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ADSL operation question...

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GhostRider2110

Technical User
Feb 13, 2003
7
US
Background: Starting about 2 weeks ago, my throughput over my ADSL line has dropped by 300+kbs... But is not a constant, at times I can get good 590+ but then at other times I am getting as low as 56kb (yes modem v.90 speed). My provider claims it is the distance from the DSLAM, but I have had the service for over a year and this is just started. I can see distance from DSLAM caused my overall throughput to be limited, but to me that would be a constant and would place a cap on my max. I will be humming along as 500+ and suddenly drop down to 190-200 and then even down lower.. then up to 400-500 then back down. My question.. Is my provider telling me the truth? Is my distance from the DSLAM to blame for this? If so, why would it just show up now.. about a year of service. Thanks for any help....
 
The distance could be a factor, but I doubt if it's the whole story. Monitor this behavior for some time to see if there's any pattern. For example does it happen consistantly between 4:00 - 6:00 PM when everyone nearby gets home and starts making phone calls & surfing the internet? Are there any telephones in use on your line when it happens? Maybe your ISP has added some heavy users in your immediate area.
 
Oh, 1 more thing that you've probably checked alread, but I should mention it...Make sure there's nothing going on with your PC that would cause reduced apparent bandwidth - like background downloading of virus definitions, a trojan doing something devious, or any app that could possibly be getting something from the internet without being obvious - even Quicken does this.
 
Thanks smah... No nothing is going on.. and I have check it from different computers in the house.. both through and bypassing the firewall router... The last check I did was this morning about 5:30am and I was down to a rate of 65kb... I make the checks to differnt sites.. My ISP (who is different from my DSL service provider), DSL reports speed test and pcpitstop.. all seem to be within 10% of each other... The really strange thing is.. when my DL speed is below 100Kb.. my upload speed is still 120kb... steady.. Thanks
 
It sounds like someone is hogging the available down bandwidth. It might be worthwile to use some of the other tools at DSL reports. Line Monitor, Line Quality and Dr. Ping might provide some clues.
 
I've had a similar issue before. I don't think your distance from your DSLAM is the issue. Like you said, you had this service for a year and never had this issue before. It's not likely your provider will change your distance for no apparent reason.

Try a continuous ping to a website. See what kind of ping times you get. Also pay attention to any packet loss. This is more likely. In actuality, your issue may be packet loss which results in your PC needing to re-request the info again and again. The end result will be slower performance.

If you do see packet loss then try tracerouting to see where the packet apparently gets lost. You may have to do this several times to catch the packet loss. In any case the problem could be downstream from your provider's DSLAM. Maybe they need to rebuild a PVC somewhere to clear the packet loss.
 
I would expect that the problems you see is conncted to what other users on your providors network is doing.

Most ISP's / DSL providors in my part of the world use overbooking on the backbone and what you will see is that your download rates drop, but since most people download you will not see it on the upload speed.
Using ping to test will most likely not show anything because ping doesn't get hit very hard of limited bandwith.

You need to find a server to download from that you know doesn't have problems including it's access to bandwith. Make sure that (seen from the network) that it is near you and test downloads from it on a specific time intervals.

But you will most likely not get any thing out of it because event if you can see that you providor is "over booking" his backbone how will you get him to change this.
You can't expect to get "Leased line service" paying for and ADSL line.
 
I'm in training for SBC Yahoo! Dsl support, and the first thing that we suspect (and the only thing that i've learned so far) is a TON of things can interfere with your DSL, a dusk to dawn light, or anything of the sort, especially if you notice it during certian hours, um AM Radio's are the biggest disturber. . on time an AM Radio station got built next door to a dsl subscriber, and it killed thier connection totally. I'd just look around outside or around your modem lines when you are experiencing bandwidth drop offs, especially during a consistent timed intervals.
 
Update.... Well nothing has really changed.. The phone company told my ISP they were going to be looking at the "mappings".. Not really sure what that means.... No new AM stations around in the area and did a quick check and no stations in the area have have change signal strength... No D-D lights.. Nothing on my end changed.. I'm checking the thruput as often as I can at as various times of the day as possible... There does not seem to be a pattern... Bright spot... they are still looking at it... Will keep all posted.. Thanks for the input...
 
Have the ISP do a line test, unplug all the phones on the line, move your cell phone away from your DSL modem or lines, remove any filters or line protectors you have your phone or DSL lines going trough. It could be a connection problem on a pole, terminal, your house, even your NIC could be the culprit... These types of intermittant problems are the hardest to track down..
Keep trying your ISP, I had a simmilar problem in that they replaced a old cable with a new one to our subdivision and my bandwidth droped abruply,,, come to find out they had routed me aroudn the block first.. I was already at max distance from CO... they fixed it and has been stable sence..Took about 30 trouble reports and a threat to discontinue service .. OK !
 
This is great info guys.... Let everything that have breath praise the Lord.
 
Update...
Verizon eng did more tracing and found that a T1 had been added to the "binder" I was on.. That should not have happened... They moved the T1 and things are better. I am still getting some drop in speed at time (I may just be more sensitive to speed drops now than before)... But currently things are better. and from verizion the best they will get. Thanks for all the advise.. Much of which I had already tried before calling them the first time... Great stuff!!!

 
My experience with phone companys, manily pacbell now sbc, is they overbook very often (all the time?) and the squeaky wheel gets the bandwidth. Some times it takes a lot of squeaking. After you've been quiet for awhile, some other customer's squeaks call for a boost and then watch out, it might be yours that gets rerouted.
 
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