Chapter 6, Problem 1RQ

Program Description Answer

The lowest layer that includes both wired and wireless transmissions on same protocols in an OSI model is layer 3.

Hence, the correct answer is option “B”.

Explanation of Solution

Layer 3:

• In OSI model, network layer is also termed as Layer 3.
• Network layer is used to deliver the messages from source to vital destination.
• Network layer protocols transfers the message from source to destination.
  • It delivers the message from end-to-end.
  • It provides a universal addressing scheme for all nodes in the network and every node should use the same addressing scheme.
  • It provides a guarantee in the delivery of message in a point-to-point connection with the help of data link layer.

Explanation for incorrect options:

Layer 4:

• In OSI model, transport layer is also termed as Layer 4.
• The purpose of transport layer in OSI model is to provide the reliable transfer of data between two processes in the computer.
• This layer ensures the error free delivery, no loss of data, and duplication.

Hence, the option “A” is wrong.

Layer 2:

• In OSI model, data link layer is also termed as Layer 2.
• It makes the transmission of data reliable provided by the physical layer.
• For reliable transfer, it divides the data into data frames and transmits through the communication channel.
• At the destination, it checks for the transmission error and send the acknowledgement to the source.

Hence, the option “C” is wrong.

Layer 1:

• In OSI model, physical layer is also termed as Layer 1.
• Physical layer is used for structuring the undefined data or information over the medium.
• It defines about the interfaces related to the physical medium.

Hence, the option “D” is wrong.