init_cwnd anyone

[pmeenan]

Most CDN's and load balancers also already do some level of init-cwnd blasting (they usually call it TCP acceleration).

Is your JSON also served through the CDN? The TCP 3 second slow start default mostly kicks in only during socket connect. After that the TCP stack has an estimate for the RTT and will use that for the basis of it's algorithms (though the actual RTT doesn't really matter for slow start, it's more for retransmit times).

How big are your json responses? Just checking to see if they are something that should fit within a 10-packet cwnd or not. Odds are it will be difficult to convince a CDN to change their settings (F5 you might be able to since it is running on your premises).