Which type of VPN implementation is simple and cost effective because all sites connect only to the PE router and as a result optimum routing between sites is enabled by default?
A.
peer-to-peer VPN
B.
overlapping VPN
C.
hub-and-spoke overlay VPN
D.
fully-meshed overlap VPN
E.
client-server VPN
Explanation:
The first peer-to-peer VPN solution appeared with the widespread deployment of IP in service provider networks. Architectures similar to that of the Internet were used to build them. Special provisions were taken into account to transform the architecture, which was targeted toward public backbones (Internet), into a solution in which customers would be totally isolated and able to exchange corporate data securely. The more common peer-to-peer VPN implementation allowed a PE router to be shared between two or more customers. Pachet filters were used on the shared PE routers to isolate the customers. In this implementation, it was common for the service provider to allocate a portion of its address space to each customer and manage the packet filters on the PE routers to ensure full reachability between sites of a single customer and isolation between separate customers.
Reference: Cisco Press – Implementing Cisco MPLS study guide p.4-23