Understanding Types of Models in VPN?

VPN Services are mainly divided into two models

i) Overlay Model :

--> Service Provider provides virtual connection between customer site.

--> For each customer site, one virtual connection is created.

--> Service Provider does not participate in customer routing.

--> Well Known and easy to implement.

--> Customer Network and Service Provider network are completely isolated.

---> Ex: Frame-Relay,ATM,X.25,GRE,IPSEC,DMVPN,SSLVPN

2) Peer-Peer Model:

--> Service Provider Provides layer 3 connection for each site.

--> For all customer sites, there is only one logical connection is created in service provider network.

--> Service Provider participates in customer routing.

--> Easy to add new customer sites compared to overlay model.

--> Ex: MPLS,GETVPN