interface Tunnel0/0/0 has entered the UP state. 	
[r2-Tunnel0/0/0]nhrp network-id 100
[r2-Tunnel0/0/0]nhrp entry 192.168.6.1 16.0.0.1 register 

        R3:

[r3]int t 0/0/0
[r3-Tunnel0/0/0]ip ad 192.168.6.3 24
[r3-Tunnel0/0/0]tunnel-protocol gre p2mp	
[r3-Tunnel0/0/0]source GigabitEthernet 0/0/0
Jul 13 2022 16:20:09-08:00 r3 %%01IFNET/4/LINK_STATE(l)[0]:The line protocol IP 
on the interface Tunnel0/0/0 has entered the UP state. 
[r3-Tunnel0/0/0]nhrp network-id 100
[r3-Tunnel0/0/0]nhrp entry 192.168.6.1 16.0.0.1 register 

        R4:

[r4]int t 0/0/0
[r4-Tunnel0/0/0]ip ad 192.168.7.2 24
[r4-Tunnel0/0/0]tunnel-protocol gre p2mp
[r4-Tunnel0/0/0]source 46.0.0.1
Jul 13 2022 16:25:29-08:00 r4 %%01IFNET/4/LINK_STATE(l)[0]:The line protocol IP 
on the interface Tunnel0/0/0 has entered the UP state. 
[r4-Tunnel0/0/0]nhrp network-id 101	
[r4-Tunnel0/0/0]nhrp entry multicast d	
[r4-Tunnel0/0/0]nhrp entry 192.168.7.3 56.0.0.1 register 
[r4-Tunnel0/0/0]nhrp entry 192.168.7.1 161.0.0.1 register ( Those reported on other routers can be omitted )
Info: This peer protocol address conflicts with hub register peer protocol addre
ss. 

         R5：

[r5]int t 0/0/0
[r5-Tunnel0/0/0]ip ad 192.168.7.3 24
[r5-Tunnel0/0/0]tunnel-protocol gre p2mp
[r5-Tunnel0/0/0]source 56.0.0.1
Jul 13 2022 16:26:46-08:00 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 101
[r5-Tunnel0/0/0]n e m d	

         3., All private network segments can communicate with each other , Private network segment use OSPF complete .

                MGRE Environment interface ospf The network type of needs to be modified ( If it is not modified, the adjacency relationship cannot be established )

                R1-R3 The interface is changed to p2mp,R1,R4,R5 Change it to boardcast

        R1(R2-R5 The configurations are similar , A little ):

[r1]ospf 1 router-id 1.1.1.1
[r1-ospf-1]area 0
[r1-ospf-1-area-0.0.0.0]network 192.168.1.0 0.0.0.255
[r1-ospf-1-area-0.0.0.0]network 192.168.6.0 0.0.0.255
[r1-ospf-1-area-0.0.0.0]network 192.168.7.0 0.0.0.255

4. Verification of experimental results ：

MGRE result ：

  Network connectivity ：