anomynous
@fuse.net
| maximizing upload speed?
Just switched from rr to zt to get higher upload speed.
Couldn't get service working initially, service guy came out and removed the MTU?, and while he was here I had him install a POTS splitter. Based upon line tests he did while here (slight packet loss at 3m), I'm configured at 768/2560 through a Westell 6110.
For a while they bumped me up to 3Mb, but one morning I had an outage where the modem wouldn't stay synced, and I told them to leave it at 2560.
With rr's 384k upload, I could get 40-42KB/s. With zt's 768k upload, I seem to max out at 78-80KB/s - ie zt upload is slightly less than double rr's.
Based upon a couple conversations with tech support, I've been told:
1) 80KB/s payload is max I should expect at 768
2) depending on equipment factors (dslam at co?) in some cases they can bump upload to 912 (don't remember exact number) but apparently not in my case (option wasn't available on config screen)
3) I'm in an ADSL2 beta area
Questions:
80KB/s * 8 = 640kb/s
What with IP, TCP, and protocol packet headers, I don't expect to get the whole 768, but does overhead really amount to 1/6th of the available bandwidth?!
Would switching modems help? Is the Westell 6110 bad/fair/good/best? Would switching modem force/trigger a dslam change that would enable the 912 upload?
Also, would pushing to be included in the ADSL2 beta get me higher upload? Note that I am less concerned with higher download speed than I am with upload speed.
Thanks! |
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schmattie
join:2003-07-20
Florence, KY
edit:
January 6th, @01:18PM
| Switching modems will not help. Maximum upload on any ZT modem is between 78k and 85k. Your math is a bit wrong on how to calculate bit rate with an internet connection.
Connection speed is determined by this calculation:
((Bitrate * 1000)/1024) * ((Maximum transmission unit with overhead)/1500)/8 = transfer rate in KB
Bitrate would be 768 for example.
You multiply by 1000 because it's actually 768,000 bits
you divide by 1024 because there are actually 1024 bits in a kilobyte.
Now the Maximum transmission unit for a dsl connection is smaller than a cable connection because ADSL has more overhead. Zoomtown is PPOA, (Point to Point Protocol over ATM) which results in about 12-15% overhead. The MTU for a cable, DSL, BPL, T1 etc is 1500. So 88% of 1500=1320 and 85% of 1500 =1275. So your maximum Transmission unit is actually around 1300.
So using your info your upload speed would be....
768* 1000 = 768000
/ 1024 = 750
* 1300 (MTU/w overhead) =975000
/1500 (MTU) = 650
/8 (bits per byte) = 81.25
Now that I have bored you. I can tell you that your download transfer rate is about 268-270 kbs.
Also ADSL2 is DMT only. Meaning no Cisco675 for you! The programing in your DSLAM is what allows for higher synced rates ie 1024. I'm guessing you are in West Chester? If is is not in the DSLAM already your DSLAM may not be compatible. You are probably on a Cisco 6100 or 6400 (I can't remember) Hopefully your are not on a pedestal. I doubt you are on a Lucent Anymedia as they can sync @ 10240 / 1024.
anyways...good luck |
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anomynous
@fuse.net
| I'm through the Cresentville CO.
And the bottom line on your calcs, including your statement "Zoomtown is PPOA which results in about 12-15% overhead" is that yes, 1/6th (= 16.7%) is sucked up in overhead.
Yeah the impression I got from one of the tech support folk was that being able to go faster depended upon the dslam, but I just wanted to be sure it wasn't related to the modem on my end.
Thanks! |
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viper453
join:2003-03-30
Cincinnati, OH
edit:
January 8th, @01:19AM
| well with zoomtown it depends what they have you trained at, they have me trained at 3072/952 kbits/sec. my real speeds r 322 kbytes/sec down and 102 kbytes/sec up. i think they either train ppl at 3/818 or 3/952 when i had 818 upstream my up was around 87 kb/sec.
it's alot different with cable internet road runner trains everyone at a standard 5/384 cable has less overhead so u get more speed 5 mbits cable is around 600-620 kb/sec and 45 kb/sec upstream road runner extreme is even faster a whopping 8 mbits down and 512 kbits upload whitch is much slower upstream than what i get with ZT but download is 3 times faster at a blazzing 950-980 kb/sec. |
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anomynous
@fuse.net | they have me trained at 3072/952 kbits/sec
What CO and what modem?
Thanks! |
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viper453
join:2003-03-30
Cincinnati, OH | i think i use the price hill co, and i use cisco 675 Zt has been using it from the start hehe. problem with the cisco router it's max is only 7100/1088  |
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qnadad
join:2004-05-30
Covington, KY
| reply to anomynous
3) I'm in an ADSL2 beta area
Sorry this is wrong. If you were in ADSL2 beta area you would be getting more than 3meg. If all you got was 3meg, you're still ADSL1. Most likely you are in a beta area for speed testing purposes. To my knowledge, from talking to people that I know, Bell isn't ready to deliver ADSL2 to consumers yet. Not sure if it's a technical issue or whatever, it's just what I heard.
The MTU for a cable, DSL, BPL, T1 etc ethernet is 1500.
There, fixed that for you.
problem with the cisco router most ADSL1 modems it's max is only 7100/1088
There, fixed that for you |
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cincyguy2k4
@fuse.net | When did you get the upgrade? I have been waiting to hear about news of the ADSL2 for a while. |
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cincyguy2k4
@fuse.net | reply to anomynous
When did you get the ADSL2 upgrade? I have been waiting to hear about that for a while. |
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buch3r
join:2005-08-13
Cincinnati, OH
| reply to anomynous
According to the westell modem browser, my 6110 is connected at 3072/768, and I get exactly 83.3% of that speed. 3072/8=384, and my max download is 320kb/s, 768/8=96, and my max upload is 80kb/s. How do you get them to have you train at a higher upload rate? Also, schmattie, are you saying I should change my MTU setting and RWIN accordingly, or leave it at 1500? |
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Wiggles45
join:2006-02-01
Casstown, OH | reply to anomynous
woot if anyone lives in the harrison area tell them to up u to 2.5 or 3.0 if u arent cause my speed is running at 2.5 its just now my modem is stopping me from going further but ya |
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