Case Project 2­1 Despit the token ring having some of the same fundamentals as Ethernet, such as having a MAC address and sending packets, they are very different. The thing that separates the two network technologies are how they avoid packet collision, that is when a device is both transmitting and receiving at the same time­ which keeps it from actually receiving the intended signal. Ethernet listens for information before transmitting a packet. This is done because there is a one to one connection between transmitting nodes; they pretty much talk with each other. A token ring, on the other hand, avoids this by transmitting extra information called a “free token” which addresses a packet to a certain node. This packet is then passed on through nodes in the ring who forward the token and packet, until it reaches the right node, much like the mail service. By changing the NIC’s setting you also changed how it reads packets. It is expecting to read a Ethernet packet, but instead it gets a token ring packet with information it cannot understand.

Case Project 2­3 The student should care about data frames and the OSI model because they are the digital and theoretical forms of the information sent by the network. Without data frames there would be need for switches and cabling because there would be nothing to propagate, and without OSI there would be no clear model for how to interface the physical assets and the digital packets. If the student was interested in routers he would need to start by looking at the Network layer for OSI, and he should also look at the IEEE 802.1 standards for concrete implementations of the OSI model. The OSI model is useful for debugging because of the clear separation of responsibilities for each layer. There is no redundancy, so you can easily isolate a problem. Also because the previous steps only add information without changing the previous information you can find the error without having to waste more time going through extra data. If your data was not encoded properly you would look at the presentation level because it is the only one responsible for formatting and encryption.