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This page is a little outdated as it was wrote around 1999. Old links have been removed now.
Modem Basics
When you access the internet, a modem is used to complete a connection from your computer to your Internet Service Provider (ISP). With dialup modems, the connection
first needs configuring, ( dialup connection number, type of protocol and username and password ). After this has been setup, a successful connection will
negotiate the connection to your ISP, and your connection speed depends upon your line length and quality.
Connecting using Microsoft Windows
Using Windows 95/98 dial up networking is the software used to establish your connection. When complete a small icon is displayed in the system tray,
similar to the one below :
Double clicking on this icon will bring up a window usually showing the carrier speed (line speed) of your modem. This assumes that you have the correct driver for your modem and correct initialization string, if not it will display the serial port speed (the speed at which your modem is communicating with your computer).
Connection via Unix or Linux
There are many desktops and varieties of Linux. SuSe 7.2 uses KDE2 as the standard desktop. With kinternet will see the icon below, once a connection to
the ISP is made:
Right clicking this icon and choosing view log will reveal detailed information about your connection. Here's part of my log below :
The modem initialization string can be seen, as can the serial port speed, compression, protocol, transmit and receive speeds.
Connecting with KPPP (dialup)If you are using Linux with the KDE desktop then the program KPPP can be used to configure your connection. The link below deals with configuring KPPP on Redhat Linux, the configuration for different distributions should be very similar:
Optimising Home Wiring
Improvements in speed can often be gained by disconnecting extension wiring and making sure your dialup modem uses the master telephone socket.
Extension telephones, long extension leads use untwisted wiring and always pick up noise. Avoid using these if possible.
Speed Tests
Speed tests should always be considered an indication only. This is because no web site has infinite capacity and
at any time, it will be running hundreds or thousands of simultaneous speed tests. This will affect its ability to measure and also the route to the web site
is not under your control. It will pass through various other networks and servers and any delay on these networks will affect the overall result. Below
are a few popular site test sites:
Sometimes a slow connection may not be due to your ISP or modem but down to global internet congestion. The following link charts global internet traffic as an index from 0 to 100, where the higher the index, the better the traffic flow :
When you click the above link, you can click on the world map and get a traffic report and statistics for any country in the world. If the index is in green, then everything is OK, amber or red then performance is impaired.
Van Jacobson (Unsung Hero and Inventor of TCP/IP Header Compression
Data to and from your computers modem is transmitted and received in groups or packets. The packets use a protocol (set of rules) called TCP (Transmission
communication protocol) and an IP (Internet Protocol). These packets reach their destination by means of a header block. Each header has 20 bytes and an optional
data field of up to 40 bytes. All this increases the amount of information 'data' that starts to flow, with even a short message. It was in 1985 that an American
computer scientist, Van Jacobson set up two computers in the same room and throughput was about a bit per second. For the next six months Van Jacobson together
with Mike Karels, worked on this problem to solve this speed issue. The result of his work was an update to TCP that uses header compression- without this
compression algorithm sending data from machine to machine would be too slow, and the internet we have today, would never have taken off. On Linux operating
system these packets are shown as VJcomp. You can read more about Van Jacobson in the links section.
Download Accelerators
As the name suggests you can use software programs that try to speed up your internet connection. The average
telephone line has a speech bandwidth of around 4kHz. When data is sent down the line, it does not occupy the
full bandwidth, so there is "room" for more data. Download accelerators work by creating multiple simultaneous connections to the same source, thereby
improving your download speeds. However be careful, because some sites will log your connection and you could get banned from using that site.
One such program called "Axel" is available natively on linux and FreeBSD, a link for windows is below:
Links
Van Jacobson Wikipedia
Van Jacobson in Wired Magazine
TCP IP Headers