Hi WhyLikeThis,

Thanks for taking the trouble to comment on my blog post. You are correct that cwnd unit is indeed in packets.

And the mss of a loopback connection is, as you say, 32K. But here we are concerned not with connecting to other processes on the same server, but routing across the WAN to the other side of the globe. And unfortunately, unless we are able to enable jumbo frames, we are stuck with the historical relic of 1500 packet sizes. This means that the initial congestion window size of only 15K.

Thanks for correcting my error about cwnd units. I'll fix the post later today.