# Curious about TCP congestion control

## DigitalCorpus

I have my gentoo box setup as a server on my LAN and to the outside world. I happen to be a lucky individual who has Verizon's FiOS installed on their block so I moved my folks off of dialup to it. I do not have any sort of regular traffic to my server right now, but I'm interested in knowing if any of the available TCP congestion control algorithms available in the kernel would behave the best on my 15/15Mbps connection. By best I mean lowest latency, fastest slow start, most fair, and highest throughput. I know that in the real world, not all of this can come true. I live in California and I do have a few friends overseas in Europe and Africa which kinda throws a wrench into things due to latency as I'd like to give them the best possible connection too.

Thanks in advanced. I tried googling this but I cannot find many explicit details, just theoretical workings and how congestion control affects 100+ megabit or greater transcontinental connections  :Confused: 

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## alex.blackbit

to my knowledge there is no good rule of thumb which algorithm to use.

just try them out. objective measuring is difficult, think about some scenarios.

please be nice and post your results here.

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## DigitalCorpus

Would you mind directing me to a few useful capture or monitoring programs? From what I've read so far, I'd need to measure packet rates, bandwidth utilization, and RTT to start with. I use iftop for basic monitoring of my interface, but its response rate is very slow so I know I cannot use it.

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## alex.blackbit

for RTT a simple ping should be sufficient.

bandwidth testing can be done with iperf.

i am not sure about packet rates, but it would indeed be an interesting thing to measure.

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## ScarletPimpFromHell

Mate, defining and implementing a QoS (Quality of Service) policy is quite a difficult and lengthy process. To be honest I'm having trouble believing you really need a bandwidth policing stategy ie Congestion Avoidance with a synchronous 15 MEG circuit !!!

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