$(18$ pts$)$ Consider a four$-$layer protocol implementation with application, transport, network, and data link layers, in

that order $($top to bottom$).$

The application layer does not add a header. The transport layer adds a $20$ B header. The network layer does the same.

The data link layer adds a $48$ B header and a $2$ B trailer.

Answer all of the questions below. Show your work.

a$.(4$ pts$)$ Assume that the data link layer has a maximum transmission unit of $1550$ B$.$ Determine the number of frames

created by this layer for transmission of a $1500$ B message from the application layer. Frames are not padded.

b$.(7$ pts$)$ Draw the frame or frames created by the data link layer for transmission of this message. Identify all headers

and trailers for each frame. Label each header or trailer with its length in bytes and the name of the layer that added

it$.$ Clearly identify the data link layer payload and determine its length.

c$.(4$ pts$)$ Calculate the total overhead $($percentage$)$ associated with transmission of the $1500$ B message. You can leave

your answer in fractional form, as long as you clearly show how you calculated the numerator and denominator,

respectively.

d$.(3$ pts$)$ Assume that the next downstream link has a data link layer MTU of $2050$ B$.$ Will any further fragmentation

happen? Why or why not?