This document provides requirements for Layer 3 Virtual Private Networks (L3VPNs). It identifies requirements applicable to a number of individual approaches that a Service Provider may use to provision a Virtual Private Network (VPN) service. This document expresses a service provider perspective, based upon past experience with IP- based service offerings and the ever-evolving needs of the customers of such services. Toward this end, it first defines terminology and states general requirements. Detailed requirements are expressed from a customer perspective as well as that of a service provider.