Why BGP MPLS VPNs?

"Why do we need VPNs?"

We need VPNs because enterprises need private connectivity, and they need that over a shared infrastructure to minimize their costs.

"Why do we need MPLS?"

This is because MPLS offers a good infrastructure for converged networks. Rather than using passwords, it offers hierarchy, data privacy, traffic engineering, and differentiated services.

"Why do we need BGP?"

We need BGP because it offers a common framework for providing all VPN types--Layer 2 VPNs, IP VPNs, and VPLS. In addition, it can do auto-discovery, VPN label exchange, and interprovider and carrier-to-carrier VPNs.

Why do we need all these kinds of VPNs?

We need Layer 2 VPNs because of their legacy; they are there and have been for a long time.
We need IP VPNs because traffic is increasingly all IP, and any-to-any connectivity has its benefits. Moreover, outsourcing routing can be a big cost saver.And we need VPLS, as this is an exciting new service that takes advantage of an exciting new medium, Ethernet.