Consider an exchange between a client and a server using TCP in the transport layer across an IP based WAN network with the following parameters:

$-128$KB TCP window size is used

$-100$Base$-$T Ethernet used as an underlying technology

$-$ RTT $=70$msec

$-$ assume error free transmission

a$)$ Calculate the throughput that can be achieved with the window size given, ignoring protocol overhead

$-$ I already did this one. The answer is $14,979,657\mathrm{.}142857142857142857142857$ or about $14\mathrm{.}98$ Mbps$.$

b$)$ Now suppose that the TCP window size automatically scales to achieve a higher throughput. Suppose the window size increases to $512$KB$.$ Calculate the new throughput that can be achieved.

$-$ I already did this one, too. The answer is $59,918,628\mathrm{.}571428571428571428571429$ or about $59\mathrm{.}91$ Mbps $($I$\text{'}$m putting these answers here in case someone needs a reference for the following question$).$

c$)$ Now suppose that the TCP window size automatically scales to achieve the highest possible throughput. What is the new window size equal to $($in bits$)?$

$-$ This is the one I$\text{'}$m stuck on$.$ Can someone help me$?$