Hi All,
I was reading the design guide for DMVPN and see this config
•Headend router:
!
interface Tunnel0
description dmvpn tunn
ip address 10.173.20.1 255.255.255.0
no ip redirects
ip mtu 1400
ip nhrp authentication secret
ip nhrp network-id 10203
ip ospf network point-to-multipoint
ip ospf hello-interval 30
tunnel source GigabitEthernet0/1.201
tunnel mode gre multipoint
tunnel key 123
tunnel protection ipsec profile dmvpn
!
router ospf 10
network 10.173.20.0 0.0.0.255 area 10
area 10 stub no-summary
!
•Branch router:
!
interface Tunnel0
ip address 10.173.20.21 255.255.255.0
no ip redirects
ip mtu 1400
ip nhrp authentication secret
ip nhrp map multicast dynamic
ip nhrp map 10.173.20.1 192.168.201.1
ip nhrp network-id 10203
ip nhrp nhs 10.173.20.1
ip route-cache flow
ip ospf network point-to-point
ip ospf hello-interval 30
load-interval 30
qos pre-classify
no clns route-cache
tunnel source GigabitEthernet0/0.201
tunnel mode gre multipoint
Could you explain to me what is the reason if we are only allowing hub--spoke communication to make the network type point-2-point and then set the tunnel mode to be gre multipoint?
Also From the ine videos as I understand to allow spoke-2-spoke communication we need to configure the Hub to be the DR and configuring the spokes priotirty to 0 , am I right ? the problem even phase 2 says spoke-2-spoke allowed since we can not advertise neither default nor summary route how spoke-2-spoke will be possible? if it is possible what is the difference between phase2 and phase 3 then in terms of ospf config.