Will MPLS replace Frame Relay or ATM as the VPN technology of choice?

·         Layer 2 or Layer 3 MPLS VPN can run on frame relay, ATM infrastructure. A common choice of technology for the service provider’s core network is SONET/SDH.
·         Layer 2 MPLS VPNs allow service providers full freedom to choose internal network technologies independent of the Layer 2 VPN service offerings.
·         Currently most VPN networks are based on MPLS technology. Customer prefer MPLS VPN because of its flexibility, scalability and multilevel protection offered by IP network.