Osi Model Checkpoint

CheckPoint: OSI Model

• Describe the OSI model and how it relates to a network in 200 to 300 words. Your response must include answers to the following:

o On which layers of the OSI model do WAN protocols operate? o What are some of these protocols? o On which OSI layers do switches and routers operate? o If routers reside at more than one layer, what is the difference between the OSI layers?

When one looks at the seven layers of the OSI model, one can determine that layer three is where the WAN protocols operate on. Layer three is known as the Network Layer. The Network Layer performs several routing functions and detects end-to-end addressing and routing datagram’s. The Network Layer can also execute other tasks such as fragmentation, reassembly, and account for delivery errors. There is a unit known as the brouter that some layers contain which performs as a router, and a bridge. The routers and switches function on layers two, three and four. These layers are the Data Link Layer, Network Layer, and Transport Layer.

The Data Link Layer offers the function to move data between networks and make corrections to errors that could possibly occur during the Physical Layer. This layer was meant for point-to-point and point-to-multipoint media characteristics of a wide area media in the telephone system. On the third layer which is the Network Layer, the addressing and routing is executed. One of the best known examples of the Network Layer is the IP (Internet Protocol). On the Transport Layer of the OSI model is where the flow control and the error handling is achieved. An example is the Transmission Control Protocol (TCP). On the Session Layer, the assemblies, and synchronizations are complete.

Regan, P. . Wide area networks. New Jersey: Pearson Education, Inc.