Introduction

Leased line is a permanent telephone connection between two points set up by a telecommunications common carrier. Typically, leased lines are used by businesses to connect geographically distant offices. Charges are fixed and are not dependent on usage frequency. This will be very cost effective for constant bulk transmission of data and information. This guideline document will help the NOC engineers to understand to configure and trouble shoot Leased lines. It also gives details on the process to be followed for commissioning and de-commissioning leased lines.

PURPOSE OF LEASED LINE

Unlike dial-up connections, a leased line is always active (i.e., a end to end dedicated connection). As the connection is a dedicated one, it will not carry anybody else's traffic. This will assure security and a given level of quality.

TYPES OF CIRCUITS

2-WIRE Circuit

As the name implies, this type of Leased lines will be built on a single pair of wire (i.e., 2 wires). It works in half duplex mode (at any point of time the traffic will be flowing in a single direction). It supports up to a maximum of 2Mbps.

4-WIRE Circuit

As the name implies, this type of Leased lines will be built on a two pairs of wires (i.e., 4 wires). It works in full duplex mode in which one pair is used for transmission and remaining pair is used for reception (at any point of time the traffic will be flowing in both directions). It supports up to a maximum of 2Mbps.

MLLN (Managed Leased Line Network)

Managed Leased Line Network (MLLN) is the data network concept that provides fully secure data communication services over Managed Leased Lines which will be managed by the Basic Service Operators (BSO). It is a system by which corporate offices and business establishments can establish a truly private communication network for the purpose of transmitting and receiving information from one location to another. The media available for use by MLLN are fiber-optic lines, microwave transmission systems, satellite transmission systems, coaxial cable systems and copper lines. The specialty of MLLN is given below.

1. MLLN has greater quality and intensity.
2. Need based bandwidth
3. Time based bandwidth
4. Confidentiality is assured