Consider TCP over wireless Wi$-$Fi $(802\mathrm{.}11$g$)$ networks operating using the DCF MAC$-$Layer mechanism as per the figure below. The network parameters are as follows:

Data rate is $54$ Mbps $,$ Slot time is $9$mus, DIFS is $34$ mus, SIFS $=16$ mus, the MAC$-$layer Window $($W$)$ is $31$ Slots, the ACK is $14$ byes, and the ACK frame is transmitted at $24$ Mbps $.$ RTS$/$CTS are disabled.

Assuming that there is only single user in the network and is using the network over two$-$hops for skype voice call of an average data packet size is $120$ Bytes. Calculate:

a$.$ What is the total end$-$to$-$end delay

b$.$ What is the total network throughput

c$.$ What is the average TCP congestion window size over this two$-$hop network