Layer 3 VPN Overview

The JUNOS software implements Layer 3 Border Gateway Protocol/Multiprotocol Label Switching (BGP/MPLS) virtual private networks (VPNs) as defined in Request for Comments (RFC) 2547 and Internet draft BGP/MPLS VPNs, draft-rosen-rfc2547bis (also referred to as RFC 2547bis). This chapter discusses the following topics that provide background information about Layer 3 VPNs:

• Layer 3 VPN Overview
• Layer 3 VPN Standards
• Layer 3 VPN Attributes
• VPN-IPv4 Addresses and Route Distinguishers
• VPN Routing and Forwarding Tables
• Route Distribution within a Layer 3 VPN
• Forwarding across the Provider's Core Network
• Routing Instances for VPNs
• Multicast over Layer 3 VPNs