How can I do congestion control for a UDP protocol?

Question

I have a custom UDP protocol with multiple senders/receivers designed to send large files around as fast as possible. It is client/server based.

How can I detect conge

Answer 1

Flow control is an inherently difficult problem because all you really know is when you sent a packet and when you received a packet. Things like latency, loss, and even speed are all statistics that you have to calculate and interpret.

The following article discusses these statistics and their meaning in depth: DEI Tech Note 0021: Loss, Latency, and Speed

Finding a good solution has been the subject of much research and much commercial endeavor. Different algorithms (TCP, UDT, Multipurpose Transaction Protocol, etc.) use different methods and make different assumptions, all trying to figure out what is going on in the network based on the very sparse data available.