When you have large link Bandwidth Delay Products such as in satellite links, TCP slow start and the default kernel socket and TCP config becomes an impedance to performance - often causing overshooting of available link bitrates resulting in significant packet loss; retransmitting over such links is quiet costly. TCP HyStart (on by default in the kernel), intended to avoid overshooting during slow start, unfortunately often exits from slow start prematurely which is especially detrimental to utilization on large BDP links.

In this talk Maryam Ataei Kachooei et al propose adjustments to slow start that find a safe point to enter congestion avoidance (CA) without overshooting, while also avoiding premature exiting of the CA. They will discuss their socket tuning and their kernel modifications to achieve the stated goals. And finally they will discuss their evaluation and results of their proposed slow start algorithm over: 1) a commercial geostationary satellite link, 2) a low orbit satellite link and 3) a wired link.

cheers, jamal

PS: About one week before ReelCheep early bird registration ends.