15.566:
INFORMATION TECHNOLOGY AS AN INTEGRATING FORCE IN MANUFACTURING

SPRING 1998

Technology Exercise #1: EXPLORING THE INTERNET

Windows 95 and NT 4.0 provide a utility program that helps trace the route that connects your computer to any other computer on the Internet. The program is called tracert (stands for "trace route") and must be called from inside an MS-DOS window. The syntax for using tracert is:

tracert <destination-host-name>

The results of executing tracert is a list of all the Internet nodes (i.e. computers visited) in the Internet path that connects our computer to the destination computer. For example, the result of executing:

tracert www.stanford.edu (a computer at Stanford University)

from bakos.stern.nyu.edu (a computer at New York University's Stern School of Business) is the following list of nodes:

By studying the list above, you can find useful information such as

• what is the gateway of NYU to the external world?
• who is operating the backbone that connects the networks of NyserNet and BBN Planet (two Internet Service Providers)?
• is there a direct connection between New York and Palo Alto? If not, what are the intermediate hops?

By comparison, executing tracert www.stanford.edu from bakos.mit.edu (a computer in the 3rd floor of building E53) gives the following list of nodes:

Figure 1: High-level structure of the Internet, showing LANs, gateways, regional networks and backbones.

The purpose of this homework is to give you the opportunity to use tracert to explore small parts of the structure of the Internet. The experience will help you get a better sense of how the various elements of the Internet connect together (see Figure 1).

Task: Use tracert to the appropriate destinations in order to answer the following questions:

1. What is the name and IP address of the gateway of MIT to the external world?
2. Who provides the regional network that connects MIT to the rest of the Internet?
3. How many long-distance data communications providers (like Sprint or NyserNet) are involved in getting data from NYU to Stanford? What about MIT to Stanford? Which connection (NYU to Stanford or MIT to Stanford) is likely to be faster?
4. Where is the company site of Texas Instruments (ti.com) physically located? Who provides the backbone that connects together MIT and the location of ti.com? What U.S. cities are visited by packets on route from MIT to ti.com?
5. Which major cities are visited on the Internet route from MIT to www.uci.edu, a computer at the University of California, Irvine? Who provides the backbone for this route? There is a switch between networks of different providers along this route. Which nodes act as the bridge between the two networks?
6. Which are the gateway cities in the U.S. and Germany (i.e., the cities where packets enter/exit the country) that are visited by packets on the Internet route from MIT to www.siemens.de, a computer located in Germany? Which company transports packets under the Atlantic between MIT in Cambridge, MA and www.cambridge.edu, a computer located in Cambdridge, UK?