Border Gateway Protocol. Interdomain routing protocol that exchanges reachability information with other BGP systems. It is defined in RFC 1163.
Cisco Express Forwarding. An advanced Layer 3 IP switching technology. CEF optimizes network performance and scalability for networks with large and dynamic traffic patterns.
Customer Edge Router. A router that is part of a customer network and that interfaces to a provider edge (PE) router.
Class of Service. A feature that provides scalable, differentiated types of service across a tag switched network.
Edge Label Switch Router. The role of an Edge LSR is to turn unlabeled packets into labeled packets. An RPM in the MGX 8850 switch can perform this function. (Formerly referred to as Tag Edge Router [TER].)
Generic Routing Encapsulation. A tunneling protocol developed by Cisco that can encapsulate a wide variety of protocol packet types inside IP tunnels, creating a virtual point-to-point link to Cisco routers at remote points over an IP internetwork. By connecting multiprotocol subnetworks in a single-protocol backbone environment, IP tunneling that uses GRE allows network expansion across a single-protocol backbone environment.
Interior Gateway Protocol. An Internet protocol used to exchange routing information within an autonomous system. Examples of common IGPs include IGRP, OSPF, and RIP.
Intermediate System-to-Intermediate System. OSI link-state hierarchical routing protocol in which ISs (routers) exchange routing information based on a single metric in order to determine network
Label Distribution Protocol. A standard protocol between MPLS enabled routers to negotiate the labels (addresses) used to forward packets. This protocol is not supported in release IOS release 12.0, and therefore is not used for this project. Cisco's proprietary version of this protocol is the TDP (Tag Distribution Protocol).
Label Switch Controller.
The role of an LSC is to create cross connects in an ATM switch so that labelled packets are forwarded through the switch, formerly referred to as Tag Switch Controller, or TSC.
Label virtual circuit
Label Virtual Circuit. Label virtual circuits are used to connect a pair of ATM MPLS devices. The LVCs are established under the direct control of MPLS signalling, and each LVC corresponds to a distinct MPLS label value.
A broadcast packet used by link-state protocols. The LSA contains information about neighbors and path costs and is used by the receiving router to maintain a routing table.
Multiprotocol Label Switching. MPLS forwards IP traffic using a label. This label instructs the routers and switches in the network where to forward the packets based on pre-established IP routing information.
Network Layer Reachability Information. BGP sends routing update messages containing NLRI to describe a route and how to get there. In this context, an NLRI is a prefix. A BGP update message carries one or more NLRI prefixes and the attributes of a route for the NLRI prefixes; the route attributes include a BGP next hop gateway address, community values, and other information.
Provider edge router. A router that is part of a service provider's network and that is connected to a customer edge (CE) router.
Route Distinguisher. An 8-byte value that is concatenated with an IPv4 prefix to create a unique VPN IPv4 prefix.
Routing Information Protocol. Used to exchange routing information within an autonomous system, RIP uses hop count as a routing metric.
Tag Distribution Protocol. Cisco's proprietary version of the LDP. This protocol is used in IOS release 12.0 for label (i.e., "tag") distribution.
Tag-switched Path (TSP)
A sequence of hops (R0...Rn) in which a packet travels from R0 to Rn through MPLS mechanisms. A tag-switched path can be established dynamically, based on normal routing mechanisms, or through configuration.
Tag Switching Router (TSR)
A Layer 3 router that forwards a packet based on the value of a tag encapsulated in the packet.
tag-switched path (TSP) tunnel
A configured connection between two routers, in which MPLS is used to carry the packet.
The techniques and processes used to cause routed traffic to travel through the network on a path other than the one that would have been chosen if standard routing processes had been used.
traffic engineering tunnel
A tag-switched path tunnel that is used for engineering traffic. It is set up through means other than normal Layer 3 routing and is used to direct traffic over a path different from the one that Layer 3 routing would cause it to take.
Architecture providing the services necessary to implement any standard point-to-point data encapsulation scheme.
A portion of a physical interface that has the following characteristics: Address space containing only one VPI and all VCIs underneath, bandwidth that is rate limited by hardware (VI), and ownership by a controller that uses it to interface to another peer controller.
Virtual private network. A secure IP-based network that shares resources with one or more physical networks. A VPN can contain one or more geographically dispersed sites that can communicate securely over a shared backbone.
Used as a keyword in commands to indicate VPN-IPv4 prefixes. These prefixes are customer VPN addresses, each of which has been made unique by the addition of an 8-byte route distinguisher.
Virtual Switch Interface. A protocol that allows for a common control interface to some of Cisco's ATM switches, for example, the MGX 8850 and BPX products.
A VPN routing/forwarding instance. A VRF consists of an IP routing table, a derived forwarding table, a set of interfaces that use the forwarding table, and a set of rules and routing protocols that determine what goes into the forwarding table. In general, a VRF includes the routing information that defines a customer VPN site that is attached to a PE router.