| ATM | Asynchronous Transfer Mode - The international standard for cell relay in which multiple 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. |
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| CHAP | Challenge Handshake Authentication Protocol - Security feature supported on lines using PPP encapsulation that prevents unauthorized access. CHAP does not itself prevent unauthorized access, but merely identifies the remote end. The router or access server then determines whether that user is allowed access. |
| DSLAM | Digital Subscriber Line Access Multiplexer - A device that connects many digital subscriber lines to a network by multiplexing the DSL traffic onto one or more network trunk lines. |
| L2TP | Layer 2 Tunneling Protocol [More Info] |
| LAC | L2TP Access Concentrator - A node that acts as one side of an L2TP tunnel endpoint and is a peer to the L2TP network server (LNS). The LAC sits between an LNS and a remote system and forwards packets to and from each. |
| LCP | Link Control Protocol - Protocol that establishes, configures, and tests data-link connections for use by PPP. |
| LNS | L2TP Network Server - A node that acts as one side of an L2TP tunnel endpoint and is a peer to the L2TP access concentrator (LAC). The LNS is the logical termination point of a PPP session that is being tunneled from the remote system by the LAC. |
| LSS | Limited Service Selection Enables users to connect to up to five home gateways. e.g. - enabling teleworkers to have one connection for corporate LAN access and a second connection for normal Internet access. It is not possible to have simultaneous connections to different home gateways - only one connection is permitted at any given time. |
| Mbps | Mega bits per second |
| Multiplexer | Equipment that enables several data streams to be sent over a single physical line. Also referred to as mux. |
| PPP | Point to Point Protocol - Successor to SLIP that
provides router-to-router and host-to-network connections over
synchronous and asynchronous circuits. Whereas SLIP was designed to work
with IP, PPP was designed to work with several network layer protocols,
such as IP, IPX, and ARA. PPP also has built-in security mechanisms,
such as CHAP and PAP. |
| PSTN | Public Switched Telephone Network |
| PVC | Permanent Virtual Circuit/Connection - Virtual circuit that is permanently established. PVCs save bandwidth associated with circuit establishment and tear down in situations where certain virtual circuits must exist all the time. In ATM terminology, this is called a permanent virtual connection. |
| RADIUS | Remote Authentication Dial-In User Service - Database for authenticating modem and ISDN connections and for tracking connection time. Used in the UK ADSL system for authenticating and routing users to the correct gateway. |
| SSB | Service Selection Barring The system used by BT Wholesale to control which usernames a user can use on their particular line. Without SSB any user could log onto any ISP if they had the username/password. SSB is intended to improve security and to allow BT Wholesale to control the contention ratios at various points in their network. Problems logging into your ISP can occur if incorrect account details are entered into the database. The time taken to fix this is very variable. |
| Tunnel | Secure communication path between two peers. eg - two routers. |
| VP | Virtual Path - A bundle of virtual channels, all of which are switched transparently across an ATM network. |
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