Local Area Network (LAN)

The University Network

The University of Arizona network is composed of many different computer systems located throughout the university and physically connected to the campus network backbone, a complex series of fiber optic cable and high-speed data lines linked together by a series of specialized computers called routers and gateways.

Routers and gateways are used almost exclusively for routing network traffic from one segment of the campus network to another section of that network. This was demonstrated in the explanation of the traceroute command. Note the lines:

• Pancho.Telcom.Arizona.EDU (128.196.128.1) 0ms 0ms 0ms
• westgate.Telcom.Arizona.EDU (128.196.1.1) 0ms 10ms 0ms
• sl-ana-6-S1/T1.sprintlink.net (144.228.76.5) ...

These are specialized routers whose primary responsibility is to make sure network traffic is routed by the most expeditious means to the next electronic location in the path towards the destination. Over time these links will change, depending on the optimal route and redundant route usage. Note the use of Sprintlink and MCI networks.

The campus network backbone is maintained by the Telecommunications Section of the Center for Computing and Information Technology(CCIT). Generally, each department or college entity is responsible for its portion of the university network and must work closely with CCIT to coordinate network activities.

While the physical view of the university network is complex, the logical view is much simpler. The logical view of the University network allows you to access any computer system on the university network as if it were in your office. For example, if you want to send E-Mail to an individual who uses a computer system in Electrical Engineering, you simply address your E-Mail to that individual and computer system. If you want to connect to a computer system at the CCIT (and you have authorization) you simply issue a command from your desktop and you are connected.

Logically, all you have to know is that the computer systems are connected via a data communications network. The following illustrates a small portion of how the logical university network might look for an application using BPA, CCIT, and the Engineering Department's network.