1. Net 222: Communications and networks fundamentals (Practical Part)
Networks and Communication Department
Tutorial 8: Chapter 2 Data & computer communications

2. 2.3. What is a protocol?
A protocol is the set of rules governing the way in which two entities cooperate to exchange data.
2.7. What are some advantages to layering as seen in the TCP/IP architecture?
Layering decomposes the overall communications problem into a number of more manageable subproblems.
Networks and Communication Department

3. 2.3 List the major disadvantages with the layered approach to protocols. Perhaps the major disadvantage is the processing and data overhead. There is processing overhead because as many as seven modules (OSI model) are invoked to move data from the application through the communications software. There is data overhead because of the appending of multiple headers to the data.
Networks and Communication Department

4. The application layer supports the user.
The data link layer is responsible for:
a. framing data bits
b. providing the physical addresses of the sender/receiver
d. detection and correction of damaged and lost frames
Networks and Communication Department

5. a. Reliable process-to-process delivery: transport layer
b. Route selection: network layer
c. Defining frames: data link layer
d. Providing user services: application layer
e. Transmission of bits across the medium: physical layer
Networks and Communication Department

6. a. Format and code conversion services: presentation layer
b. Establishing, managing, and terminating sessions: session layer
c. Ensuring reliable transmission of data: data link and transport layers
d. Log-in and log-out procedures: session layer
Networks and Communication Department

7. Networks and Communication Department

8. The End
Any Questions ?
Networks and Communication Department