WWW Traffic

WWW Traffic
All WWW traffic starts from somewhere, so assuming that you are connecting to the Web via
your LAN, that’s the first place where problems can affect the connection and the upload or
download speed.This is just a small part of the story, however. The weakest link in a chain
always sets the strength for the whole chain, and the same is true of networks. So as far as transfer
speed is concerned, we need to spend most of our time working on the narrowest bandwidth
(generally the lowest speed). And that is unlikely to be the switched Ethernet LAN.
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Chapter 20 
Quality of Service (QoS)
After all, your LAN is probably running 100BaseT, switched, possibly with duplex links to
important machines. The connection to the Internet is probably through the company firewall
(a packet-filtering engine introducing its own delay), and the Internet speed itself available to
your PC is probably be a fraction of an E-1 or T-1 at best!
Obviously, if the service runs too slowly to be of use, and if you can identify the
switched Ethernet LAN that you are connected to as the choke point, then you
need to do something about it. But for the moment, let’s leave the problems
with WWW to the WAN guys.
What is important to us is that the size of each WWW packet may be different. Even though
we tend to equate being connected to a website as having a single flow, that is rarely true. The
construction of modern websites and the surfing behavior of Internet users means that TCP sessions
are being opened and closed all the time, and the download of different format content
ensures that the service is very patchy (see Figure 20.2).