Multiplex communications – Communication techniques for information carried in plural... – Combining or distributing information via frequency channels
Reexamination Certificate
2000-08-14
2004-12-07
Nguyen, Brian (Department: 2661)
Multiplex communications
Communication techniques for information carried in plural...
Combining or distributing information via frequency channels
C370S467000, C375S222000, C709S236000
Reexamination Certificate
active
06829252
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to telecommunication systems and more particularly relates to a digital subscriber line access multiplexer (DSLAM) adapted for use with an Ethernet over Very High Speed Digital Subscriber Line (VDSL) transport facility.
BACKGROUND OF THE INVENTION
There is a growing need among both individuals and enterprises for access to a commonly available, cost effective network that provides speedy, reliable services. There is high demand for a high-speed data network, one with enough bandwidth to enable complex two-way communications. Such an application is possible today if, for example, access is available to a university or a corporation with sufficient finances to build this type of network. But for the average home computer user or small business, access to high speed data networks is expensive or simply impossible. Telephone companies are therefore eager to deliver broadband services to meet this current explosion in demand.
One of the problems is that millions of personal computers have found their place in the home market. Today, PCs can be found in approximately 43% of all United States households and a full 50% of United States teenagers own computers. Virtually every PC sold today is equipped with a modem, enabling communication with the outside world via commercial data networks and the Internet. Currently, people use their PCs to send and receive e-mail, to access online services, to participate in electronic commerce and to browse the Internet. The popularity of the Internet is such that there are an estimated 50 million users around the globe. These figures indicate that in the past few years the personal computer has fueled a dramatic increase in data communications and the corresponding demands on the data networks that carry the traffic.
The Internet serves as a good example of the increased demands that have been placed on data networks. At first, Internet access consisted of text only data transfers. Recently, with the popularity of the World Wide Web (WWW) and the construction of numerous sites with high quality content, coupled with the development of Internet browsers such as Mosaic, Netscape Navigator and Microsoft Explorer, the use of graphics, audio, video and text has surged on the Internet. While graphics, audio and video make for a much more interesting way to view information as opposed to plain text, bandwidth consumption is significantly increased. A simple background picture with accompanying text requires approximately ten times the bandwidth needed by text alone. Real-time audit and streaming video typically need even more bandwidth. Because of the increased requirement for bandwidth, activities such as browsing home pages or downloading graphics, audio and video files can take a frustratingly long period of time. Considering that the multimedia rich World Wide Web accounts for more than one quarter of all Internet traffic, it is easy to see why the demand for bandwidth has outpaced the supply. In addition, the creative community is pushing the envelope by offering audio and full motion video on numerous sites to differentiate themselves from the millions of other sites competing for maximum user hits.
As use of the Internet and online services continues to spread, so does the use of more complex applications, such as interactive video games, telecommuting, business to business communications and video conferencing. These complex applications place severe strains on data networks because of the intensive bandwidth required to deliver data-rich transmissions. For example, a telecommuter who requires computer aided design (CAD) software to be transported over the data network requires a high-bandwidth data pipeline because of the significant size of CAD files. Similarly, a business-to-business transaction in which large database files containing thousands of customer records are exchanged also consumes large amounts of bandwidth. The same is true for users seeking entertainment value from sites offering high quality video and audio. The lack of available bandwidth in today's data networks is the primary barrier preventing many applications from entering mainstream use. Just as processing power limited the effectiveness of early PCs, bandwidth constraints currently limit the capabilities of today's modem user
Considering the networking needs of hotel guests, the vast majority of hotel guests are currently forced to use conventional dial up connections at relatively slow data rates. A recent trend in the industry is to try to accommodate guest's networking needs and their desires for fast Internet access by installing in-room data ports and increasing the capacity of hotel PBX systems and trunk lines. Despite the equipment and facility upgrades, however, the typical PBX cannot support laptop speeds of 56 kbps. The best most PBX systems can handle is 14.4 kbps speeds. Which such slow connectivity, guests quickly become frustrated and the hotel PBX is crippled when stretched to capacity during peak usage hours. Having guests log in over dial up lines, burdens the hotel's switchboard which may get tied up in knots for hours due to a large number of guests on-line simultaneously. The problem is so bad that, in response, some hotel chains add on extra telephone charges to guests' bills for local calls longer than a half hour.
The current situation is, therefore, unacceptable in the fast paced environment of today, particularly for the business traveler. The demand for high speed Internet access in hotel guest rooms is growing rapidly, especially when considering most hotel guests are already used to fast Internet access in their homes and offices.
Further, the demand for faster Internet access is growing at hotel meeting and convention facilities. Meeting attendees and tradeshow exhibitors are increasingly requesting fast access service. It is thus expected that in the future, high speed Internet access will become a standard for any hotel catering to the business and convention traveler, in addition to an increasing number of leisure travelers.
Some currently used methods of accessing the Internet are described below, beginning with the common POTS method, Most computer modem users currently access data through the standard telephone network, known as plain old telephone service (POTS). Even when equipped with today's speediest modems, dial up modems on a POTS network can access data only at a rate of 28.8, 33.6 or 56 Kbps. Dial up modem transmission rates have increased significantly over the last few years, but POTS throughput is ultimately limited to 64 Kbps. While this rate may be acceptable for some limited applications like e-mail, it is a serious bottleneck for more complex transactions, such as telecommuting, video conferencing or full-motion video viewing. To illustrate, full motion video compressed, using the Motion Picture Entertainment Group (MPEG)-2 standard requires a data stream or approximately 6 Mbps, or roughly 208 times the throughput of a 28.8 Kbps modem. Thus, using today's dial up modems, it would take more than 17 days to capture two hours of video. As bandwidth demands continue to grow, providers search for better ways to offer high speed data access. Further complicating the problem is the need to deliver all these complex services at an affordable price.
Today's most popular data access method is POTS. But as discussed previously, POTS is limited when it comes to large data transfers. An alternative to POTS currently available is Integrated Services Digital Network (ISDN). In the past few years, ISDN has gained momentum as a high-speed option to POTS. ISDN expands data throughput to 64 or 128 Kbps, both from the network to the user (i.e. enterprise, hotel, home, etc.) and from the user back to the network, and can be technically made available throughout much of the United States and in many other parts of the globe. Similar to POTS, ISDN is a dedicated service, meaning that the user has sole access to the line thus preventing other
Lewin Amit
Poddobny Yuri
3Com Corporation
Nguyen Brian
Zaretsky Howard
LandOfFree
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