Wireshark is an extremely versatile and useful tool. However, there are some things it doesn't do easily or at all, so we'll discuss a few other tools you may want to include in your analysis toolset.
HttpWatch is a packet-based performance analysis utility that integrates with Internet Explorer and Firefox browsers to view a graphical depiction and statistical values from HTTP interactions between the browser and websites. This kind of utility makes it easy to discover and measure from the user's perspective when significant delays are occurring and the source of those delays.
The following screenshot shows the HttpWatch visual and numerical analysis by loading the www.wireshark.org home page:
You can get more information about HttpWatch from http://www.httpwatch.com/. Also, a similar performance analysis utility is Fiddler, which can be found at http://www.telerik.com/fiddler.