Dsl

DSLDSLDigital Subscriber LineDigital Subscriber Line

Presented by :Presented by :

AL-Maqashi Saleem (49)AL-Maqashi Saleem (49)

Patkar college Patkar college

Agenda

Aim of DSL What is DSL? PROs & CONs Block diagram DSL standards Conclusion References

The Need for Speed

Explosive Growth of the Internet

Increase Demand for High-Speed Access By Businesses & Individuals

Increase Demand for New Applications Real-time interactive multimedia Video conferencing Distance learning

What is DSL?

Digital Subscriber Line A technology which uses the existing

transmission medium (telephone wire) to provide high-speed transfer of information across the internet.

DSL simply uses more of the bandwidth. DSL allows simultaneous voice and high-speed data

services such as super fast Internet access over a single pair of copper telephone wires.

Common Types of DSL

How It Works

A. Over the Wire: You are connected to another ADSL modem which also has a POTS splitter, which separates voice calls from data.

B. Telephone Calls: Voice calls are routed to the phone company's public switched telephone network (PSTN) and proceed on their way as usual.

C. Internet Requests: DSL Access Multiplexer links many ADSL lines to a single high-speed asynchronous transfer mode (ATM) line, which in turn connects to the Internet.

D. Back at You: The requested data is retrieved from the Internet and routed back to you.

Plain old telephone service

Advantages of DSL

The following are some advantages of DSL service: Broadband Internet and Phone at the same time: You

can be online on facebook and twitter and at the same time talk to your friend on your landline connection. This was not possible with dial- up connection as going online meant you could not use your landline phone.

Faster Internet: It is was faster than the 52 kbps dial up connection. DSL internet provides speed of above 2mbps 

No wiring: Since DSL broadband connection uses phone line to connect to the net no special wiring is required

Con,,,,

No Dropped Connections: A major problem with dial up connection was that it would disconnect all of a sudden leaving you high and dry. DSL connections do not have these problems and seldom is there a disconnection.

Faster Downloads: Faster DSL network means, that downloads are faster. Now you can download more files in the same time.

Multiple Computers on Single DSL Line: More computers can be connected to internet using the same DSL connection. That means no need to take special connection for an extra computer or laptop.

disadvantages of DSL

The following are some disadvantages of DSL: Your DSL connection works faster if you live

closer to the provider’s central office. The farther your home is from the ISP’s office the more your speed will reduce.

Data being received is faster than data being sent over the Internet.

DSL availability is limited to certain cities, not everyone can get this service

DSL Architecture

Digital Subscriber Line (DSL) is the newest technology being used for Internet access. DSL connects your home or office to the Internet through the same telephone wire . Like ISDN, with DSL, user can make and receive telephone calls while connected simultaneously to the Internet .

To use DSL you will need a DSL modem (also called a router), a Network Interface Card (NIC), and a telephone line. DSL is also relatively new technology that is just being introduced in many places . Hardware developers are working with service providers to make the service cost affordable for consumers. As time goes by, the service should become more widely available at a reasonable price.

DSL BLOCK DIAGRAM

Two standards for DSL

1- Discrete multitone (DMT) : is a form of FDM that divide data into 256 downstream and 32 as upstream channels .

Discrete Multi-Tone (DTM), a multi-carrier modulating technology, is generally used as the modulation standard for ADSL. DTM is very resistant to noise.

2- Carrierless amplitude/phase (CAP) : is a version of QAM by dividing the signals into three part ,, voice , upstream and downstream .

Conclusion

It is highly likely that xDSL will become widely adopted particularly among high-speed Internet "power users" as well business requiring fast access to various networks, provided naturally that the prices come down.

xDSL technology offers a viable interim solution to the bandwidth problem while fiber optic cables are being installed.

References

Data Network Design -Selected pages (3rd Edition) darren L. Spohn

ADSL Forum, "General Introduction to Copper Access Technologies", http://www.adsl.com/adsl/general_tutorial.html

The Need for Speed", http://www.kentrox.com/product/cellworx/nspeed/xDSLprimer.html

Thank you ……………

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