Which type of overlay VPN is simplest to implement?

A.
Fully-meshed

B.
Hub-and-spoke

C.
Partial-mesh

D.
Redundant hub-and-spoke

Explanation:

This type requires the least number of vpn connections and the routing is so simple that you don’t even need to run a routing protocol (though it would simplify your daily administration..)
The hub-and spoke topology is the simplest overlay VPN topology – all sites are linked with a single virtual circuit to a central CE router. The routing is also extremely simple-static routing or a distance vector protocol such as Routing Information Protocol (RIP) is more than adequate. If a dynamic routing protocol such as RIP is used, split-horizon updates must be disabled at the hub router or point-to-point subinterfaces must be used at the hub router to overcome the split-horizon problem. Reference: Cisco Press – Implementing Cisco MPLS study guide p.4-36