hubÖ
interface Tunnel124
 ip address 172.16.124.1 255.255.255.0
 no ip redirects
 ip mtu 1400
 ip nhrp authentication 124
 ip nhrp map multicast dynamic
 ip nhrp network-id 124
 ip nhrp redirect
 ip tcp adjust-mss 1360
 tunnel source Loopback1
 tunnel mode gre multipoint
 tunnel key 124
end


spoke:
interface Tunnel124
 ip address 172.16.124.2 255.255.255.0
 no ip redirects
 ip mtu 1400
 ip nhrp authentication 124
 ip nhrp map multicast 1.1.1.1
 ip nhrp map 172.16.124.1 1.1.1.1
 ip nhrp network-id 124
 ip nhrp nhs 172.16.124.1
 ip nhrp shortcut
 ip tcp adjust-mss 1360
 tunnel source Loopback1
 tunnel mode gre multipoint
 tunnel key 124