Presentation on theme: "Using Telephone and Cable Networks for Data Transmission"— Presentation transcript:
1Using Telephone and Cable Networks for Data Transmission Semester: 131Course: CSET 221 Computer NetworkingInstructor: Farhan KhanComputer Science & Engineering Technology UnitHafr Al-Batin Community College
2Outline Telephone lines Dial-up modems Digital Subscriber Line (DSL) Cable TV networks
3Telephone LinesTraditional telephone lines can carry frequencies between 300 and 3300 HzGiving them a bandwidth of 3000 HzAll this range is used for transmitting voiceA great deal of interference and distortion can be accepted without loss of intelligibility
7Topics discussed in this section: Digital Subscriber Line (DSL)After traditional modems reached their peak data rate, telephone companies developed another technology, DSL, to provide higher-speed access to the Internet. Digital subscriber line (DSL) technology is one of the most promising for supporting high-speed digital communication over the existing local loops.Topics discussed in this section:ADSLADSL LiteHDSLSDSL VDSL
8Digital Subscriber Line (DSL) Provides higher-speed access to the InternetSupports high-speed digital communication over the existing local loopsThe existing local loops can handle bandwidths up to 1.1 MHz
9ADSL ADSL – Asymmetric Digital Subscriber Line Downstream bit rate > upstream bit rateDesigned for residential usersUnsuitable for businessesADSL operates on existing local loopsLocal loops can handle up to 1.1 MHz of bandwidthThe distance limit is ~18,000 feetThe system uses a data rate based on the condition of the local loop line
10ADSL is an asymmetric communication technology designed for residential users; it is not suitable for businesses.
11The existing local loops can handle bandwidths up to 1.1 MHz
12ADSL is an adaptive technology. The system uses a data rate based on the condition of the local loop line.
15Bandwidth Division 4Khz Allocation and modulation of each channel are determined adaptively
16Bandwidth Division Voice – Channel 0 Idle – Channels 1-5 Upstream – Channels 6-3024 data channels, 1 control channel1.44 Mbps (max) upstream bit rateActual bit rate: 64 Kbps to 1 MbpsDownstream – Channels224 data channels, 1 control channel13.4 Mbps (max) downstream bit rateActual bit rate: 500 Kbps to 8 Mbps
21Topics discussed in this section: Cable TV NetworksThe cable TV network started as a video service provider, but it has moved to the business of Internet access. In this section, we discuss cable TV networks; in next Section we discuss how this network can be used to provide high-speed access to the Internet.Topics discussed in this section:Traditional Cable NetworksHybrid Fiber-Coaxial (HFC) Network
22Cable TV NetworksStarted as a video service provider, then moved to the business of Internet accessCommunication is simplex
23Communication in the traditional cable TV network is unidirectional.
24Hybrid Fiber-Coaxial Network Or HFCBidirectional communication is achieved
25Communication in an HFC cable TV network can be bidirectional.
26Topics discussed in this section: Cable TV for Data TransferCable companies are now competing with telephone companies for the residential customer who wants high-speed data transfer. In this section, we briefly discuss this technology.Topics discussed in this section:Bandwidth CM and CMTS
27Division of Coaxial Cable Band by CATV Downstream Video Band can accommodate more than 80 channels.Each TV channel occupies 6 MHzTheoretical downstream data rate is 30 MbpsTheoretical upstream data rate is 12 Mbps
28Downstream data are modulated using the QAM modulation technique.
29The theoretical downstream data rate is 30 Mbps.
30Upstream data are modulated using the QPSK modulation technique. NoteUpstream data are modulated using the QPSK modulation technique.