SECTION 3.

6
MLLN- MANAGED LEASED LINE NETWORK
 Section 3.6

MLLN – MANAGED LEASED LINE NETWORK

The MLLN service is specially designed mainly for having effective control and
monitoring on the leased line so that the down time is minimized and the circuit efficiency is
increased. This mainly deals with data circuits ranging from 64 Kbps to 2048 Kbps.

1.0 DRAWBACK OF TRADITIONAL LEASED LINE CIRCUITS

1. Limited range of services - Only Plain Leased Line Service, Data cards support only
up to 64 kbps, no support for N x 64 Kbps.

2. From Operator pointt of view in case of Leased Line Circuit different boxes from
different vendors so difficult to manage & control.

3. No Centralized Monitoring or alarm or performance monitering.

Therefore we should have a control to all this, we are able to identify before the customer
know which circuit has gone faulty The solution to this is MLLN

2.0 MLLN FEATURES:

1. MLLN is an integrated, fully managed , multi service digital network platform through
which service provider can offer a wide range of service at an optimal cost to business
subscriber.

2. Using NMS, MLLN can provide high speed Leased Line with improved QoS, high
availability & reliability.

3. Except for connecting the local lead to the MODEM all operations & maintenance is
carried out through ROT (Remote Operating Terminal)

 242 ROT upto 2003 and 178 new ROT installed after 2003

4. NMS supports service provisioning, Network optimization, planning & service

monitering.

5. System offers end to end circuit creation and modification, circuit loop testing & fault
isolation, automatic rerouting of traffic in case of trunk failure, software
programmability of NTU etc.

6. Banking, Financial institution, Stock market, paper industry, broadcasting & Internet
service Provider main customers for MLLN.

3.0 MLLN ADVANTAGES:

1. 24 hrs Performance Monitering of the circuit. (how much time circuit time up & down
and the reason for down time e.g MODEM switch off or other reason)

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 Section 3.6

2. Circuit fault reports generated proactively.(Before customer know we should detect the
fault & rectify it)

3. On Demand the Bandwidth can be increased. (without changing the MODEM recreate
the circuit with the same MODEM)

4. Low lead time for new circuit provisioning. (Create & debug if any fault)

5. Protection against the failure of the circuit (through recovery Management process either
automatic or manually)

6. Long drive on single copper pair.( for 64 kbps – 7 kms & for 2mbps – 3.5 kms)

7. Centrally managed from ROT connected to the NMS

4.0 APPLICATION OF MLLN:

1. Corporate high speed internet access through Broadband.

2. LAN interconnection.

3. Hotline connectivity for voice.

4. Point to point connection for data circuit.

5. point to multipoint connection.

6. EPABX Interconnection.

7. VPN on MLLN Network.

8. Extension of VPN (MPLS) to Customer.

5.0 KEY ELEMENTS OF MLLN:

 MLLN Nodes

 Servers

 Workstations

 Networking Equipment

 Others (Printers, UPS etc)

5.1 MLLN Nodes

o DXC (Digital Cross-Connect)

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 Section 3.6

o VMUX (Versatile Multiplexer)

o NTU (Network Terminating Unit)

o NMS (Network Management System)

5.2 SERVERS

o Database Server

o NMS Application Servers

o Billing and Accounting Servers

o Web Self Care Servers

o Proxy Servers

5.3 WORKSTATIONS

o Local Operator Terminals

o Remote Operator Terminals

5.4 NETWORKING EQUIPMENT

o Router

o LAN Switch

o RAS

o Firewall

o Remote Operator Terminal Connectivity Equipment

o Grooming Mux at Main and DR Sites

o Connectivity equipments at Remote Sites

5.5 Others

o Un-interrupted power supply

o Printers

o Messaging System

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 Section 3.6

6.0 NETWORK ARCHITECTURE:

Main DXC
256 Ports

DXC-64 DXC-64 DXC-128

VMUXs

Modems

Fig. 1 Network Architecture of MLLN

6.1 DXC

Capacity

 DXC (64 ports upgradeable to 128 ports)

 DXC (96 ports upgradeable to 128 ports)

 DXC (128 ports upgradeable to 256 ports)

 DXC (256 ports)

1/0 cross-connect capability

Non-Blocking Architecture

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 Section 3.6

Redundancy

 Power Supply

 Switching Matrix

 Cross-connect Memory

Expansion to be made possible by addition of cards only.

Fully Managed from Centralized NMS

6.2 VMUX

Type - I, Type - II, Type - III with the configurations given below

64 kbps N*64 kbps E1 Links

VMUX Type I 32 8 12

VMUX Type II 16 4 4

VMUX Type III 8 4 4

Expansion to be made possible on the same chassis by addition of cards

Type III VMUX

> 230V AC Powered

> -48V DC Powered

VMUX to be able to extend hotline circuits

> Point to point and Point to Multi-point circuit routing should be possible

HDSL Driving Distance:

> 3.5km at 2Mbps

> 5 km at 1Mbps

> 7km for 64/128kbps (at 0.5mm dia copper cable

6.3 NTU (Network Terminating Unit)

Capacity

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 Section 3.6

> 64/128kbps NTU with V.35

> 64/128kbps NTU with G.703

> N x 64kbps NTU with V.35

> N x 64kbps NTU with G.703

> N x 64kbps NTU with Ethernet Interface

Line Loop Testing as per ITU-T Rec V.54

64kbps NTU to work up to 128kbps

N x 64kbps NTU to work up to 2Mbps

NTU to send power off signal to the NMS at the time of NTU getting switched off.

STU-160 works up to 128kbps

CTU-S and CTU-R works up to 2Mbps on a single pair of copper

All NTU’s support V.54 line loop testing and support dying gasp to send power off signal at time
of power off condition.

6.4 NMS (Network Management System)

o MLLN NMS

o Billing and Accounting System

o Web Self-care system

o We have offered Tellabs Network Manager Release 13 to meet the requirements

o MLLN NMS performs all the management functions on the network

o Supports regional partitioning and VPN capabilities

o Offered Performance Monitoring, Recovery, Reporting Packages

o Offered HP Open view and Cisco works which would reside on SNMP server for
managing the servers and IT elements

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 Section 3.6

7.0 NETWORK PLAN :

Fig. 2 Network Plan of Training centers

8.0 Different Nodes Used in MLLN

A node can be described as a digital multiplexer equipped with several trunk interfaces
and as a digital cross-connect device equipped with several channel interfaces.

The cluster node is used in the network as a high capacity cross-connection device with several
subracks. The basic nodes and midi nodes are used as flexible multiplexers or medium capacity
cross-connect equipment. They have both one subrack.

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 Section 3.6

The basic nodes or midi nodes are used if customer access to the network requires a lot of
tributary port capacity. A basic node can also be used as a cross-connect device in the network
(on consolidation level). A midi node is usually used as an access multiplexer. mini nodes are
used as access multiplexers or low capacity cross-connect equipment. micro nodes are used as
small capacity cross-connection devices especially in mobile networks. network terminating
units (NTUs) are used on customer premises. The accelerator node A111 combines PDH and
SDH technologies to form a solution for interfacing customer access to backbone transport. The
accelerator node A111 is an SDH access multiplexer with one or two 155 Mbit/s STM-1
aggregate electrical or optical interfaces.

8.1 Cluster Node:-

It is built in Master-slave architecture. The cluster node represents the largest node of the
System. It is built in master-slave architecture. It consists of a master sub rack and 1 - 8 slave sub
racks. Slave sub racks can be either double (32 unit slots), single (16 unit slots) or midi (8 unit
slots) sub racks.

The maximum cross-connect port capacity of a cluster node is

8 * 64 Mbit/s = 512 Mbit/s = 256 * 2048 kbit/s port = 64 * 8448 kbit/s port. Each slave sub rack
brings 64 Mbit/s to the cross-connect port capacity. The cluster node can be expanded without
disturbing the existing traffic. The cluster node cross-connects at TS (64 kbit/s) level. The cluster
node’s master subrack is mechanically similar to the double subrack in the basic node. The
difference is that the motherboard and bus extender cards are different.

8.2 Basic Node:-

The Basic Node is the basic building block of the system. (16 unit slot). It is used in local
exchange or backbone networks or customer premises networks, depending on the needed
services and application. The cross connect port capacity of a Basic node is 64 Mbps = 32*2048
kbps port = 8*8448 kbps port

8.3 Midi Node:-

It is a small size flexible access node for customer premises. Midi node has the same
cross-connect functionality as the basic node (64 Mbps) One slot wide multifunctional interface
unit XCG designed for the Midi node. Midi node supports mainly the same interface units as the
basic node.

8.4 Mini Node:-

The mini node is a small cross-connect device, which can operate as either part of the
network connected to the network manager or as a separate cross-connect device controlled and
supervised locally. The mini node is functionally very close to the basic node. The main
difference is that in the mini node the common units (Control Unit, Cross-connection Unit and
Power Supply Unit) are integrated to the node.

The cross-connect port capacity of a mini node is 64 Mbit/s. It supports 2-4 interface
modules with 1, 2, 5 or 10 interfaces each. Due to this limitation of the number of interfaces, it is

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 Section 3.6

impossible to use all the cross-connection capacity available. The cross-connection capabilities
of a mini node are the same as in SXU-A unit in a basic node. mini nodes can make cross-
connections both at 64 kbit/s and 8 kbit/s level, the bit level cross-connection capacity is 95 TS
and CAS cross-connection capacity is 32 TS. Typically mini nodes are used as an access level
node in a network or as base station transmission equipment in mobile networks.

Tellabs 8170 cluster node

Tellabs 8160
accelerator node A111
Tellabs 8150 basic node
Tellabs 8140 midi node

Tellabs 8110 network terminating unit

Tellabs 8120 mini node
Tellabs 8130 micro node

Fig. 3 Different Nodes

8.5 Micro node :

The total cross-connection capacity of a micro node is 64 Mbit/s. The micro node is fully
non-blocking. They can make cross-connections both at time slot and at bit level. The bit level
cross-connection capacity is 127 TS (8128 kbit/s). micro nodes do not support CAS signaling.
The cross-connection delay is one frame (125 s).

The accuracy of the internal clock is ± 30 ppm and it supports both fallback list and
quality levels. The micro node does not have a build-in test generator or a receiver for circuit
loop testing.

8.6 Accelerator Node:-

It is an access node combining PDH and SDH technologies.

PDH features:-

-Support for many existing interfaces units

-Two X-buses and consequently 2 x 64 Mbps = 128 Mbps capacity

Application e.g. DSLAM

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 Section 3.6

Cross connections are done only at TS level, 64 kbps.

Operated with the network manager

8.7 Switch Node:-

It is an N.E with ADM, LTM and SDXC.

Operated with the network manager

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