This section defines acronyms and words that may not be readily understood.
AS --Autonomous System. A collection of networks under a common administration, sharing a common routing strategy and identified by a unique 16-bit number (assigned by the Internet Assigned Numbers Authority).
ATM --Asynchronous Transfer Mode. The international standard for cell relay in which several service types (such as voice, video or data) are conveyed in fixed-length (53-byte) cells. Fixed-length cells allow cell processing to occur in hardware, thereby reducing transit delays. ATM is designed to take advantage of high-speed transmission media, such as E3, SONET, and T3.
BGP --Border Gateway Protocol. The predominant interdomain routing protocol. It is defined by RFC 1163. Version 4 uses route aggregation mechanisms to reduce the size of routing tables.
BPX --A Cisco standards-based ATM switch that supports broadband, narrowband, and IP services.
CBR--Constraint Based Routing. The computation of traffic paths that simultaneously satisfy label-switched path attributes and current network resource limitations.
CEF --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.
CLI--Command Line Interface. Cisco's interface for configuring and managing its routers.
DS-TE --Diff Serv-aware Traffic Engineering. The capability to configure two bandwidth pools on each link, a global pool and a sub-pool. MPLS traffic engineering tunnels using the sub-pool bandwidth can be configured with Quality of Service mechanisms to deliver guaranteed bandwidth services end-to-end across the network. Simultaneously, tunnels using the global pool can convey diff-serv traffic.
flooding --A traffic passing technique used by switches and bridges in which traffic received on an interface is sent out through all of the interfaces of that device except the interface on which the information was originally received.
GB queue --Guaranteed Bandwidth queue. A per-hop behavior (PHB) used exclusively by the strict guarantee traffic. If delay/jitter guarantees are sought, the diffserv Expedited Forwarding queue (EF PHB) is used. If only bandwidth guarantees are sought, the diffserv Assured Forwarding PHB (AF PHB) is used.
Global Pool --The total bandwidth allocated to an MPLS traffic engineering link.
IGP --Interior Gateway Protocol. An internet protocol used to exchange routing information within an autonomous system. Examples of common internet IGPs include IGRP, OSPF, and RIP.
label-switched path (LSP) tunnel --A configured connection between two routers, using label switching to carry the packets.
IS-IS --Intermediate System-to-Intermediate System. A link-state hierarchical routing protocol, based on DECnet Phase V routing, whereby nodes exchange routing information based on a single metric, to determine network topology.
LCAC --Link-level (per-hop) call admission control.
LC-ATM --Label switching Controlled ATM. The assignment of values into the VPI/VCI field of ATM cells by MPLS rather than by ATM control procedures.
LSP --Label-switched path (see above).Also Link-state packet--A broadcast packet used by link-state protocols that contains information about neighbors and path costs. LSPs are used by the receiving routers to maintain their routing tables. Also called link-state advertisement (LSA).
MPLS --Multi-Protocol Label Switching (formerly known as Tag Switching). A method for directing packets primarily through Layer 2 switching rather than Layer 3 routing, by assigning the packets short fixed-length labels at the ingress to an MPLS cloud, 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.
MPLS TE --MPLS Traffic Engineering (formerly known as "RRR" or Resource Reservation Routing). The use of label switching to improve traffic performance along with an efficient use of network resources.
OSPF --Open Shortest Path First. A link-state, hierarchical IGP routing algorithm, derived from the IS-IS protocol. OSPF features include least-cost routing, multipath routing, and load balancing.
POS --Packet over SONET (Synchronous Optical Network).
PVC --Permanent Virtual Connection. A circuit or channel through an ATM network provisioned by a carrier between two end points; used for dedicated long-term information transport between locations. PVCs save bandwidth associated with circuit establishment and tear down in situations where certain virtual circuits must exist all the time.
RSVP --Resource reSerVation Protocol. An IETF protocol used for signaling requests (to set aside internet services) by a customer before that customer is permitted to transmit data over that portion of the network.
Sub-pool --The more restrictive bandwidth in an MPLS traffic engineering link. The sub-pool is a portion of the link's overall global pool bandwidth.
TE --Traffic engineering. The application of scientific principles and technology to measure, model, and control internet traffic in order to simultaneously optimize traffic performance and network resource utilization.