Lab 12.1.3 Protocol Inspector and TCP

Estimated time: 30 min.

Objectives:

> - Use Protocol Inspector (or equivalent) software to view dynamic TCP operations

Background:

> Protocol analysis software has a feature called capture. This feature allows all frames, through an interface, to be captured for analysis. With this feature, you can see how the Transmission Control Protocol (TCP) moves segments filled with user data across the network. You may have found TCP to be a bit abstract, but with the protocol analyzer we can see just how important TCP is to network processes (such as email and web-browsing).

Tools / Preparation:

> Each PC must be running Windows 95, 98, or NT, Microsoft TCP/IP stack, and Winsock 2.0. Fluke Protocol Inspector ver. 3.0 (or higher) Software (Check the Web for downloadable upgrades) must be installed on each PC. During the installation of the software you must specify which network adapter (NIC, dial-up, etc.) you wish to monitor. Then, specify the NIC that attaches the PCs to an Ethernet. The PCs should be on either a 10BASE-T or 100BASE-TX Ethernet network. Preferably, the network includes servers, switches, routers, and printers and a connection to a web server, or preferably the Internet. (this will make the protocol analysis more interesting). The following resources will be required:

> - PC with Windows 95, 98, or NT, Microsoft TCP/IP stack, and Winsock 2.0.
> - Fluke Protocol Inspector ver. 3.0 (or higher) Software (Check the Web for downloadable upgrades)
> - Browser and email applications installed and running

Worksheet

> 1. Open Protocol Inspector and your browser.
> 2. Go to detail view.
> 3. Start a capture.
> 4. Request a Web Page.
> 5. Watch the monitor view while the web page is requested and delivered.
> 6. Stop the capture.
> 7. Study the TCP frames, HTTP frames, and statistics using various views, especially the detail view.
> 8. Using the detail view, explain what evidence it provides about a) TCP handshakes b) TCP acknowledgments c) TCP segmentation and segment size d) TCP sequence numbers and e) TCP sliding windows.

Reflection:

> Did this lab help you to visualize the TCP protocol in action? Why or why not?

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