Data Bases • Custom Term Papers • Free Term Papers • Free Research Papers • Free Essays • Free Book Reports • Plagiarism? Links • Top 100 Term Paper Sites • Top 25 Essay Sites • Top 50 Essay Sites • Search 97,000 Papers @ DirectEssays.com • Search 101,000 Papers @ ExampleEssays.com • Search 90,000 Papers @ MegaEssays.com Free Essays • Term Paper Sites • Chuck III's Free Essays • Free College Essays • TermPaperSites.com • Free Essays • My Term Papers • Essay World • Planet Papers	Search Lots of Essays Back to Subjects - Computers DSL VS CABLE DSL VS CABLE The market for interactive home video services via x.DSL and Cable offer consumers a variety of opportunities over a high-speed connection. Each service, with its own advantages, share one important factor that consumers value most; high quality service at relatively low costs. Although, currently both technologies are in competition with each other, eventually one will prevail creating a standard for interactive home video. The first service to be analyzed is x.DSL or Digital Subscriber Line. DSL is a technology for bringing high-bandwidth information to homes and small businesses over ordinary copper telephone lines. xDSL refers to different variations of DSL, such as ADSL, HDSL, and RADSL. Assuming your home is close enough to a telephone company central office that offers DSL service, you would be eligible to receive data at rates up to 6.1 megabits per second, enabling continuous transmission of motion video, audio, and even 3-D effects. It is most likely that individual connections will provide from 1.544 Mbps to 512 Kbps downstream and about 128 Kbps upstream. DSL assumes digital data does not require change into analog form and back. Thus a huge bottleneck is prevented which is normally the issue with analog transmission from local phone companies. Digital data is transmitted to your computer directly as digital data and this allows the phone company to use a much wider bandwidth for transmitting it to you. A DSL line can carry both data and voice signals and the data part of the line is continuously connected. Compaq, Intel, and Microsoft working with telephone companies, have developed a standard and easier-to-install form of ADSL called G.Lite that is expected to accelerate deployment. DSL has pretty much replaced ISDN in many areas. Dataquest, a market research firm, forecasts 5.8 million lines installed by the end of the century. Installation of DSL requires that a signal splitter be installed at the home. This requires the expense of a phone company visit and installation. However, it is possible to manage the splitting remotely from the central office. Next a DSL modem is required for modulation. DSL modems are using Discrete Multitone Technology (DMT), Carrierless Amplitude Modulation (CAP) and Multiple Virtual Line (MVL) for modulating. To interconnect multiple DSL users to a high-speed backbone network, the telephone company uses a Digital Subscriber Line Access Multiplexer (DSLAM). The DSLAM connects to an asynchronous transfer mode (ATM) network that aggregates data transmission at gigabit rates. At the other end of each transmission, a DSLAM demultiplexes the signals and forwards them to the appropriate individual DSL connections. x.DSL presents numerous opportunities to the home consumer. Features such as high speed Internet access, software on demand (SOD), videoconferencing, streaming video and voice signals, are all very attractive to the common dial-up customer. One example where SOD is a key feature, is a CD-ROM Shim developed on the Mpowered platform (by MTT). This is a customer designed software layer that lets end users who do not have CD-ROM equipped computers run CD-ROM dependent applications. The SOD platform will also offer users access to real-time billing information. What’s even more attractive is the fact that DSL presents a nailed circuit in which one is continuously connected. Also unlike cable, DSL works over existing phone lines and because each user has their own dedicated circuit, there is no competing for bandwidth with neighbors in your area. The most widely used form of X.DSL is ADSL (Asymmetric Digital Subscriber Line). ADSL is called "asymmetric" because most of its duplex bandwidth is devoted to the downstream direction, sending data to the user. Only a small portion of bandwidth is available for upstream or user-interaction messages. However, most Internet and especially graphics- or multi-media intensive Web data need lots of downstream bandwidth, but user requests and responses are small and require little upstream bandwidth. Using ADSL, up to 6.1 megabits per second of data can be sent downstream and up to 640 Kbps upstream. The high downstream bandwidth means that your telephone line will be able to bring motion video, audio, and 3-D images to your computer or hooked-in TV set. In addition, a small portion of the downstream bandwidth can be devoted to voice rather data, and you can hold phone conversations without requiring a separate line. The original intent of x.DSL was to compete with CATV companies in delivering video on demand content to their subscribers. Although ADSL can realistically deliver near-broadcast quality at 300Kbps data rates and best viewed at a 1/3 of the screen, it is still not comparable to CATV. Applications such as instructional videos will work well via ADSL because of low motion involved. Marginal full screen video, for video on demand purposes is much more desirable. It is currently in trial via RADSL (rate-adaptive DSL) with Pacific Bell and US west, requiring at least 750 Kbps for an MPEG-4 video stream. The more definite answer to directly compete with CATV is VDSL (Very High data rate DSL). VDSL promises between 51 and 55 Mbps over lines up to 1000 feet in length. Downstream rates range from 13Mbs to 30Mbps. It is based on fiber-to-the-curb architecture (FTTC/N) and is more expensive to deploy. Currently in limited trial deployment by US West and NEXT Level in Phoenix,AZ provides True broadcast quality video. The Phoenix system, featuring NEXT Level supplied servers, switches, and CPE, serves clusters of 16 to 32 users whose homes are fed by fiber from local switches. The system easily supports 265 channels of video per home. Thousands of channels of programming could easily be delivered over a VDSL network, allowing any school, church, community group or commercial programmer to distribute video-based material. A switched network, such as Next Level’s, can receive programs from anywhere and distribute them to selected subscribers for minimal additional cost, estimated to be less than $0.20 per subscriber per month. It is envisioned that VDSL will merge after ADSL is widely deployed and co-exist with it. The alternative service for interactive home video is x.DSL’s direct competitor, CATV. Features that may develop via cable technology include; remote video game playing where people from different countries can play games with 3D video and sound online, household bill paying, video on demand, bandwidth on demand applications, and web shopping. A numerous amount of servers could be available to the market for streaming audio and video, CD-ROMs, or a variety of software that can be rented by time or one-time use for evaluation before purchasing. To obtain a CATV connection requires the use of a cable modem setup in the subscriber’s home. This device enables you to hook up your PC to a local cable TV line and receive data at about 1.5 Mbps. A cable modem can be added to or integrated with a set-top-box that provides your TV set with channels for Internet access. In most cases, cable modems are furnished as part of the cable access service and are not purchased directly and installed by the subscriber. A cable modem has two connections: one to the cable wall outlet and the other to a PC or to a set-top box for a TV set. Typically, the cable modem attaches to a standard 10Base-T Ethernet card in the computer. All of the cable modems attached to a cable TV company coaxial cable line communicate with a Cable Modem Termination System (CMTS) at the local cable TV company office. All cable modems can receive from and send signals only to the CMTS, but not to other cable modems on the line. Some services have the upstream signals returned by telephone rather than cable, in which case the cable modem is known as a one-way cable modem. Two-way service is available where the cable plant has been upgraded to a two-way HFC (Hybrid Fiber Coax, i.e. fiber optics). In these systems, the cable modem can both send and receive data. The actual bandwidth for Internet service over a cable TV line is up to 27 Mbps on the download path to the subscriber with about 2.5 Mbps of bandwidth for interactive responses in the other direction. However, since the local provider may not be connected to the Internet on a line faster than a T-1 at 1.5 Mpbs, a more likely data rate will be close to 1.5 Mpbs. To determine which service is the best one for the home user depends mostly on cost and the future of the service. Since cost for both x.DSL and cable are nearly the same, a decision should be made upon the expansion capabilities of each service. Some cost figures and speed differences are outlined on below. High Speed Access Technology Comparison Access Type Always On Ties-up Phone Line Monthly Service Cost* Requires Installation · * Estimated cost, does not include installation charges or hardware rental charges. Access Type Maximum Data Rate Effective Web Browsing Speed* - ADSL/RADSL 6 Mbps 1.5 Mbps 500 Kbps - G.lite 1.5 Mbps 150 Kbps 500 Kbps - Two-way 10 Mbps 800 Kbps 500 Kbps - One-way 10 Mbps 30 Kbps** 500 Kbps Analog Modem- V.32 Modem 30 Kbps 30 Kbps 30 Kbps * Effective Download Speed reflects the actual online performance as reported by customers. While the various technologies may be capable of much higher data rates, under typical web browsing conditions the internet operates at 500 kbps or less. The bottom line is that many of these high speed technologies can pump data as fast as the internet can handle. The ideal service in my opinion for the present time is CATV. However, considering the future of x.DSL and the proposed upgrade to VDSL, would suggest that x.DSL is the ideal option. If VDSL is ever implemented, it will combine all multimedia services into one including voice and video services. However the most important concept of x.DSL technology is the fact that a dedicated circuit will provide exceptional service to each user. This is bottlenecking is very prone to occur with CATV in the future and most users will not be satisfied when their high speed connection slows to a crawl. Cost is the same as CATV at only $50-60 a month for high-speed connectivity. Therefore the choice for the interactive home video service should be x.DSL. Bibliography: www.networkcomputing.com Word Count: 1734
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