Question

assume a five layer network model. There are 700 bytes of application data. There is a 20 bye header at the transport layer, a 20 byte header at the network layer, a 14 byte header at the data link layer and a 4 byte trailer at the data link layer. Calculate the percentage of the bytes sent to the physical layer that is overhead.

Answer 1

Answer: The overhead percentage is 7.7%.

Explanation:

We call overhead, to all those bytes that are delivered to the physical layer, that don't carry real data.

We are told that we have 700 bytes of application data, so all the other bytes are simply overhead, i.e. , 58 bytes composed by the transport layer header, the network layer header, the 14 byte header at the data link layer and the 4 byte trailer at the data link layer.

So, in order to assess the overhead percentage, we divide the overhead bytes between the total quantity of bytes sent to the physical layer, as follows:

OH % = (58 / 758) * 100 = 7.7 %