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High Speed Internet Solutions at Home With Cable Modems
James (Russ) Rogers
CSMN 636 - Section 9040
Dr. Jim Kasprzak
University of Maryland, University College
April 30, 1999
Abstract
This paper will attempt to give a clear overview of the current growth of cable modem Internet systems and what difficulties the cable companies face. An effort will be made to ensure that the reader understands how cable modem systems operate, what they have to offer, and what their pros and cons are. With so many high-speed Internet connection options available, we'll do a comparison on the top three for home users. This paper will also strive to present the reader with a glimpse of what the future holds for high- speed cable modem services.
Cable Modems: Considering the Alternatives.
Internet usage has skyrocketed throughout the world in the last few years and the home market has been one of the biggest reasons for this. People in countries around the world have found that they can now visit anywhere without leaving their homes. Recent findings from the Emerging Technology Research Group show that the average number of Internet users that are online each evening is more than almost any other form of mass communication. For instance, the USA Today newspaper has a circulation of 1.6 million; Sport Illustrated has a circulation of about 3.2 millions; and the average number of viewers of any one network TV station, at any one time during an evening, is only 15.7 million. In stark contrast to this, the average number of people on the Internet is 40-45 million people (ERTG 1998). The trend is increasing growth in this new media monster and as more people access the Internet, the applications they use demand faster and more reliable connections. Email used to be the "killer app" on the Internet, but it's quickly being replaced by applications like Video Conferencing, Ecommerce, and Streaming audio and video broadcasting. These new applications are drawing the crowds, but they are also putting a strain on existing dial-up connections. New technologies now promise to bring fast and reliable connections to the home user. Cable modems are one of these new technologies. But cable modems have competition from other technologies such as ADSL and ISDN. All of these offer the home user faster speeds, but which options make more sense? The best choice is one that offers a great deal of speed with the least amount of hassle during installation and during use. It must also be relatively affordable or it won't have a widespread impact on society. We almost need some semblance of reliability during use and knowledgeable technical support when something happens to our connection. There are lots of options available for the home Internet user but none of them has taken the market by storm. The Integrated Services Digital Network, or ISDN, has been around for a few years, but has yet to achieve widespread acceptance. The Asymmetric Digital Subscriber Line, or ASDL, is a recent newcomer to the home market and it's future is still uncertain. Cable Modems are also relatively new to the market. ISDN was first standardized about 10 years ago and has been a steadily growing market. The basic premise behind ISDN is that the original copper phone lines that now weave a gigantic web around, connecting telephones, were never meant to handle the amount of traffic that we need in the digital age. Copper lines are typically great for handling low grade voice traffic, but when digital traffic is sent across a small copper telephone line, we see increased error rates. ISDN is an effort by telephone companies to reverse this effect. ISDN networks use the existing two copper lines that come into your house now to send digital traffic (Eicon Technology 1997) . You can get a single channel ISDN connection or a dual channel connection into your home. The single channel offers network speeds of 64Kbps and the dual channel offer speeds of 128Kbps. ISDN requires a digital modem but these aren't that difficult to find. The big plus of this system is that it uses the existing wiring in your home and because it's digital, it is more reliable.
The downsides of ISDN are sometime a little more than simply annoying side effects. ISDN is digital and it's running through your existing phone lines. This, in turn, means that you need a digital telephone to access phone service through those same phone lines. Digital phones are quite a bit more expensive than normal analog telephones. ISDN is also more costly in most areas compared to other high speed Internet solutions for the home. With a higher per month premium and a per minute access charge, the costs involved with ISDN may be keeping many people away from this solution. The Asymmetric Digital Subscriber Line (ADSL) is a new player in the high speed Internet market for home users. It has the same goal of providing high speed, network connections using your current copper telephone wires. The speed provided by ADSL is dramatically faster than ISDN in most cases. The downstream speed from the provider to the home can reach 8Mbps and the upstream from the user to the provider can reach 1Mbps. This is a dramatic improvement over what ISDN currently offers. ADSL speeds are also affected by line length and current line conditions. The benefits of ADSL ( ADSL Forum 1998) include it's speed, of course, but there are others. Having ADSL allows you to surf the Internet and still talk on the telephone or send a fax across the same line. It is also a constant connection to the network, much like ISDN. ADSL is aimed at users of interactive video and other applications that require high speed connections. Unlike ISDN, the phone companies don't require expensive equipment upgrades to existing switches because ADSL is just an overlying network. And since phone lines are in so many homes already, it's possibly quite accessible. The downsides of ADSL are simple. Because it's so young, it is not available is many areas, even though there are phone lines in most homes. The prices, at this point, are still higher than some other choices, such as cable modems, but the company intend on being competitive. ADSL also requires special equipment to hook the computer to the network, but that's not a show-stopper. At this point the cost and the digital phone will keep most folks out of the water. There is good future for ADSL if the companies involved can keep up with the eventual move from copper wires in the home to a faster media. The last option I'll discuss is Cable Modems. Cable modems have had a lot of high visibility in recent years because a lot of people already have cable television. Cable modems work on the same cable as your cable television comes across. Although they share the same medium, the television signal and the Internet signal operate at different frequencies, and thus don't interfere with each other. Cable modems are more affordable than most other forms of high speed access for home users and the connection is a constant connection. The transmission speed downstream is roughly 30Mbps but is shared by all the users on that network segment. The upstream speed is typically limited to 500Kps by the cable modem itself and a filter that is installed on the line. This keeps the network safe from floods coming from user's computers. Cable Modems have their downsides, as well. Although many homes are already wired for cable television, there are many more that are not. This cuts down on their availability, but the growth of cable TV is also helping the cable modem market to grow quickly. The coaxial cable, used by most cable companies, allows up to 30Mbps transfers downstream. This throughput is shared by all the users on the network segment. This normally won't affect a single user's throughput, but it's a possibility if all the cable customers begin to use cable modems, as well. Using a cable modem also means that you will need a cable modem for the network and a network card for your computer. Installing a network card in today's "plug and play" computer world is usually quite simple. The cable modem is also simple to install since it attaches to the network card. One of the big pluses of getting a cable modem is that the cable company is often the one who pays for the cable modem, you just "rent" the modem by paying your monthly bill. This is a good thing because the standards for cable modems are still being solidified by IEEE. Until the powers that be decide upon a suitable standard, cable modems are subject to change. If you don't own the modem, then the company has to upgrade you when the network upgrades to meet the final standards. Another good aspect of this solution is that your connection is not dependent upon line noise or weather conditions. You can expect high quality transmissions all the time unless there is a break in the fiber backbone somewhere along the network. As an example of cable modem costs, I'll present my own costs for the use of this high speed network. Before I start using the cable modem, I was a normal dial-up user who was paying $19.95 a month to some online service like Mindspring. Add on top of that the $20.00 a month expense of an extra phone line, which was deemed a necessity by my wife who was tired of fighting to use the phone, the cable modem becomes a great alternative. I live in a rural community just north of the Maryland state line in Pennsylvania. The cost of my cable modem is $49.95(http://www.planetcable.net/pricing.asp) month and the speed is 500Kbps. Compare that to the $39.95 I was paying previously for my 33.6Kbps dial-up connection. Another great thing is that $49.95 is considered somewhat high for cable modem service. In Maryland, the charges top out between $39.95 and $44.95. The big downside are the current installation costs. Installation is required by the cable company because the main TV cable line needs to be split off and filtered. This issue is constantly being worked on by cable companies to try to bring installation costs down. Installation costs in my area have just dropped to $99.00.
Cable Modems: How Does it Work?
Cable modems work in a couple of different modes. There are the two-way communication systems, which are normally the $44.95 systems, and there are the phone return systems which rely on a telephone modem to send information from your computer to the service provider. The reason some people use the latter version is simply costs. It costs $29. 95 a month here to use the dial-up return system where I live. But for pure speed and reliability, you still want the two-way communication version. As I mentioned before, to use a cable modem you need a network card in your computer. The network card connects to the cable modem via a twisted pair network cable. The cable modem is also connected to a coaxial line from the cable TV box outside. On one end of this coaxial cable, there is a small filter that is installed by the cable company to keep transmission speeds to 500Kbps. This coaxial cable actually comes from a power splitter from the "old" cable you use for your television signals. No television sets are allowed on this new coax segment because it operates on a different frequency than the normal cable television signal (Østergaard 1998-1999). A recent development in the cable modem may end up making cable modem installation even easier. Intel and Broadcom are currently working together to develop a USB version of cable modems that will simply "plug in" to an existing USB port on the back of your computer. The user would no longer be required to open the case and insert the network card. Although some people seem concerned by the fact that all the cable modem users on one segment share the same bandwidth, it should be noted that each Cable Modem Termination System ( CMST) normally drives 1-2000 users per TV channel. If more users are required, a new channel is generated by installing another CMST. The CMST is the network device at the server end of your network connection. The downstream data is sent using the framing MPEG transport stream specification and the upstream data from the cable modem to the CMST is arranged in either fixed length bursts or variable length bursts.
Cable Modems: What Does the Future Hold?
With the recent deregulation of telephone services, cable companies have found themselves is a great position to offer digital voice and video conferencing services to their customers. If this happens, telephone companies may fine it difficult to compete with the higher speed networks that offer so many services. AT&T recently announced it's own bid to buy Tele-Communications, Inc; a cable service company. This proposed acquisition is bad news since new estimates put about 2.9 million cable modems in use by the year 2001. By comparison, DSL subscribers are only expected to number around 1.7 million users nationwide. (Steve Rosenbush 1/26/99).
There are a couple of reasons for this difference in the number of users. Cable companies are in the entertainment business and sell the Internet access accordingly to their subscribers. Phone companies are considered to be in the utility service and sell their customers "network access". It might sound simplistic, but people like to be entertained and cable modems come in a more entertaining package. Cable modems also got the drop on the phone companies. Cable companies started selling their high speed services about 18 months prior to the telephone companies releasing their DSL solutions. Phone and cable companies are bitter adversaries in the fight for who controls voice and Internet access (http://www.wired.com/news/news/technology/story/19340.html ). Some phone companies have begun offering free Internet access to their long distance subscribers. In response, some Internet providers have teamed up to produce a new protocol that will allow high quality voice to traverse the Internet. If all works out, they'll begin offering high-speed voice services soon. Although this war will probably wage on for some time, Cable Modem companies are outpacing the phone companies. By the end of 1998, cable modem installations had outpaced the high-speed DSL telephone installations 14-to-1 (http://www.wired.com/news/news/business/story/17749.html "Cable Modems Boom"; 5.Feb.99, Reuters). By comparison, over 700,000 cable modem installations took place in 1998, whereas only 50,000 high-speed telephone installations had occurred. There is a down side to all of this, though. Phone companies and Online services have both approached the government asking that cable companies be forced to share their networks (Reuters 1999). In the request, companies like America Online would have access to the cable networks to offer their service as a competitor to the cable company's own Internet service. This effectively removes any motivation for online services to upgrade their networks, since they can just use the networks that the cable companies paid to get installed. Even worse is the idea that cable companies who upgrade their network to provide superior service to their own Internet users would also be upgrading users of their competitors. The request was denied, but the FCC says it will continue monitoring the situation.
Cable Modems: User Concerns
Cable modems provide a great method for achieving high rates of speed on the Internet, but there are a few issues that need to be thought through by the subscriber. Home users have varying levels of Internet use. Lower levels of use may indicate that the cost of purchasing cable modem service is not worthwhile. Users who utilize the connection more often may find it cost-effective. This is especially true when considering a second phone line purchase for a dial-up Internet connection. Cable modems aren't really modems at all. They are network devices that make the users computer part of a local area network segment. Users on a network can access other systems on the network if security is not implemented correctly. For instance, if you use the Windows operating environment and your cable modem service has not shut off the NetBios ports on the network (ports 135-140), then other windows users may be able to browse your computer. It's normal for services to disable NetBios ports, but you should be aware of it. Ensure that you have disabled all default hard disk shares because this would enable users to access your hard drive. Consider installing a simple personal firewall. There are a ton of small firewall products for home use that will block out the curious network user. Always use a virus scanner because virii always pop up when you least expect them.
Cable Modems: Summary.
The Internet has really grown in the last ten years. As more and more users log in, they find that a higher speed connection enables them to do more, process faster, and experience more. Technology is constantly evolving and now we find ourselves in the midst a war for control of high-speed Internet connections. Cable modems provide a great method for achieving this new speed. There is tremendous competition for cable companies. Most of it stems from the telephone companies who are researching new ways to utilize their older technology. If the telephone companies can find a suitable method for providing high-speed access over their current network, and at a reasonable price, they will be a formidable force. But as it stands now, cable companies are winning the high speed Internet service war. The odds for the telecos don't sound so great at 14-to-1, but don't count them out because they are trying to sway the government into seeing thing their way. Should that happen, the face of home Internet service will change drastically.
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