Case Project 2-1 Page 73

Case Project 2-1 Page 73

You are a networking professional who works in a college computer lab. The computers run only the TCP/IP protocol on an Ethernet network and all computers use 3Com NICs. Many beginning computer science students use this lab for homework; you help them access the network and troubleshoot problems with their connections on a daily basis. One day, a student begins tampering with his computer; when he restarts the computer, it alerts him that it can't find the network. He calls you over to help. You ensure all the physical connections are sound. Then, you check the workstation's network properties and find that he has changed the frame type that his NIC uses to transmit data from Ethernet to token ring. Explain why this has prevented the workstation from connecting to the network. Further, explain to the student what types of changes visitors to the shared computers in the lab are allowed to make and why you have imposed such restrictions.

The Network Interface Controller or NIC communicates through the physical layer and data link layer, managing its frame type and transmission responsibilities in a network. Since NIC transmits data from Ethernet to token ring, changing frame type of the NIC might cause an error connection; as to the computer not being able to find the network in this case. Frame types must be unique and cannot communicate on the network with different frame types because the router cannot support more than one frame type in a physical interface. As a result, the computer cannot find the network. I would explain to the student that visitors to the shared computers in the lab are only allowed to make slight changes to the system such as display settings and the like. Students should not be allowed to access anything that requires administrator privileges, and I imposed such restrictions because of safety and security reasons and to protect the network settings.