Glossary of Terms

L

LAN
Local Area Network. A data communication network covering a relatively small area, typically a building, that runs at moderate to high data rates.

LAN telephony
The convergence of voice and data on a LAN eliminating the need for seperate voice and data networks with an organisation.

LAP
Link Access Protocol. ITU family of HDLC based error correction protocols.

LAPM
Link Access Procedure for Modems (per Recommendation V.42).

LCR
Least Cost Routing. The PBX uses the LCR (Least Cost Routing) function to control automatically the path over which the outgoing connection is routed. The connection can be made via public network (fixed line) or alternative network operators (providers/carriers). This ensures that the most cost-effective connection for the customer is used.

Line and trunk gateways
These elements provide connectivity to the public network (either the local line or long-haul trunking segments, respectively)

LLU
Local loop unbundling. As part of the deregulation of European Telecommunications, incumbent operators (e.g. BT in the UK), are now obliged to allow other licenced telecommunications operators (e.g. Easynet) to access the local loop infrastructure (A.K.A. Metallic Path Facilities) and provide their own access and value-added services. This involves the operator locating its own transmission equipment at specific BT exchange locations for a fixed 'co-location' fee.

Local loop
The copper pair of wires that connects the customer from their network terminating point (NTP or NTU) to the local BT telephone exchange.