5 Layer Model

Question 1

Physical

Answer 1

1) Transceiver drives signals on the network
The physical layer transmits the raw data. It consists of hardware such as switches and routers. The layer deals with all aspects of setting up and maintaining a link between the communicating computers.

Question 2

Data Link

Answer 2

2) Creates frame that moves across networks
The data link layer sends data from the network layer to the physical layer. It divides the data to be sent into data frames. A data frame consists of a link layer header followed by a packet. The data link layer handles the acknowledgements sent from the receiver and ensures that incoming data has been received correctly by analysing bit patterns in the frames.

Question 3

Network/Internet

Answer 3

3) Creates Packets
The network layer is responsible for the addressing and routing of data. Routers belong to the network layer as they use logical addresses to direct the data from the sender to the receiver. A router determines the path the data should take based on network conditions.
Routers manage traffic problems on the network such as the routing of packets to minimise congestion of data.

Question 4

Transport

Answer 4

4) Establishes connections between applications on different hosts
The transport layer ensures that data is transferred form one point to another reliably and without errors. The transport layer is responsible for making sure that data is sent and received in the correct order. The transport layer is implemented in the sending and receiving computers but not in the routers on the path between them. It acts as an interface between the communicating computers and the network.

Question 5

Application

Answer 5

5) Applications requiring network communications
The application layer provides interfaces to the software to allow it to use the network. Examples of software include email, file transfer protocol (FTP) and the World Wide Web (WWW).