A Layer 3 VPN provides routed, IP-based connectivity to customers across a provider's shared backbone. The term IP-VPN is a generic industry name for this service. The most prevalent technology for implementing this is BGP/MPLS VPN, as standardized in IETF RFC 4364, which uses Multiprotocol BGP to distribute customer routes. VPRN (Virtual Private Routed Network) is the specific term used by Nokia to describe its Layer 3 VPN service implementation on its Service Router platforms. All three terms correctly describe a Layer 3 VPN service from different perspectives (generic, technological, and vendor-specific).

C. VLL: Virtual Leased Line (VLL) is a point-to-point Layer 2 VPN service that emulates a private line, not a routed Layer 3 network.

D. VPLS: Virtual Private LAN Service (VPLS) is a multipoint Layer 2 VPN service that emulates an Ethernet LAN segment across a WAN.

F. ePipe: This is Nokia's specific product name for a point-to-point Ethernet VLL (a Layer 2 service), not a Layer 3 VPN.

1. Nokia 7750 SR OS Services Guide, Release 21.10.R1: In the "VPRN Services" chapter, the introduction states, "A Virtual Private Routed Network (VPRN) is a Layer 3 virtual private network (VPN) service that consists of a set of customer sites connected to a common IP/MPLS service provider network." This directly links VPRN to Layer 3 VPNs. The same guide defines VPLS and ePipe services as Layer 2 VPNs in their respective chapters.

2. Rosen, E., & Rekhter, Y. (2006). BGP/MPLS IP Virtual Private Networks (VPNs). RFC 4364. Internet Engineering Task Force (IETF). The title and abstract of this foundational document explicitly define the "BGP/MPLS IP VPN" architecture. The abstract states, "This document describes a method by which a Service Provider may use an IP backbone to provide IP Virtual Private Networks (VPNs) for its customers." This confirms that BGP/MPLS VPN and IP-VPN refer to the same Layer 3 service. (DOI: https://doi.org/10.17487/RFC4364)