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?

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.

Cisco Press – Implementing Cisco MPLS study guide p.4-23