Using Telephone and Using Telephone and Cable Networks for Data Cable Networks for Data

TransmissionTransmission

Semester: 131Semester: 131

Course: CSET 221 Computer NetworkingCourse: CSET 221 Computer Networking

Instructor: Farhan KhanInstructor: Farhan Khan

Computer Science & Engineering Technology UnitComputer Science & Engineering Technology Unit

Hafr Al-Batin Community CollegeHafr Al-Batin Community College

22

OutlineOutline Telephone linesTelephone lines Dial-up modemsDial-up modems Digital Subscriber Line (DSL)Digital Subscriber Line (DSL) Cable TV networksCable TV networks

33

Telephone LinesTelephone Lines Traditional telephone lines can carry Traditional telephone lines can carry

frequencies between 300 and 3300 frequencies between 300 and 3300 HzHz Giving them a bandwidth of 3000 HzGiving them a bandwidth of 3000 Hz

All this range is used for transmitting All this range is used for transmitting voicevoice A great deal of interference and A great deal of interference and

distortion can be accepted without loss distortion can be accepted without loss of intelligibilityof intelligibility

44

Telephone Line Telephone Line BandwidthBandwidth

55

Dial-Up ModemsDial-Up Modems

Modemstands for modulator/demodulator.

66

56K Modems56K Modems

9.9.77

After traditional modems reached their peak After traditional modems reached their peak data rate, telephone companies developed data rate, telephone companies developed another technology, DSL, to provide higher-another technology, DSL, to provide higher-speed access to the Internet. speed access to the Internet. Digital Digital subscriber linesubscriber line ( (DSLDSL) technology is one of ) technology is one of the most promising for supporting high-the most promising for supporting high-speed digital communication over the speed digital communication over the existing local loops. existing local loops. ADSLADSL LiteHDSLSDSLVDSL

Topics discussed in this section:Topics discussed in this section:

Digital Subscriber Line Digital Subscriber Line (DSL)(DSL)

88

Digital Subscriber Line Digital Subscriber Line (DSL)(DSL) Provides higher-speed access to the Provides higher-speed access to the

InternetInternet Supports high-speed digital Supports high-speed digital

communication over the existing local communication over the existing local loopsloops

The existing local loops can handle The existing local loops can handle bandwidths up to 1.1 MHzbandwidths up to 1.1 MHz

99

ADSLADSL ADSLADSL – Asymmetric Digital – Asymmetric Digital

Subscriber LineSubscriber Line Downstream bit rate > upstream bit rateDownstream bit rate > upstream bit rate Designed for residential usersDesigned for residential users Unsuitable for businessesUnsuitable for businesses

ADSL operates on existing local loopsADSL operates on existing local loops Local loops can handle up to 1.1 MHz of Local loops can handle up to 1.1 MHz of

bandwidthbandwidth The distance limit is ~18,000 feetThe distance limit is ~18,000 feet The system uses a data rate based on The system uses a data rate based on

the condition of the local loop linethe condition of the local loop line

ADSL is an asymmetric communication technology designed for residential users; it is not suitable

for businesses.

The existing local loops can handle bandwidths up to 1.1 MHz

ADSL is an adaptive technology. The system uses a data ratebased on the condition of

the local loop line.

1313

Bandwidth Division in Bandwidth Division in ADSLADSL

1414

Discrete Multi-Tone Discrete Multi-Tone ModulationModulation Or Or DMTDMT

1515

Allocation and modulation of each channel are determined adaptively

4Khz

Bandwidth DivisionBandwidth Division

1616

VoiceVoice – Channel 0 – Channel 0 IdleIdle – Channels 1-5 – Channels 1-5 UpstreamUpstream – Channels 6-30 – Channels 6-30

24 data channels, 1 control channel24 data channels, 1 control channel 1.44 Mbps (max) upstream bit rate1.44 Mbps (max) upstream bit rate Actual bit rate: 64 Kbps to 1 MbpsActual bit rate: 64 Kbps to 1 Mbps

DownstreamDownstream – Channels 31-255 – Channels 31-255 224 data channels, 1 control channel224 data channels, 1 control channel 13.4 Mbps (max) downstream bit rate13.4 Mbps (max) downstream bit rate Actual bit rate: 500 Kbps to 8 MbpsActual bit rate: 500 Kbps to 8 Mbps

Bandwidth DivisionBandwidth Division

1717

ADSL Customer ADSL Customer ResidenceResidence

1818

DSL Access MultiplexerDSL Access Multiplexer Or Or DSLAMDSLAM

1919

Other DSL TechnologiesOther DSL Technologies HDSL – High-bit-rate DSLHDSL – High-bit-rate DSL SDSL – Symmetric DSLSDSL – Symmetric DSL VDSL – Very-high-bit-rate DSLVDSL – Very-high-bit-rate DSL ADSL2ADSL2 ADSL2+ADSL2+

See alsoSee also http://en.wikipedia.org/wiki/http://en.wikipedia.org/wiki/

Digital_subscriber_lineDigital_subscriber_line

Source: AWARE. ADSL2 and ADSL2+ The new ADSL standard.

9.9.2020

Table 9.1 Summary of DSL technologies

9.9.2121

The The cable TV networkcable TV network started as a video started as a video service provider, but it has moved to the service provider, but it has moved to the business of Internet access. In this section, business of Internet access. In this section, we discuss cable TV networks; in next we discuss cable TV networks; in next Section we discuss how this network can be Section we discuss how this network can be used to provide high-speed access to the used to provide high-speed access to the Internet.Internet.

Traditional Cable NetworksHybrid Fiber-Coaxial (HFC) Network

Topics discussed in this section:Topics discussed in this section:

Cable TV NetworksCable TV Networks

2222

Cable TV NetworksCable TV Networks Started as a video service provider, Started as a video service provider,

then moved to the business of then moved to the business of Internet accessInternet access

Communication is simplex

Communication in the traditional cable TV network is unidirectional.

2424

Hybrid Fiber-Coaxial Hybrid Fiber-Coaxial NetworkNetwork Or Or HFCHFC Bidirectional communication is Bidirectional communication is

achievedachieved

Communication in an HFC cable TV network can be bidirectional.

Cable companies are now competing Cable companies are now competing with telephone companies for the with telephone companies for the residential customer who wants high-residential customer who wants high-speed data transfer. In this section, we speed data transfer. In this section, we briefly discuss this technology.briefly discuss this technology.

Bandwidth CM and CMTS

Topics discussed in this section:Topics discussed in this section:

Cable TV for Data Cable TV for Data TransferTransfer

2727

Division of Coaxial Cable Band by Division of Coaxial Cable Band by CATVCATV

Downstream Video Band can accommodate Downstream Video Band can accommodate more than 80 channels. more than 80 channels. Each TV channel occupies 6 MHzEach TV channel occupies 6 MHzTheoretical downstream data rate is 30 MbpsTheoretical downstream data rate is 30 MbpsTheoretical upstream data rate is 12 MbpsTheoretical upstream data rate is 12 Mbps

9.9.2828

Downstream data are modulated using the QAM modulation technique.

The theoretical downstream data rateis 30 Mbps.

9.9.3030

Upstream data are modulated using the QPSK modulation technique.

Note

The theoretical upstream data rate is 12 Mbps.

3232

Cable Modem (CM)Cable Modem (CM)

3333

Cable Modem Transmission Cable Modem Transmission SystemSystem Or Or CMTSCMTS

3434

SummarySummary Telephone linesTelephone lines Dial-up modemsDial-up modems Digital Subscriber Line (DSL)Digital Subscriber Line (DSL) Cable TV networksCable TV networks