ISPs

COMP1260 > Understanding the Internet

Introduction The Internet is an useful tool and an ISP or Internet Service Provider allows us access to it. Today the options for how to connect to the Internet are vast and diverse. This article will give you a general feel of the evolution of ISPs from Dial-up to wireless technologies. Also, some basic detail of what makes each type of ISP unique will be provided. We will begin at the beginning with the Dial-up Internet service.

...by students I can remember when my dad first brought home a 14.4k modem and we tried to connect to the Internet. At the time I hadn't even heard of the Internet but my dad worked with the University of Manitoba and had a free account. We tried to connect. After sitting in front of the monitor for an hour with an ungodly sound coming from the modem I got bored and left the computer and my dad took over trying to connect. When I returned later that night we were connected! What was on the screen was the website for the University, which at this point consisted entirely of text. Next we tried to connect to another site and lost our connection. For years this was what the Internet was for me. It really is amazing how far we have come. </td> </tr> </table> Dial-up Dial-up was one of the first technologies allowing us to connect to the internet. Dial-up relies on pre-existing telephone infrastructure(e.g. phone lines and towers) and offers a top speed of 56 Kbps. A modem is used to turn the data sent into a signal that can be sent over the telephone line and the reverse is true of received signals. The connection is always active, meaning the phone line is entirely dedicated to the internet and no phone calls can be made out or received from this line. A second line must be put in to both be on the Internet and make or receive calls. Today many carriers of Dial-up offer high speed access. The 56 Kbps limitation still exists but what makes this service faster is the compression of the information being sent/received. This could be compared to zipping or compressing a file in order to make it smaller, this same principle can be applied to web content. Dial-up is still used today in rural areas where faster alternatives simply aren't available. Unfortunately Dial-up simply is not fast enough today, as even basic websites increase in size. Picture of 14.4K modem taken from http://www.flickr.com/photos/bike/3191084319/ DSL DSL (Digital Subscriber Line) is the next evolution of the tradition Dial-up service. DSL still relies on pre-existing telephone infrastructure and the use of a modem. DSL however, offers faster speeds and concurrent phone and Internet service. This is accomplished by taking advantage of the true potential that a phone line possesses and dividing up all the frequencies that are used by the signal sent over phone lines. The first 4 KHz of the available frequencies are used for traditional phone service, 4-50KHz are used for the uploading of data and the remaining 50KHz-1MHz of the line are used for downloading. As you can see the segment allocated to uploading is smaller than the downloading segment, something you may have personally experienced. Speeds can reach up to 1 Mbps for uploading and 8 Mbps for downloading. Cable Cable like DSL and Dial-up utilizes another technology and pre-existing infrastructure. Cable uses the same lines that are used to provide cable television. Speeds can be up to 30 Mbps for downloading and 2 Mbps uploading. At first glance these numbers seem much higher than that of DSL but it is more complicated than this. Signals are sent over hybrid coaxial cables to a router, which is essentially a relay station for the information that is being passed. With cable Internet, access to the router is shared amongst a set of cable subscribers in a geographically determined area. On the other hand DSL users have dedicated access. So if you are in an area with many active cable subscribers you may experience slower than normal speeds. Wireless Technology Wireless technologies allow computers and other devices to access the internet through the use of radio signals. The data that is being sent is translated into a radio signal and sent to a wireless router where the signal is decoded and put on a physical wire out. The use of radio signals means that there are geographic limitations. Because of the curvature of the earth radio signals can cover only a limited area. One solution to the issue is simply to build the towers which provide the internet access higher. The area where a wireless internet connection is available is often referred to as a hot spot. Wireless is a popular option in rural areas without DSL or Cable connections because of the greater speed. For remote locations a satellite connection may be your only option to connect to the Internet. Satellite Internet Another option for accessing the Internet is to use a satellite Internet provider. Like other forms of wireless technologies satellite transmissions have some limitations. If there are too many clouds in the sky or if it is raining for example, you will not be able to access the Internet. Satellite also additionally requires that you have a dish or antenna. Satellite remains to be popularized because of the high costs associated with the service. Further Readings http://en.wikipedia.org/wiki/Internet_service_provider http://www.theispguide.com/isp-connection.asp References Previous Page: Who Manages the Internet? Next Page: Domain Names, IP Addresses and URLs