BGP --Border Gateway Protocol. An interdomain routing protocol that replaces Exterior Gateway Protocol (EGP). A BGP system exchanges reachability information with other BGP systems. BGP is defined by RFC 1163.
BGP/MPLS/VPN --A Virtual Private Network (VPN) solution that uses Multiprotocol Label Switching (MPLS) and Border Gateway Protocol (BGP) to allow multiple remote customer sites to be connected over an IP backbone. Refer to RFC 2547 for details.
CE router --A customer edge router. A router that is part of a customer network and interfaces to a provider edge (PE) router.
customer network --A network that is under the control of an end customer. A customer network can use private addresses as defined in RFC 1918. Customer networks are logically isolated from each other and from the provider network. A customer network is also known as a C network.
egress PE --The provider edge router through which traffic moves from the backbone to the destination Virtual Private Network (VPN) site.
flow --A set of packets with the same source IP address, destination IP address, source/destination ports, and type-of-service, and the same interface on which flow is monitored. Ingress flows are associated with the input interface, and egress flows are associated with the output interface.
ingress PE --The provider edge router through which traffic enters the backbone (provider network) from a Virtual Private Network (VPN) site.
label --A short, fixed length identifier that tells switching nodes how the data (packets or cells) should be forwarded.
MPLS --Multiprotocol Label Switching. An emerging industry standard for the forwarding of packets along normally routed paths (sometimes called MPLS hop-by-hop forwarding).
PE route r--A provider edge router. A router at the edge of a provider network that interfaces to customer edge (CE) routers.
provider network --A backbone network that is under the control of a service provider and provides transport among customer sites. A provider network is also known as the P network.
VPN --Virtual Private Network. The result of a router configuration that enables IP traffic to use tunneling to travel securely over a public TCP/IP network.
VRF --Virtual Private Network (VPN) routing/forwarding instance. The VRF is a key element in the MPLS VPN technology. VRFs exist on PEs only. A VRF is populated with VPN routes and allows one PE to have multiple routing tables. One VRF is required per VPN on each PE in the VPN.