[hcip] two mGRE networks are interconnected through OSPF (ENSP)

Experimental requirements and topology

1. R4 by ISP, All physical interfaces connected are common network segments
2. R1-2-3 Build a star structure MGRE, among R1 For the central site
3. R1-5-6 Build a fully connected mesh MGRE, among R1/5 All are central sites
4. Use OSPF Realize the interworking of the whole private network , All at the same time PC Normal access R4 The loopback of
   

Experimental process

IP To configure

With R4(ISP) For example

[ISP]interface LoopBack 0
[ISP-LoopBack0]ip address 4.4.4.4 24	// Public network IP
[ISP-LoopBack0]quit
[ISP]interface g0/0/0
[ISP-GigabitEthernet0/0/0]ip address 21.1.1.4 24
[ISP-GigabitEthernet0/0/0]quit
[ISP]interface g0/0/1
[ISP-GigabitEthernet0/0/1]ip address 12.1.1.4 24
[ISP-GigabitEthernet0/0/1]quit
[ISP]interface g0/0/2
[ISP-GigabitEthernet0/0/2]ip address 23.1.1.4 24
[ISP-GigabitEthernet0/0/2]quit
[ISP]interface g4/0/0
[ISP-GigabitEthernet4/0/0]ip address 34.1.1.4 24
[ISP-GigabitEthernet4/0/0]quit
[ISP]interface g4/0/1
[ISP-GigabitEthernet4/0/1]ip address 45.1.1.4 24
[ISP-GigabitEthernet4/0/1]quit
[ISP]interface g4/0/2
[ISP-GigabitEthernet4/0/2]ip address 56.1.1.4 24

Star type MGRE

First configure R1-6 Point to ISP Default （ Don't show ）

//R1( Central site )
[R1]interface Tunnel 0/0/0
[R1-Tunnel0/0/0]ip address 10.1.1.1 24
[R1-Tunnel0/0/0]tunnel-protocol gre p2mp
[R1-Tunnel0/0/0]source 12.1.1.1
Jul 22 2022 18:55:09-08:00 R1 %%01IFNET/4/LINK_STATE(l)[0]:The line protocol IP on the interface Tunnel0/0/0 has entered the UP state.
[R1-Tunnel0/0/0]nhrp entry multicast dynamic
[R1-Tunnel0/0/0]nhrp network-id 100
//R2
[R2]interface Tunnel 0/0/0
[R2-Tunnel0/0/0]ip address 10.1.1.2 24
[R2-Tunnel0/0/0]tunnel-protocol gre p2mp
[R2-Tunnel0/0/0]source g0/0/0
Jul 22 2022 18:57:24-08:00 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 10.1.1.1 12.1.1.1 register 
//R3
[R3]interface Tunnel 0/0/0
[R3-Tunnel0/0/0]ip address 10.1.1.3 24
[R3-Tunnel0/0/0]tunnel-protocol gre p2mp
[R3-Tunnel0/0/0]source g0/0/0
Jul 22 2022 18:58:59-08:00 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 10.1.1.1 12.1.1.1 register 

The whole company MGRE

//R1( Central site )
[R1]interface Tunnel 0/0/1
[R1-Tunnel0/0/1]ip address 20.1.1.1 24
[R1-Tunnel0/0/1]tunnel-protocol gre p2mp
[R1-Tunnel0/0/1]source 21.1.1.1
Jul 22 2022 19:06:32-08:00 R1 %%01IFNET/4/LINK_STATE(l)[0]:The line protocol IP on the interface Tunnel0/0/1 has entered the UP state.
[R1-Tunnel0/0/1]nhrp entry multicast dynamic
[R1-Tunnel0/0/1]nhrp network-id 200
//R5( Central site )
[R5]interface Tunnel 0/0/1
[R5-Tunnel0/0/1]ip address 20.1.1.5 24
[R5-Tunnel0/0/1]tunnel-protocol gre p2mp
[R5-Tunnel0/0/1]source 45.1.1.5
Jul 22 2022 19:08:26-08:00 R5 %%01IFNET/4/LINK_STATE(l)[0]:The line protocol IP on the interface Tunnel0/0/1 has entered the UP state.
[R5-Tunnel0/0/1]nhrp entry multicast dynamic
[R5-Tunnel0/0/1]nhrp network-id 200
[R5-Tunnel0/0/1]nhrp entry 20.1.1.1 21.1.1.1 register 
//R6
[R6]interface Tunnel 0/0/1
[R6-Tunnel0/0/1]ip address 20.1.1.6 24
[R6-Tunnel0/0/1]tunnel-protocol gre p2mp
[R6-Tunnel0/0/1]source 56.1.1.6
Jul 22 2022 19:10:02-08:00 R6 %%01IFNET/4/LINK_STATE(l)[0]:The line protocol IP on the interface Tunnel0/0/1 has entered the UP state. 
[R6-Tunnel0/0/1]nhrp network-id 200
[R6-Tunnel0/0/1]nhrp entry 20.1.1.1 21.1.1.1 register
[R6-Tunnel0/0/1]nhrp entry 20.1.1.5 45.1.1.5 register

OSPF

//R1(area 0 + area 1)
[R1]ospf 1 router-id 1.1.1.1
[R1-ospf-1]area 0
[R1-ospf-1-area-0.0.0.0]network 192.168.1.1 0.0.0.0
[R1-ospf-1-area-0.0.0.0]network 10.1.1.1 0.0.0.0
[R1-ospf-1-area-0.0.0.0]quit
[R1-ospf-1]area 1
[R1-ospf-1-area-0.0.0.1]network 20.1.1.1 0.0.0.0
//R2(area 0)
[R2]ospf 1 router-id 2.2.2.2
[R2-ospf-1]area 0
[R2-ospf-1-area-0.0.0.0]network 192.168.2.1 0.0.0.0
[R2-ospf-1-area-0.0.0.0]network 10.1.1.2 0.0.0.0
//R3(area 0)
[R3]ospf 1 router-id 3.3.3.3
[R3-ospf-1]area 0
[R3-ospf-1-area-0.0.0.0]network 192.168.3.1 0.0.0.0
[R3-ospf-1-area-0.0.0.0]network 10.1.1.3 0.0.0.0
//R5(area 1)
[R5]ospf 1 router-id 5.5.5.5
[R5-ospf-1]area 1
[R5-ospf-1-area-0.0.0.1]network 192.168.4.1 0.0.0.0
[R5-ospf-1-area-0.0.0.1]network 20.1.1.5 0.0.0.0
//R6(area 1)
[R6]ospf 1 router-id 6.6.6.6
[R6-ospf-1]area 1
[R6-ospf-1-area-0.0.0.1]ne
[R6-ospf-1-area-0.0.0.1]network 192.168.5.1 0.0.0.0
[R6-ospf-1-area-0.0.0.1]ne
[R6-ospf-1-area-0.0.0.1]network 20.1.1.6 0.0.0.0

stay NBMA In the network , The interface type is p2p, so OSPF The agreement cannot normally establish a neighbor relationship , At this time, all interfaces should be modified to Broadcast;
R2 and R3 In star MGRE In the network , And make it give up DR The election , otherwise area 0 The route selection will be inconsistent

//R1
[R1]interface Tunnel 0/0/0
[R1-Tunnel0/0/0]ospf network-type broadcast 
[R1-Tunnel0/0/0]quit
[R1]interface Tunnel 0/0/1
[R1-Tunnel0/0/1]ospf network-type broadcast 
//R2
[R2]interface Tunnel 0/0/0
[R2-Tunnel0/0/0]ospf network-type broadcast
[R2-Tunnel0/0/0]ospf dr-priority 0
//R3
[R3]interface Tunnel 0/0/0
[R3-Tunnel0/0/0]ospf network-type broadcast
[R3-Tunnel0/0/0]ospf dr-priority 0
//R5
[R5]interface Tunnel 0/0/1
[R5-Tunnel0/0/1]ospf network-type broadcast 
//R6
[R6]interface Tunnel 0/0/1
[R6-Tunnel0/0/1]ospf network-type broadcast 

NAT address translation , With R1 For example

[R1]acl 2000
[R1-acl-basic-2000]rule 1 permit source any 
[R1-acl-basic-2000]q
[R1]int g0/0/1
[R1-GigabitEthernet0/0/1]nat outbound 2000

Routing table display and connectivity test