Broad Band technology, Next generation network (NGN),DSLAM

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BroadBand Telecom. Networks Workshop

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Objectives of Workshop

• After this session, you will learn:– How to reuse the existing Access Networks for Broadband

Services ?

– One practical Broad Band Access System DSL

– About Upcoming Broadband Systems e.g NGN.

– Connectivity of IP Network for DSL

and other Broadband Services (Access & Core)

– Configuration of IP Network for DSL

• and other Broadband Services

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About this Session

• Background Of Telecommunication Networks ?• Requirements of new Access Technology ?• Broadband Technologies• Digital Subscriber Lines-DSL • DSL-What ?• DSL-When ?• DSL-Why ?• DSL-Flavors• DSL Architecture

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Background Of TelecommunicationNetwork s?

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• Three Basic layers of Telecommunication Network Model are:

1. Access Layer

2. Switching and Services Layer (Core Layer)

3. Transport Layer

Building Blocks of Telecommunication Network Model

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1. Access LayerRepresents the network that links the customers to the

Switch and Services Layer.

2. Switching and Services Layer (Core)Consists of all the Switching Nodes (Local

Exchange ,Transit Exchange etc.)

3. Transport LayerRepresents the links among the nodes and provides the

medium and systems to carry the information from one node to the other.


Contd……

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Contd…

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What is an Access Network (AN) ?

The access network refers to the part of the network, connecting the subscriber to the telecommunication service providing point / exchange.

It is the last link /last Mile in a network between the customer premises and the first point of connection to the Network infrastructure

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Typical Network Construction

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• Changes in Trends

– Technological Evolution

• Demand for High Speed Access

– Broad Band Services– Increase in Internet Usage– Increase in demand of bandwidth

Requirements of new Access Technology

What is broadband ?

• Broader, wider – more bandwidth• More bandwidth than narrow band dial up (56 kbps)• Greater than 128 kbps• Definitions vary from country to country• Higher bandwidths of 256, 512, 1024 kbps and above• Always on• Uses various mediums:

– Copper– Coaxial– Wireless (Microwave ,Satellite etc.) – Optical Fiber

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Broadband Technologies

Why Broadband ?

• In a Telecommunication Network , last mile or first mile is most important. It creats bottleneck

• Development of bandwidth hungry applications

• Convergence of Voice, data and video at one delivery mechanism

• Need for Speed

Growth ofInternationalCommerce

IncreasingMultimediaContents

Increasing Numberof Business Usersand ConsumarSubscribers

New ServiceOfferings andApplications

HigherBandwidth

Bandwidth Market Direction- Spiraling Need for Bandwidth -

Why Broadband ?

Narrow band Services & Broad band Services

• Narrow band Services– Voice – Limited Data

• Broadband Services– Band width Hungry – Multimedia Services ……..Voice + Video + Data

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Narrow band Services & Broad band Services

SPEED !

Broad band Access

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Broad band Access

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Broadband access technologies

• Optical Access Network – FTTH: Fiber To The Home– FTTC: Fiber To The Curb– Passive Optical Networks– HFC (Hybrid Fiber Coaxial)

• xDSL– HDSL (High rate digital subscriber line)– SDSL (Symmetric digital subscriber line)– ADSL (Asymmetric digital subscriber line)– VDSL (Very high bit rate DSL)– IDSL (ISDN DSL)– UDSL (Ultrahigh bit rate DSL)

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• Wireless broadband access– Wireless LAN

– WLL (Wireless Local Loop– Microwave Radio Access (WiMax)– GPRS (General Packet Radio Service)– EDGE ( Enhanced Data GSM or Global Evolution )– CDMA– EVDO

• And many many more........

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Broadband access technologies

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Requirement of new Access Technology

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• Limitations of Conventional Telecomm. Network (PSTN,ISDN) in terms of Broadband services

– Bandwidth Limitation• Analog Modem Connections are limited to 56K.• Basic Rate ISDN limited to 144 Kbps

– Switch Congestion• Voice calls are usually short (say 5 min)• Data calls are usually long (may be 120 mins.)• Flat Charge /Low Charging by ISPs intends users for long

internet usage.

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• Applicable to Existing Network– xDSL– Digital Cross Connect (DXX)– ISDN

• Requiring new Installations– Optical Fiber– Wireless Local Loop– CATV


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xDIGITAL SUBSCRIBER LINE-xDSL ?

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x Digital Subscriber Lines (x DSL)

• Digital Subscriber Line is an Access technology that enables broadband data over twisted copper pairs, opening the most crucial bottleneck in the today’s data stream.

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The three Ws–What ?–Why ?–When ?


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• DSL uses existing telephone lines– Millions of telephone lines around the world.– DSL can provide data and voice over the same phone

line– Users don’t need a second line.– DSL provides service providers with the capability to

leverage the existing infrastructure

• DSL makes economic sense– Reuse of existing telephone Outside Plants and

reduces the deployment costs and risks– Deployed incrementally without large capital

investment.

x Digital Subscriber Lines (x DSL) What ?

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• DSL has many flavors – xDSL is a generic abbreviation for the many flavours

of DSL or DSL Technology.

• DSL enables more bandwidth – DSL refers to the technology used between a

customer’s premises and the telephone company, enabling more bandwidth over the already installed copper cabling than user have traditionally had.

– One may be able to receive data at rates up to 6.1 Mbps (millions of bits) per second (of a theoretical 8.448 megabits per second),


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• Provides a variety of services– Internet Access– Telecommuting (The practice of using

telecommunication technologies to work a site away from office )

– Distant learning – On-line gaming– Remote LAN Access– Videoconferencing etc– Continuous transmission of motion video, audio


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• DSL enables new applications – Services requiring real-time, interactive

multimedia and broadcast-quality video. – Such applications include

• Video conferencing• Video-on-demand • IP TV• Many Many More………


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• Transmission speeds are not affected by other users going on-line – DSL is one customers dedicated line,– Generally transmission speeds are not affected

• DSL is "always on" – DSL is always connected - just like a standard

telephone. There is no time wasted in dialing up the service.


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InternetCustomer Premises

6Mbps

DSL

Public Telephone

Network

Telephone Line

DSL Access Multiplexer

Central Office


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• DSL makes use of Huge Investment which has already been done on Copper

• Eliminates the need for upgrades– Unlike competing technologies, DSL eliminates the

need for extensive and expensive infrastructure upgrades

• DSL bridges gap between latest technologies and copper– DSL is the best Choice to bridge the gap between

the latest bandwidth hungry applications and the already cheaply available copper cable ,

x Digital Subscriber Lines (x DSL) Why ?

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• Saving of time is essential .

High Data rates are required.

• Revenue Saving is desired .

Unmet broadband demand is to be met.

Growing Traffic needs are to be satisfied.

Alternate to insufficient optical fiber deployment is required.

x Digital Subscriber Lines (x DSL) When ?

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How does DSL technology achieve information rates in the millions of bits per second over those same copper loops?

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The answer is simple As most speech energy lay in the frequency range below 3500 Hz. Thus, for faithful reproduction of speech, only a narrow range of frequencies (0-3500 Hz), needs to be transmitted. The telephone networks are designed to pass frequencies in the range 300 – 3400 Hz.DSL uses a much broader range of frequencies than the voice channel . Thus ,eliminating the 3,400-Hz boundary and using all bandwidth of underutilized copper .

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• xDSL modems take advantage of the spectrum above the telephone audio channel.

– DSL increases data rates by greatly increasing the frequency range of the communication signal (from about 10KHz to over 1.0MHz).

– To do this they require the installation of special equipment at the central office and customer premise


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Frequency Range of Copper Line

4 kHz to 1.1 MHz - ADSL Data300 Hz to 3.3 kHz - Analog Voice

Frequency Range

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xDSL-Flavors

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Asymmetric DSL

Symmetric DSL

xDSL-Flavors

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Asymmetric DSL

• Why it is called Asymmetric DSL ?– faster downstream rate vs. upstream rate.

• Applications – Web-browsing, IP TV , Video on demand (VoD)

Asymmetric DSL and Derived Types 1 ADSL2 Universal ADSL (UDSL), G.Lite or DSL Lite3 Rate-Adaptive DSL (RADSL)4 Very High Bit-rate DSL (VDSL)

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• Why it is called Symmetric DSL?– Downstream & upstream rates are equal

• Applications – Office type applications like Video conferencing

• Types – High bit-rate DSL (HDSL)– Single-pair HDSL (SHDSL)– ISDN DSL (ISDL)

Symmetric DSL

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Few key differences1 Speed

How much data can be sent or received in a certain amount of time ?(bit rate)

2 Line CodingHow the information is encoded and sent on the line ?

3 Number of Lines What are the requirements in terms of twisted pairs ?

4 ReachHow many feet/meters the signal can reliably travel ?

Differences in different flavors /variants of DSL

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Asymmetric DSL and Derived Types

Asymmetric DSL and Derived Types

• ADSL

• Universal ADSL (UDSL), G.Lite or DSL Lite

• Rate-Adaptive DSL (RADSL)

• Very High Bit-rate DSL (VDSL)

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• Why it is called ADSL ?– ADSL is called "asymmetric" because most of its two-way

bandwidth is devoted to the downstream direction i.e sending data to the user.

• Data Rate and Reach– Only a small portion of bandwidth is available for upstream or

user-interaction messages. Using ADSL, up to 6.1 Mbps of data can be sent downstream and up to 640 Kbps upstream

– The data rate of ADSL is highly dependent upon the distance from Central Office (CO) to the Consumer Premises

– ADSL is designed to co exist with a regular phone line (phone operates at frequencies up to 4 KHz). ADSL will extend out to 18,000 ft, but its ideal rates only operate out to 9,000 ft.

– Speeds and distances based on good pair

ADSL

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• Advantages– Well suited to residential application.– Peacefully co-exists with current phone service.

• It has large downstream data capacity

– ADSL (like most flavors of xDSL) is always connected

• Disadvantages– For Large business upstream data rates are often

just as important as downstream ,which would make ADSL a poor choice

– Data rates also suffer dramatically as line length increases.

ADSL

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ADSL

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• To create multiple channels ,ADSL Modem divide the available bandwidth of a telephone line by using Frequency Division Multiplexing (FDM).

• By FDM , ADSL splits off a 4 kHz region for basic telephone service at the lower end of the band. One band is used for upstream and one band for downstream is assigned.

ADSL (Operation)

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ADSL Spectrum - FDM

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• DSL Lite, Splitter less ADSL or UADSL (Universal ADSL)

• A derivative of ADSL technology• ITU-T Standard• UADSL is Output of Universal ADSL Working Group (UAWG)

• Slower version • provides a data rate of 1.544 Mbps downstream and from 128

Kbps to 384 Kbps upstream.

• Simpler Hardware design• Because of the lower bit rate, hardware design for G.Lite is

easier

Type of Asymmetric DSL- G.Lite

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• No Splitter Required• Where wiring in the home is old or done poorly,the

voice and data signals can interfere with each other .In those cases ,small Micro Filters are placed on each phone line in the house.

• Higher noise levels can be tolerated, eliminating the need for a POTS splitter.

• Cost effective solution as no splitter required

Types of Asymmetric DSL- G.Lite

55The (3) Divided Segments of G.Lite

• The 0 to 4 kilohertz (KHz) range is used for POTS

• The 20 KHz to 130 KHz range is used to transmit data upstream

• The 140 KHz to 550 KHz range is used to transmit data downstream

Types of Asymmetric DSL- G.Lite

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G.Lite DMT Spectrum

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• RADSL (Rate Adaptive DSL )

• By dynamically decreasing or increasing the bit-rate ,rate adaptive technology uses the optimal speed for the Line.

• Modem periodically assesses line quality and adjust transmission rate

• Generally used to extend reach of systems to areas that are far from the central office.

Types of Asymmetric DSL- RADSL

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• Operates over single twisted-pair copper loop

• Downstream: 1 to 12 Mbps

• Upstream: 0.128 to 1 Mbps.

• In summary RADSL gives flexibility to adapt to the changing conditions and adjust the speeds in each direction to potentially maximize the throughput on each line.

Types of Asymmetric DSL- RADSL

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• VDSL (Very high bit rate DSL)

• Data rates: Up to 52 Mbps (13, 26, or up to 52 ) in one direction and 2 Mbps in the other

• Meets businesses and residences with broadband access requirements over a Fiber-To-The-Curb (FTTC) network.

• Ultra High Speed data access such as Streaming video possible.

Types of Asymmetric DSL- VDSL

61VDSL Network

Type of Asymmetric DSL- VDSL

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Symmetric DSL and Derived Types

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Symmetric DSL

• Why it is called Symmetric DSL?– Downstream & upstream rates are equal

• Applications – office type applications like Video conferencing

• Types – High bit-rate DSL (HDSL)– Single-pair HDSL (SHDSL)– ISDN DSL (ISDL)

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• HDSL (High bit rate Digital Subscriber Line)

– 1.544/2.048 Mbits bi-directional service

• Matured and cheaper type of DSL . • Developed in late 1980’s as an alternative to T1/E1 standards .

• Initially T1/E1 lines were developed and deployed for high speed data transmission.

– They are dedicated lines where there is always a connection between the end user and the service provider.

– A leased T1 /E1 line has customarily been quite expensive.

Type of Symmetric xDSL-HDSL

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Types of Symmetric xDSL-HDSL

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• HDSL was designed to automatically compensate for line conditions.

• HDSL uses Duplex transmission sending data bi-directionally against T1/E1 which uses Simplex Transmission

• HDSL transceivers can transmit a 2.048 Mbps data signal over two, 0.5mm, twisted wire pair loops at a distance of up to 4.2 km without the need for repeaters


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• HDSL is designed to run at the same bit rate as a T1/E1 line (1.544/2.048 Mbps) and it uses the same number of lines, but it can achieve this same bit rate on less expensive lines over a greater distance.

• To do this, it sends a half rate signal (784/1040 kbps) on each line.


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• Advantages– Matured and proven technology. – Very easy and economical to install.– Having decent transfer rate in both directions at 1.544/2.048

Mbps (784/1040 kbps x 2).

• Dis-advantages– Requires two twisted pairs of wires to operate

– High deployment cost for service providers.

– Slightly slower in speed than other forms of DSL,

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Types of Symmetric DSL- SHDSL

• SHDSL (Single-pair HDSL)

• Single twisted pair of wires is used.

• This helps to drive the cost of a system down.

• Having transfer rate in both directions at 1.544/2.048 Mbps .

• SHDSL supports repeaters ,which further increases the reach capability

• It can be used to provide variety of rates between 192 Kbps and 2.312Mbps and can extend 5.5 km @ 256 Kbps.

• Ideally suited to SOHO market

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Types of Symmetric DSL- SHDSL

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• IDSL (ISDN Digital Subscriber Line).

• IDSL provides DSL technology over existing ISDN lines.• • Even though the transfer rates for IDSL are about the

same as ISDN (144kbps v. 128kbps), and IDSL circuits can only carry data (not voice), the major benefits of switching to IDSL from ISDN are

– Always-on connections, as opposed to dial-up, thus eliminating call setup delays;

– Transmission of data over the data network, rather than the PSTN.

Types of Symmetric DSL- IDSL

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DSL Reaches and Rates

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Comparing Access Technologies

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DSL Architecture

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DSL Central Office Components

• DSLAM (Digital Subscriber Line Access Multiplexer)

– Aggregates traffic from multiple DSL Modems and combine it into higher speeds before sending it to the Internet or data network.

– It is a mechanism at a phone Company’s central location that links many DSL customers (Connections) to a single high speed Data Line

– DSLAMs are generally flexible and able to support multiple types of DSL in a central office

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– DSL customer Terminates individual subscriber line and integrates it into the telephone and data networks.

– Multiple DSLAMs are further connected to B-RAS (Broad band Remote Access server) and hence to Internet Cloud.

– Splitters and filters are also located at the telephone company equipment.

– Modern DSLAMs support • Multiple DSL transmission types• ADSL, SDSL, etc• Different protocol • Different modulation techniques


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DSLAM

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• Splitter / Filters– Separates the low frequency voice signals from the

high frequency data signals.– If we will not install the DSL splitter on our telephone

line, the phone line signals can interfere with DSL modem. And we can face noise, low speed data or service break down.

DSL Customer Premises Equipment (CPE)

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DSL Customer Premises Equipment (CPE)

– DSL Modem – Couples DSL to PC or Ethernet Equipment

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PSTN

IP /ATM

Internet

Subscriber Premises

DSLAM

Less than 18,000 ft. --

Local Loop

Splitter

PC with DSL Modem

Central OfficeLow Frequencies

High Frequencies

Network Topology DSL Connection With Splitter

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Network Diagram of DSL

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DSL Coding Techniques

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Coding Techniques for xDSL

• Many approaches have developed as a means of encoding data on to xDSL Circuits

• The Commonly used modulations are – Discrete MultiTone Modulation (DMT)

– Carrierless Amplitude Phase Modulation (CAP)

– Quadrature with Phase Modulation (QAM)

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Line Coding Techniques for ADSL

• Discrete MultiTone Modulation (DMT)– Used in Industries – DMT uses multiple narrowband Carriers ,– DMT systems divide the frequency band into 256 sub

carriers with the standard 4.3125 kHz bandwidth.– 32 of these channels are reserved for upstream data.– All Carriers transmitting simultaneously in a parallel

transmission mode– Each of these carriers carries a portion of the

information being transmitted

88DMT Spectrum

Line Coding Techniques for ADSL

• These carriers can be independently modulated

Current Version of DSLVDSL: Broadband To The Home

Central Office

VDSL

VDSL

FTTCVDSL

VDSL...

Copper

Cop

per

Copper

FTTB

VDSL

VDSLStreet Cabinet

Reach over copper: 300m - 2KmData rates: Up to 52 MbpsSymmetric and Asymmetric operation

• PTCL Announcing Bandwidth (DSL) Data Rate Up to 50 Mbps Using VDSL2 Bonding Technology

• PTCL has become the 1st operator in the world to use VDSL2 Bonding technology to provide to its bandwidth hungry DSL customers with Bandwidth up to 50 Mbps on its existing Copper network.

• VDSL2 Bonding takes two copper based lines per subscriber and aggregates them to almost double the bandwidth speed available to the existing customers and also expands high speed broadband access to areas that are underserved today. Using VDSL2 Bonding technology, service providers can extend the life of their existing copper infrastructure supporting the delivery of bandwidth intensive services such as Triple play service, data and IPTV.

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PTCL Announcing Bandwidth (DSL) Data Rate Up to 50 Mbps

91THANKS

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Picture Abhi baqi ha mery Dost…….

− NGN is based on standard protocols and packet switching network

− In broad sense

− NGN refers to integrated network that adopts new technologies

extensively, focuses on IP, and provides voice, data, and

multimedia service at the same time.

− In narrow sense

− NGN refers to the Open , Integrated and Distributed network

that employs soft switch at the control layer

What is Next Generation Networks (NGN ) ?

Voice+ Data

+Video

Video

What is Next Generation Networks (NGN ) ?

Conventional Network

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And…− I want to protect existing SDH transmission investment − I want to keep current access layer architecture

− Switches are aged .Legacy Switch is designed for Speech . Data Traffic is increasing day by day. Networks are going to be complex and need to be consolidated

What shall I do?

Limitations of Conventional Network

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• NGN will fully replace the TDM network owing :– technical advances– cost savings – long term revenue generation

• The market and technology is mature for the large scale deployment of NGN

• Many operators are taking positive actions

NGN is Ready Now

NGN is Ready Now

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Competitive NGN Competitive NGN equipment priceequipment price

Competitive NGN Competitive NGN equipment priceequipment price

Standardization of Standardization of NGN protocolsNGN protocols

Standardization of Standardization of NGN protocolsNGN protocols

Maturity and Openness Maturity and Openness of NGN servicesof NGN services

Maturity and Openness Maturity and Openness of NGN servicesof NGN services

Settlement of QoS/Security problems

Settlement of QoS/Security problems

More and more commercial More and more commercial NGN applications worldwideNGN applications worldwideMore and more commercial More and more commercial NGN applications worldwideNGN applications worldwide

More successful More successful interoperability testinteroperability test

More successful More successful interoperability testinteroperability test

NGN is Ready Now

SignalingModule

Trunk Module UserAccess Module

Expanded Services SoftSwitch

Trunk MediaGateways

SignalingGateway

Comparison of Circuit switching in TDM Switch Model and Packet switching in NGN Model

Access Media Gateway

CPU

Switching Array

Intelligent Network (SCP)

IP Core

IP NetworkMultimedia PC

Multimedia PC

Initially, PC to PC voice calls over the Internet

PSTN

TMGGateway for Media &

Signaling

PSTN

TMG

Gateway for Media & Signaling

Public Switched Telephone Network

Gateways allow PCs to also reach phones

…or phones to reach phones

Hybrid Networks

• Four Layers Model of NGN

1.Edge Access Layer

2.Core Switching Layer

3.Network Control Layer

4.Service Management Layer

Next Generation Networks NGN(Architecture of NGN)

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Four Layers Model of NGN

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Soft Switch Interfaces and Protocols

MRS

IADAMG

TMG

SG

Heart Beat

SIGTRAN

H.248

MGCP

MGCP/SIP/H.323

MG

CP

/ H

.24

8

EPhone

SIP

SIP

H.323

MML/SNMP/CORBA

Network management

FTP

BC (Billing center )

Soft switch SoftSwitch

H.323

SCP

INA

P

PA

RLA

Y

APP Server

M

GC

P

Service Layer

Control layer

Access Layer

Other Network

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Any comments or questions?

Thank you !