bundled interface —Generic terms to represent port-channel, multilink, and VLAN interfaces.

Cisco express forwarding —A means for accelerating the forwarding of packets within a router, by storing route lookup information in several data structures instead of in a route cache.

CLNS —Connectionless Network Service. The Open Systems Interconnection (OSI) network layer service that does not require a circuit to be established before data is transmitted. CLNS routes messages to their destination independently of any other messages.

CSPF —Constrained Shortest Path First. A routing protocol that calculates the shortest path based on a set of constraints, such as a minimum bandwidth requirement, maximum number of nodes, or nodes to include or exclude.

enterprise network —A large and diverse network connecting most major points in a company or other organization.

FRR —Fast ReRoute.

headend —The endpoint of a broadband network. All stations send toward the headend; the headend then sends toward the destination stations.

IGP —Interior Gateway Protocol. An Internet protocol used to exchange routing information within an autonomous system. Examples of common Internet IGPs include Interior Gateway Routing protocol (IGRP), Open Shortest Path First (OSPF), and Routing Information Protocol (RIP).

interface —A network connection.

IS-IS —Intermediate System to Intermediate System. OSI link-state hierarchical routing protocol based on DECnet Phase V routing, where ISs (routers) exchange routing information based on a single metric, to determine the network topology.

LDN — Link Down Notification.

LSP —Label-Switched Path. A sequence of hops (R0...Rn) in which a packet travels from R0 to Rn through label switching mechanisms. A label-switched path can be chosen dynamically, based on normal routing mechanisms, or through configuration.

member links —Individual interfaces that are grouped into a bundled interface.

message-pacing —The former name of the rate limiting feature.

MPLS —Formerly known as tag switching, Multiprotocol Label Switching is a method for directing packets primarily through Layer 2 switching rather than Layer 3 routing. In MPLS, packets are assigned short fixed-length labels at the ingress to an MPLS cloud by using the concept of forwarding equivalence classes. Within the MPLS domain, the labels are used to make forwarding decisions mostly without recourse to the original packet headers.

OSPF —Open Shortest Path First. A link-state, hierarchical Interior Gateway Protocol (IGP) routing protocol. derived from the Intermediate System-Intermediate System (IS-IS) protocol. OSPF features are least-cost routing, multipath routing, and load balancing.

router —A network layer device that uses one or more metrics to determine the optimal path along which network traffic should be forwarded. Routers forward packets from one network to another based on network layer information.

RSVP —Resource Reservation Protocol. A protocol that supports the reservation of resources across an IP network.

scalability —An indicator showing how quickly some measure of resource usage increases as a network gets larger.

TLV —type, length, value. TLV objects are used in data communication to provide optional information. The type field indicates the type of items in the value field. The length field indicates the length of the value field. The value field is the data portion of the packet.

topology —The physical arrangement of network nodes and media within an enterprise networking structure.

TE (traffic engineering) —Techniques and processes that cause routed traffic to travel through the network on a path other than the one that would have been chosen if standard routing methods were used.

traffic engineering tunnel —A label-switched tunnel that is used for traffic engineering. Such a tunnel is set up through means other than normal Layer 3 routing; it is used to direct traffic over a path different from the one that Layer 3 routing would cause the tunnel to take.