DMVPN Phase 1 Hub & Spoke – OSPF example
Technology: WAN
Area: DMVPN
Vendor: Cisco
Software: 12.X , 15.X ISR
Platform: ISR 1800, 2800, 3800, 1900, 2900, 3900, Platforms: 4300, 4400
Traffic Flow:
- Packet is sent from Spoke1 to Spoke2 network via Hub (according to routing table)
- Spoke1 has this prefix via HUB tunnel IP for which has also NHRP static mapping
- Hub routes packet to Spoke2 according to routing table via tunnel
DMVPN Phase 1 and OSPF
- Configure OSPF point to multipoint network type (next hop behavior)
- Advertise spoke’s connected routes
- Set static default routes on spokes into HUB direction via tunnel interface
HUB:
!
!
router ospf 1
router-id 20.1.1.1
network 20.1.1.0 0.0.0.255 area 0
network 172.16.1.0 0.0.0.255 area 0
!
! Tunnel source
!
interface Loopback0
ip address 30.159.1.1 255.255.255.0
!
! VPN network
!
interface Loopback 1
ip address 20.1.1.1 255.255.255.0
!
! mGRE tunnel
!
interface Tunnel0
ip address 172.16.1.1 255.255.255.0
no ip redirects
ip nhrp authentication AVI@OLU
ip nhrp map multicast dynamic
ip nhrp network-id 111
tunnel source Loopback0
tunnel mode gre multipoint
tunnel key 123
ip ospf network point-to-multipoint
NOTE : Mirror below Spokes configuration on Spoke B with its respective IP details.
Spoke A:
!
!
router ospf 1
router-id 20.1.2.2
network 20.1.2.0 0.0.0.255 area 0
network 172.16.1.0 0.0.0.255 area 0
!
interface Loopback0
ip address 30.159.2.2 255.255.255.0
!
interface Loopback 1
ip address 20.1.2.2 255.255.255.0
!
! GRE tunnel
!
interface Tunnel0
ip address 172.16.1.2 255.255.255.0
ip nhrp authentication AVI@OLU
ip nhrp map 172.16.1.1 30.159.1.1
ip nhrp map multicast 30.159.1.1
ip nhrp nhs 172.16.1.1
ip nhrp network-id 111
ip nhrp holdtime 60
ip nhrp registration timeout 30
tunnel source Loopback0
tunnel destination 30.159.1.1
tunnel key 123
ip ospf network point-to-multipoint
