What is causing my DSL slowdown?
September 14, 2008 6:30 PM   Subscribe

What is causing my DSL slowdown?

Ok...suddenly my home DSL connection became very unstable. I'm working on a very stable and relatively static computer setup at home. My main box is a Kubuntu 7.10 distro running on a Core2 box. My router is a Belkin Vision N1. Everything was working great until I called up AT&T (my DSL provider) and upgraded my service from 3MB to 6MB (and saved myself $5/mo in the process....go figure).

anyway about that time i noticed that pageviews seemed to take a LOT longer....sometimes 10+ seconds to bring up a website. quite often my browser will timeout waiting for a page to load. watching the handy speedometer on the router indicates very long periods of inactivity. when it *does* connect it truly does reflect the new speed of my connection (typically 4.5MB...which is pretty much what i expected). also my usenet newsreader has been reporting errors with literally everything it downloads. no idea why.

everything in this setup was working well for a long time *before* the upgrade. the only new factor is the call to AT&T that triggered some type of activity on my connection. i suspect i got switched to a different server or set of trunk lines or something and that new topology is buggy. how can i diagnose it further? are there any tools that can robustly test my setup/connection and expose a likely culprit in the path between me and the rest of the world? my calls to AT&T have resulted in nothing but "we tested your line and it appears to be fine."

and i feel i need to give a bit more information: yes i've rebooted/cycled everything in the setups. i've even replaced the router with an old Linksys i had sitting around to no avail. every machine in the house (2 linux machines, 1 windows box, 1 windows laptop and 2 macbook pros) experiences the symptoms and it doesn't matter if they are wireless, wired, connected to the router or going through a secondary switch.

thanks for any help
posted by monkeybutt to Computers & Internet (8 answers total) 2 users marked this as a favorite
"when it *does* connect it truly does reflect the new speed of my connection"

You're suffering from crappy DNS servers at your ISP. It's a common problem. Some people like to try switching to OpenDNS, but I like just using,,, and when problems arise.
posted by majick at 6:39 PM on September 14, 2008

Everything was working great until I called up AT&T (my DSL provider) and upgraded my service from 3MB to 6MB (and saved myself $5/mo in the process....go figure).

The problem is that your line is not rated for 6mbps, so what is happening at sync time is your DSL modem is freaking out trying to sync at 6mbps. You need to call your provider and tell them your issue, most likely they will just put you back on your old plan.

This happened to me a while ago when I tried to move up to a faster plan but Im so far from the CO that my signal/noise ratio didnt support the new speed. I suspect this is happening to you. I'm sure the engineers there know you cant support this speed, but AT&T wouldnt mind selling you the higher priced package and I dont believe they warn their sales CSR about this kind of thing. If it doesnt work then its the technical support team handles the problem.
posted by damn dirty ape at 8:36 PM on September 14, 2008

I don't get the DNS diagnosis. I'm with damn dirty ape, it sound like they've pushed you into a speed grade that the infrastructure can't support.

What kind of DSL modem do you have? You might be able to get a diagnostic page that shows whether it is retraining a lot.
posted by Good Brain at 9:02 PM on September 14, 2008

We are having the same problem with at&t dsl \right now. Called 611 today but they were too understaffed to handle the call. sigh.
posted by bottlebrushtree at 9:57 PM on September 14, 2008

thanks for all the suggestions. they actually all sound resonable. the DNS hypothesis makes sense b/c when i browse to a website i get incredibly long waits as the status bar in my browser says "looking up XXXXX" and every site affiliated with that site (things like ads.doubleclick.net, etc) get their own wait for "looking up XXXXX"....so *that* makes sense.

if i mange to get escalated to a higher tier of support (something *not* in india) i might be able to grill them on the infrastructure issue...now that i know about it i can speak somewhat intelligently.

as a sidenote: the pricing for the faster class of DSL was actually $5 cheaper....i had called up to look into bundling my services because i saw promos for that type of thing (phone/internet/tv/mobile). unfortunately since i was already a customer of the satellite they partner with i was inelligible for the deal, but the nice girl on the phone reviewed my account and said i could upgrade AND save some money....i guess the DSL i was on prior had been a sweet deal 4 years ago when i signed up for it but now it has been replaced by better offers.

bottlebrushtree: if you happen to get some satisfaction from AT&T i'd love to know about it.

thanks all
posted by monkeybutt at 10:22 PM on September 14, 2008

Damn Dirty Ape has it; the person who reviewed your account doesn't understand the technical limitations, and the person flipping the switch on the bandwidth perhaps didn't feel like running a line check first, perhaps feeling that if it became a problem you'd call customer service.

I know this because my ISP (not a big boxer like AT&T) actively tried to discourage me from ramping up my speed, even though it would have gotten them more money; from their perspective, it would make my service lousy and they might lose me as a customer. I didn't believe them, and asked in writing to give it a shot for a week despite what the line reading said, because I planned to upgrade for the additional static IPs (the speed was just a nice bonus, if it worked.) It didn't, and the problems were just like you describe. Calling them with a mea culpa and having them ramp the speed back down fixed things.
posted by davejay at 1:17 AM on September 15, 2008

Hang in there- I was in the exact same situation a month ago (AT&T Elite upgrade gone bad).

First, I had to spend a couple miserable hours on the phone. The 1st tier customer service technicians tend to be rude and barely understandable. The trick is if you don't like the person you're dealing with, hang up and try again. Eventually, I got a 1st tier who acknowledged that the problem wasn't with my computer or with metal halide streetlights outside my house (seriously).

I was given a second tier phone number, and the service rep tried some more sophisticated tests and still couldn't get the correct speed. We had to schedule a service call to my house. When the service tech arrived the next day, it only took him 5 minutes to fix everything. Apparently all the wiring in my house was split from a single source. He isolated the phone line that went to my DSL modem and everything works great now.
posted by tfmm at 9:40 AM on September 15, 2008

The easiest think you can do that might get you a better connection is to "reset the stack"

good Instructions for vista are at:Windows Vista - How to Reset the TCP/IP Stack
posted by phllip.phillip at 10:58 PM on September 15, 2008

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