Strange upload slowdown issues - help!

Strange upload slowdown issues - help!
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Subject Author Date
Strange upload slowdown issues - help! finalewiz 03-01-2005
Posted by on March 1, 2005, 8:18 am
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Hi everyone. I'm totally stumped!

I have a Comcast connection in Dallas, using a Toshiba PCX1100
(originally from RR in Oklahoma City). About 4 months ago, I noticed
an issue with my upload speeds (download is a consistent 3200Kbps).
Anytime I upload large files (>2MBs), the upload speed starts out at
250Kbps (as advertised). Within about 2 minutes, it has steadily
reduced itself to a steady 60Kbps or so. It stays there for the
duration of the file, then starts all over again at 250Kbps with a new
file, reducing itself to 60Kbps again, and so on. This is bad, as I
routinely upload large audio files to a studio - usually 80 MB's each
or so.

I've tried this on all three of my machines, one with a brand new
installation of XP SP2. Two machines are 802.11G, the main one is
Cat-5 - no difference. I've tried it with three different FTP clients.
I've tried it with my computer connected directly to the Toshiba
PCX1100. All to no effect. I've done a DSLReports quality of service
test - passes fine. Good latencies, good pings. Everything looks
good. Comcast swears that they are providing the right level of serice
- a steady 256Kbps upload speed that would not be throttled down past a
certain upload size.

All I can see is it might be the modem, or a XP setup issue. Can
anyone shed some light on this? Thanks!



Pure Networks
Posted by Quaoar on March 1, 2005, 12:51 pm
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finalewiz@gmail.com wrote:
> Hi everyone. I'm totally stumped!
>
> I have a Comcast connection in Dallas, using a Toshiba PCX1100
> (originally from RR in Oklahoma City). About 4 months ago, I noticed
> an issue with my upload speeds (download is a consistent 3200Kbps).
> Anytime I upload large files (>2MBs), the upload speed starts out at
> 250Kbps (as advertised). Within about 2 minutes, it has steadily
> reduced itself to a steady 60Kbps or so. It stays there for the
> duration of the file, then starts all over again at 250Kbps with a new
> file, reducing itself to 60Kbps again, and so on. This is bad, as I
> routinely upload large audio files to a studio - usually 80 MB's each
> or so.
>
> I've tried this on all three of my machines, one with a brand new
> installation of XP SP2. Two machines are 802.11G, the main one is
> Cat-5 - no difference. I've tried it with three different FTP
> clients. I've tried it with my computer connected directly to the
> Toshiba PCX1100. All to no effect. I've done a DSLReports quality
> of service test - passes fine. Good latencies, good pings.
> Everything looks good. Comcast swears that they are providing the
> right level of serice - a steady 256Kbps upload speed that would not
> be throttled down past a certain upload size.
>
> All I can see is it might be the modem, or a XP setup issue. Can
> anyone shed some light on this? Thanks!

Try uploading a 20MB file to your Comcast online web storage as a test
since this is completely "in network". [25MB is the current file
limit?] I have always seen maximum possible upload speed doing this;
i.e., on my 256kbps rated upload, 30KB/s +/-. The problem might reside
in your upload destination. When doing this, make sure your other
computers are *not* accessing the internet if you are running with one
IP address behind a router since their activity is shared with yours.

Q




Posted by Warren on March 1, 2005, 12:27 pm
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Quaoar wrote:
>
> finalewiz@gmail.com wrote:
>> Anytime I upload large files (>2MBs), the upload speed starts out at
>> 250Kbps (as advertised). Within about 2 minutes, it has steadily
>> reduced itself to a steady 60Kbps or so. It stays there for the
>> duration of the file, then starts all over again at 250Kbps with a
>> new
>> file, reducing itself to 60Kbps again, and so on. This is bad, as I
>> routinely upload large audio files to a studio - usually 80 MB's each
>> or so.
>>
>
> Try uploading a 20MB file to your Comcast online web storage as a test
> since this is completely "in network". [25MB is the current file
> limit?] I have always seen maximum possible upload speed doing this;
> i.e., on my 256kbps rated upload, 30KB/s +/-. The problem might
> reside in your upload destination. When doing this, make sure your
> other computers are *not* accessing the internet if you are running
> with one IP address behind a router since their activity is shared
> with yours.
>

I agree. Isolate the issue as much as possible by taking out servers you
don't have control over, and networks which may have congested peering
points. And get rid of any other sources of traffic within your own
network.

Keep in mind that if you're trying to download - even just web
browsing - at the same time, there will be acknowledgements that need to
be uploaded. Those packets will cut deep into your uploading capacity.

Now does this happen at all hours? For example, does it do it at 3am,
when your neighbors are all asleep? Or does it just happen when you are
really sharing the upstream with everyone else on the block? It wouldn't
take too many people attempting to stuff the pipe at the maximum
bandwidth before the upstream channel is saturated. And when that
happens, the network favors the nodes trying to send less data over
those that have an endless stream queued-up.

Also, your PCX1100 is an old DOCSIS 1.0 modem; the first generation from
Toshiba. Whatever tech support is left for this modem is going to be
fairly limited, so it's possible that whoever wrote the latest version
of the config file being downloaded to the modem has run into some
quirks that weren't a real issue in the days when the modem was new. So
there is an outside chance that it is a modem issue.

--
Warren H.

==========
Disclaimer: My views reflect those of myself, and not my
employer, my friends, nor (as she often tells me) my wife.
Any resemblance to the views of anybody living or dead is
coincidental. No animals were hurt in the writing of this
response -- unless you count my dog who desperately wants
to go outside now.
Black and Decker cordless landscaping tools:
http://www.holzemville.com/mall/blackanddecker/index.html





Posted by finalewiz@gmail.com on March 1, 2005, 6:26 pm
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Excellent - thank you guys for your input. I will try the Comcast
server upload. Yes, it happens at all hours - very predictable
behavior, too. I am already lined up to snipe a PCX2600 off of ebay...



Posted by finalewiz@gmail.com on March 2, 2005, 1:54 pm
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OK, I FTP'd a large file to my Comcast personal web space. Same
behavior!

Think it could be my PCX1100?



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