- Phase 1 DMVPN uses point-to-point GRE tunnel on spoke routers and multipoint GRE tunnel on the hub router.
- All the DMVPN traffic (including the traffic between the spokes) flows through the hub router.
- On the spoke routers, the hub router must be the IP next-hop for all destinations reachable through the DMVPN subnet (including other spokes).
- Multicast packets (including routing protocol hello packets and routing updates) are exchanged only between the hub and the spoke routers.
- Basic hub router configuration;
- Explanation of GRE tunnel key concept and its potential performance implications;
- NHRP configuration of the hub and spoke routers;
- Non-unique NHRP registrations;
- Multicast over mGRE principles;
- DMVPN redundancy;
- IPSec configuration with shared keys and certificates;
- Monitoring and troubleshooting guidelines.