Tursiops_G
Technoid
Premium,MVM
join:2002-02-06
Norwalk, CT
clubs:
 ·Optimum Online
2 edits | [OOL] (POLL) - What RWIN?
(POLL) What RWIN is "Right" for YOU? (Optimum Online Subscribers ONLY, Please.) 
Choosing an "Optimal" RWIN, or Receive WINdow (See: »www.speedguide.net/read_articles.php?id=157 ) isn't as simple as it seems... There are SEVERAL factors that affect Optimal RWIN size (Latency, Packet Loss, etc.), and they are Not Consistent for ALL OOL Subscribers... There is NO "One Size Fits ALL" Answer.
Poll
For those of us who have "Tweaked" their Optimum Online (OOL) connections - What RWIN setting have you found to be the "Overall Best" for YOU? |
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view results · flash pie chart
UPDATE: If your RWIN is 321200 or Greater, AND you subscribe to the 30/2 "BOOST" Service, PLEASE include the statement that you have BOOST Service in your reply as well... Thanks!
-Tursiops_G.
--
If You're Unsure, "RTFM"... If You're SURE, "RTFM" Anyway. |
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RMJLK
join:2004-09-26
Port Jefferson, NY | excellent poll, I am glad you took the initiative and started this. You are a great asset to this community. |
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plat2on1
join:2002-08-21
Hopewell Junction, NY
clubs: | reply to Tursiops_G
513920 |
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Tradewind
CV Noi Ka Oi
Premium
join:2005-11-08
Marlboro, NJ
3 edits | reply to Tursiops_G
Boost, 30/5, 513920
Having tried all values from about 64240 to 513920*2 I have to say that there is not a whole lot of difference in speeds between them. RWIN was always a multiple of MSS. |
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StreetSpirit
Premium
join:2002-08-13
Roslyn, NY | reply to Tursiops_G
373760
I have BOOST service.
373,760 is MSS (1460) scaled to 256. [ 1460*256=373760 ]
Good poll. |
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StreetSpirit
Premium
join:2002-08-13
Roslyn, NY
·Optimum Online
 ·Verizon Online DSL
| reply to Tradewind
said by Tradewind  :Boost, 30/5, 513920 Having tried all values from about 64240 to 513920*2 I have to say that there is not a whole lot of difference in speeds between them. RWIN was always a multiple of MSS. It's optimum is definitely a multiple of MSS as you said. A lot of people add even multiple but the jury is still out.
In any case 513920 is MSS multiplied by 352, which is an even multiple of MSS. 
Cheers
Dave |
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Irish Shark
Play Like A Champion Today
Premium,MVM
join:2000-07-29
Las Vegas, NV
| reply to Tradewind
You are correct that there is not much of a difference.
When tweaking you want the lowest RWIN that gives you the best, most consistent speeds without errors.
I was working with a gent in the Tweaks Forum who was on a 100mb school line. His RWIN was 64240 and he was pulling 50+mb down. Higher RWINs did not help.
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"You can observe a lot by watching". Yogi Berra |
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Lex Luthor
Premium,Mod
join:2000-09-17
Hicksville, NY
Host:
OptimumOnline
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2 edits | said by Irish Shark :You are correct that there is not much of a difference. When tweaking you want the lowest RWIN that gives you the best, most consistent speeds without errors. I was working with a gent in the Tweaks Forum who was on a 100mb school line. His RWIN was 64240 and he was pulling 50+mb down. Higher RWINs did not help. Probably not true if he was downloading from a distant server.
The RWIN and ping times are related so that 64240 might get him max speed from a server with a 20ms ping, but not with a 100ms ping.
I'd have to dig up the formula, but it's over in the tweaks forum.
I think the optimum thing is to take your max speed, assume about a 75-100ms ping time (so that you can get top speed cross-country) and calculate your RWIN from that.
EDIT: Found it.
OOL standard max speed is 15mbps, let's assume you want max speed at up to 100ms latency.
RWIN=15,000,000bits/sec * .1sec = 1,500,000 bits = 187,500 bytes.
Since the theory is that it may help to make it a multiple of the MSS, the next multiple up would be 192,720.
As Irish Shark pointed out, you want the lowest RWIN that gives you max speed.
Anything over 192,720 is pretty much a waste at 15Mbps unless you download from servers with a higher than 100ms latency often. |
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Irish Shark
Play Like A Champion Today
Premium,MVM
join:2000-07-29
Las Vegas, NV
| Q: Is there an easier way to calculate my RWIN? (#6181)
A: Well, maybe.
It involves clicking the "more details" portion of the tweak test result, and looking down at the bottom right hand side for an entry saying "RTTavg".
Take this value and use it for latency in the formula.
(latency) x 1.5 x (advertised speed in kbps) divide by 8
Example: MSS is 1460, RTTavg is 125ms, and advertised download speed is 1500kbps.
125 x 1.5 = 187.5
187.5 x 1500kbps = 281250
281250 divide by 8 = 35156
35156 divide by 1460 (MSS) = 24.07
Round up to next even number = 26
26 x 1460 = 37960 (Optimal RWIN).
The problem with this is that you are chasing your tail. When you insert the "perfect RWIN" and run a new Tweak Test, the average RTT changes. So recompute and you will get a new "Perfect RWIN".
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"You can observe a lot by watching". Yogi Berra |
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doni87
join:2006-02-14
Bronx, NY | reply to Tursiops_G
What would be my optimum RWIN with 30/2 |
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Irish Shark
Play Like A Champion Today
Premium,MVM
join:2000-07-29
Las Vegas, NV
| said by doni87 :What would be my optimum RWIN with 30/2 Don't want to hijack this thread. Come over here »Broadband Tweaks answer the 11 questions and we can go from there.
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"You can observe a lot by watching". Yogi Berra |
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Tradewind
CV Noi Ka Oi
Premium
join:2005-11-08
Marlboro, NJ
·Optimum Online
2 edits | reply to Tursiops_G
But in the real world aren't there so many things that affect your speeds that it is really next to impossible to measure the affect RWIN has unless you do the measurement under laboratory conditions?
Why can't the OS dynamically adjust the RWIN size based on the current conditions it finds? Isn't that what computers are good at? Always wondered about this. |
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Irish Shark
Play Like A Champion Today
Premium,MVM
join:2000-07-29
Las Vegas, NV
2 edits | 2000 and XP were supposed to make dynamic RWIN changes. Too bad it really never worked. The max RWIN is 65535.
Now I am testing Vista. M$ has done something with the RWIN as I can run Tweak Tests and the RWIN is changing on its own.
I don't know for sure if Vista is doing this or the Tweak Test just does not handle Vista very well. I have used The Doctor and the RWIN is not what is reported by the Tweak Test.
So Vista just might be dynamically changing the RWIN depending on where I surf to.
»/tweakr/block:···a=normal
RWIN was set to 64240.
It changed again. I did nothing.
»/tweakr/block:···a=normal
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"You can observe a lot by watching". Yogi Berra |
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Tradewind
CV Noi Ka Oi
Premium
join:2005-11-08
Marlboro, NJ | Interesting.....
Does it change often or basically the first time you go online until you reboot? |
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Irish Shark
Play Like A Champion Today
Premium,MVM
join:2000-07-29
Las Vegas, NV | I don't run the Tweak Tests that often. But when I do that is what I am seeing.
Both those were just run in the last 10 minutes or so. No reboot since this AM.
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"You can observe a lot by watching". Yogi Berra |
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Tradewind
CV Noi Ka Oi
Premium
join:2005-11-08
Marlboro, NJ
·Optimum Online
| I only clicked on one of your links. Now I see that it did change at least a couple of times.
Looks as if Vista will provide lots more topics of conversation (and debates) here. |
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