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Posted by Jbob on June 29, 2005, 8:19 pm
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>
> Do your speed tests at 0-dark:30; 4:00am is good since you can guarantee
> that no one else is sharing the line. I've been using www.testmy.net for
> testing. It is less busy and more consistent than speakeasy. Do your FTP
> tests show full upload speed?
The time of my speed tests so far has been been negligeable. I find it
really has no bearing on results. When I first discovered this issue it
seemed to be worse during the day but lately it is very random night and
day. While I do find Speakeasy fairly reliable I use others as well like:
http://jlab4.jlab.org:7123/
http://netspeed.stanford.edu/
Mostly I use WS-FTP LE to do my upload testing. I upload files to my
Personal Web Space on Comcast. I figure that is the best way to gauge
speeds anyway. I use the speed dialog shown during transfers to gauge my
upload speed but also monitor using the small app NetPerSec. It allows for
finer details. One of the things I see is during an upload NetPerSec will
show the transfer actually stop for many seconds. It also shows the speeds
fluctuating wildly during transfers during those periods when there is a
problem. When my problem is not currently presenting itself my uploads
speeds fly, averaging over 700 kbps. During these periods of bad upload
speeds my download speeds usually do not suffer and speed tests show my
downloads at or near my max of 6000 kbps.
> Access your modem web interface and report the text for both upstream and
> downstream. You might review the cable modem FAQ at
> www.broadbandreports.com about DOCSIS modem performance standards. FWIW
> (and not all agree with me), upstream power less than 40dBmv is very good.
> Anything above 48-50dBmv upstream is marginal. 55dBmv is max power for a
> DOCSIS modem and on Comcast you should not see this level, according to
> the local techs. Comcast users seldom have downstream power or signal to
> noise issues.
>
> Q
I already posted my modem signals a little further up the thread. I've
read all the stuff on BBR and go there often anyway. I am about 99% sure
the problem is not at my house. My speeds have been good the last few days.
I keep a log by the way. Today for what ever reason the issue cropped up
again. This time I was ready. I had been performing Line Packet Loss
Testing from BBR while my speeds were good. Once the speeds went bad I
continued the testing and now I see a bunch of losses at my end. Now to
verify it is not my equipment I moved my cable modem and a laptop outside my
home and plugged my modem directly to the drop to my house bypassing all my
wiring, even the splitter. Upload speeds continued to be bad and Line
Packet Loss Testing from BBR still showed a problem. I called Comcast to
see what they saw on the line as well. While on hold magically my speeds
got better. While talking to the tech he did see problems on my end and my
upload speeds again went bad. I continued the BBR testing during our phone
conversation. I had number over 20% on my end. Holy cow.
Anyway I think the issue that throws most techs is that even though those
periods where my uploads speeds are crap, my downloads speeds remain
unaffected. Today the tech offered the idea that I might have a Line
Balance issue. I have another technician showing up on Friday and the issue
has been elevated. Matter of fact I was told to ask for a supervisor if not
satisfied.
One thing I have noticed that I do not like is my modem downstream power
level is varying from -6 dB to -11 dB. I have read the a variation of more
that about 2 could mean trouble. It typically averages at around -8 to -10
with day to night flucuations however I am seeing those other numbers as
well. My downstream SNR and upstream Power Levels are very consistant.
though.
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