Hi Experts,
I am trying to set up a DMVPN design with a single cloud and dual hub, routing via BGP.
Currently, both hub routers have the MPGRE tunnels (Tunnel0, NHRP ID 12345, Subnet 10.0.0.0/24) configured. To enable NHRP between the hub routers, I configured an additional tunnel via the LAN (Tunnel1, same NHRP ID, Subnet 10.2.0.0/30). The BGP neighborship is established via the LAN interfaces, not via Tunnel1.
HubA
interface Tunnel0
ip address 10.0.0.1 255.255.255.0
no ip redirects
ip mtu 1400
ip nhrp authentication KEY234
ip nhrp network-id 12345
ip nhrp holdtime 300
ip nhrp redirect
ip tcp adjust-mss 1360
tunnel source GigabitEthernet0/0
tunnel mode gre multipoint
tunnel key 12345
tunnel protection ipsec profile cisco
interface Tunnel1
ip address 10.2.0.1 255.255.255.252
no ip redirects
ip nhrp authentication KEY234
ip nhrp map 10.2.0.2 192.168.0.2
ip nhrp network-id 12345
ip nhrp holdtime 300
ip nhrp redirect
tunnel source GigabitEthernet0/1
tunnel mode gre multipoint
tunnel key 12345
HubB
interface Tunnel0
ip address 10.0.0.2 255.255.255.0
no ip redirects
ip mtu 1400
ip nhrp authentication KEY234
ip nhrp network-id 12345
ip nhrp holdtime 300
ip nhrp redirect
ip tcp adjust-mss 1360
tunnel source GigabitEthernet0/0
tunnel mode gre multipoint
tunnel key 12345
tunnel protection ipsec profile cisco
interface Tunnel1
ip address 10.2.0.2 255.255.255.252
no ip redirects
ip nhrp authentication KEY234
ip nhrp map 10.2.0.1 192.168.0.1
ip nhrp network-id 12345
ip nhrp holdtime 300
ip nhrp redirect
tunnel source GigabitEthernet0/1
tunnel mode gre multipoint
tunnel key 12345
In this setup, the dynamic spoke-to-spoke tunnels won't come up, it seems that the NHRP redirects are not working.
When I establish the BGP neighborship via Tunnel1, it all works fine.
Can you explain, why I have to use the Tunnel1 for BGP neighborship? Do I have any other option to get this working?
