Filling A Fat Pipe

A backup job pushes a single TCP stream across a 400 Mbit/s path with a 90 ms round trip time. Loss is negligible and the congestion window is never the limit.

What is the throughput ceiling if window scaling is not negotiated, and what is the smallest window scale shift that lets one connection fill the pipe?

A

Ceiling about 5.8 Mbit/s; shift must be 14, the maximum

B

Ceiling about 5.8 Mbit/s; smallest sufficient shift is 7

C

Ceiling about 5.8 Mbit/s; smallest sufficient shift is 6

D

Ceiling about 0.73 Mbit/s; smallest sufficient shift is 7