[p2p-hackers] UDP file transfer protocol peer review

[David Barrett]

Alex Pankratov wrote:
> 
> If your protocol allows for RTT estimation, you may try detecting
> a congestion by looking at packet loss _and_ RTT value. If the
> congestion is caused by the software which employs some sort of a
> packet queueing, you will see a noticable increase in RTT at a rate
> that immediately preceeds its maximum lossless value.

A downside of not using per-packet ACKs (or indeed, any ACKs) is that 
there's little opportunity to continously evaluate the RTT.  However, 
you provide good incentive to change the protocol in order to support this.

> IIRC in a simple scenario with two directly-connected Linux boxes
> RTT rapidly goes up 3-4 times before receiving box starts dropping
> packets.

This is excellent real-world feedback.  Thank you.  I'll keep an eye out 
for this.

-david