Download - Leased Line (MLLN)

7/29/2019 Leased Line (MLLN)

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Leased Line Data Circuits


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Leased Lines

Dedicated pair of copper wires for 24 hour data

service provision to customers.

It is a physical path owned by the user or rented outby the provider.


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Types

Conventional leased line

Managed leased line network (MLLN)


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Conventional Leased Line

This technology marked the beginning of the use of

leased line technology for data transmission.

Conventional leased lines are very rarely used now.


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Managed Leased Line Network

BSNL uses Tellabs 8100 system in providing MLLN. This system is describedas follows.

The MLLN is a Managed Leased Line Network system, which can provideleased line connectivity.

MLLN is capable of supporting two type of leased line.

1. Point to Point Circuit

2. Point to Multi Point Circuit

Bandwidth of a Managed Leased Line can be 64Kbps to n x 64 Kbpswhere n = 1,2,3,32.


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MLLN applications

Corporate hi--speed Internet Access through NIB

Point to Multipoint Connection for data circuit

Point to Point Connection for data circuit

Hotline connectivity for voice

LAN-Inter Connection

EPABX Inter--connection

Virtual Private Network on MLLN Network

Extension of VPN (MPLS) to customer through MLLN


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STRUCTURE OF MLLNThe MLLN is planned as threetier structure

A Central Node provide following functions:

NMS Centre.

Connectivity to second stage Nodes.

Second stage Node : It is located at major cities of a

Telecom Circle, where demand for leased line is high.

Third Stage Node : It is located at smaller cities/ towns of a

Telecom circle where demand for leased line is lower.


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MLLN NODES

A Node can be described as a digital Multiplexerequipped with several trunk interfaces & as a

digital cross connect device equipped with

several channel interfaces.

DXC (Digital cross connect)

VMUX (Versatile Multiplexer)

NTU (Network Terminating Unit) NMS (Network Management system)


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MLLN STRUCTURE


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Network Termination Unit (NTU)

As the name suggests, NTUs are basically termination units for

the MLLN system. It is the equipment which is located within

the user premises.

A copper twin connects the NTUs to the respective VMUX (the

OMH card of the VMUX).

BSNL provides subscribers with a number of NTU versions, butthe two most prominent ones are Tellabs 8110 CTU-S and

Tellabs 8110 CTU-R.


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VMUX(8150 node)

Tellabs 8150 basic node is the basic building blockof the Tellabs 8100 system.

VMUX is a small capacity cross connect device & is

installed at different sites for providing user

connectivity.

It is used in local exchange or backbone networks

or customer premises networks, depending on the

needed services & applications.


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Tellabs 8150


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VMUX Card Description

OMH (Octet Module Housing): The copper twin from thesubscribers reaches the MDF (Main Distribution Frame) and

then from that the line is terminated at the OMH card. The

number of OMH cards depends on the user density. Each card

consists of four ports each port terminating two subscriberlines.

QMH (Quadrat Module Housing) and XCG (Cross Connect

Group): The OMH is connected to the QMH and the XCG from

which the multiplexed-demultiplexed output is sent to the

slave rack of a DXC. The QMH and XCG cards have four ports,

each port housing one E1 links.


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Digital Cross Connect (DXC)

DXCs at Metros are designated as Regional DXCs (R-DXC).

DXCs at different maintenance regions apart from metros are

called Sub-regional DXCs (SR- DXC)

DXCs in the SSAs (Secondary Switching Area) level are called

SS-DXC.

A DXC (Digital X-Connection) is equipped with several trunk

(E1) interfaces coming from other DXCs or VMUXs.


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RDXC DELHIRDXC

KOLKATA

RDXC

MUMBAIRDXC

CHENNAI

SRDXC

SSADXC

E1

E1

VMUXSRDXC

SSADXC

VMUXNTU

NTU

A Office at Mumbai is having a leased line connection with another branch office atKolkata


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Thank You