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 funchordsHelloPremium,MVM
join:2001-03-11
Yarmouth Port, MA
kudos:5
1 edit | reply to axus
Re: No Clue said by axus:But, the TCP stream issue still comes into play when you have two people who are maxing out their 5/1 connection. User #1 has 11 TCP streams, 500kbit/100kbit each. User #2 has 1 TCP stream, 5000kbit/1000kbit. What happens when each drops a packet? User #1 has one stream drop to 250kb, the rest stay at 500. User #2 has his whole stream drop to 2500k/500k, while #1 is now at 4750k/950k. The algorithm will ratchet them back up, but packets are still going to be dropped. THANK YOU!!! THANK YOU!!! Finally, someone who understands how this works!!
Two comments that I have to make quickly (time to go to an appt):
1. This "unfairness" only happens when the network is congested. What you're seeing here is a "keep the network alive" recovery method (prior to this, the network would continue to grind to an increasingly slowing stop). A healthy ISP or transit network does not run at congestion on a constant basis -- during the busiest hours of the busiest days, maybe a few times. So George Ou is concentrating on fixing a "fairness" problem that occurs during a network exception -- this is a rather dumb thing to spend a lot of time on.
2. "Fairness" really isn't the problem at all. Regardless of how you slice the allocation during congested moments, the problem to solve is avoiding reaching that moment of congestion. Even if you implemented every suggestion that Bob B. and George are making, you will not have addressed ANY of the issues allegedly causing congestion in the first place.
--
Robb Topolski -= funchords.com =- Hillsboro, Oregon
"We don't throttle any traffic," -Charlie Douglas, Comcast spokesman, on this report. | |
 knightmbEverybody Lies
join:2003-12-01
Franklin, TN | Everyone has to keep in mind, this is from the standpoint of a single IP address. When you sit behind a NAT router with multiple computers using the Internet from an access point of either DSL, T1, Cable, etc. then all of the problems you experience are the limitations of NAT.
Try this same experiment with two separate IP address on the same link and you'll notice the problem goes away. You can have a 1 MB/s Up and Down link (just for easy math reason) and if you have 1 IP address with a NAT sitting in front of it burning all the bandwidth available, then yes the issues of sharing come into play. But if the same link had 2 IP address in which they both shared that 1 MB/s pipe, and 1 IP address was maxing out the link with 1 or 100 connections, the other IP address would still get exactly half of the bandwidth for it's one single connection it had going. TCP/IP is suppose to work properly from IP address to IP address, not IP address to self.
The NAT router is no different that one computer with one IP address having to determine what takes priority over what. When you don't have any traffic shaping or QoS on the NAT, then yes it's first come first serve because that's the whole limitation of using NAT to share multiple computers behind the same IP address.
When they wrote the TCP/IP stuff decades ago, they didn't have to worry about NAT routers and how it changes the rules. | |
funchordsHelloPremium,MVM
join:2001-03-11
Yarmouth Port, MA
kudos:5 | said by knightmb:But if the same link had 2 IP address in which they both shared that 1 MB/s pipe, and 1 IP address was maxing out the link with 1 or 100 connections, the other IP address would still get exactly half of the bandwidth for it's one single connection it had going. What you are describing here is the proposal from Bob Briscoe and George Ou. I say proposal because it (reportedly) does not work as you are suggesting it does.
Are you saying that you've run a test that shows otherwise? If so, please describe your test environment (some stacks behave differently than others). Maybe we can figure out why the results came out like that.
said by knightmb:TCP/IP is suppose to work properly from IP address to IP address, not IP address to self. I don't understand this final line at all. Can you rephrase it?
said by knightmb:When they wrote the TCP/IP stuff decades ago, they didn't have to worry about NAT routers and how it changes the rules. Two responses to this:
1. TCP definitely has been revised since RFC 793. In so much as each revision changes the protocol somewhat (aka an "update"), it's not exactly fair to say that NAT hasn't been considered.
2. (And now to contradict myself,) NAT is not yet an Internet Standard. Various implementations of NAT to not play the same -- some do not play well together. So what NAT does, or what TCP does across a NAT device, probably varies.
--
Robb Topolski -= funchords.com =- Hillsboro, Oregon
"We don't throttle any traffic," -Charlie Douglas, Comcast spokesman, on this report. | |
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