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Can a DSLAM (DSL Access Multiplexer) (http://www.iec.org/online/tutorials/dslam/index.html) get congested, and if it can, could it cause ping spiking?
This may sound like a strange question, but I've been emailing my ISP's network tech back n forth lately, and I'd just like to know what I'm talking about so I don't make a fool out of myself. Luckily I know enough that I could convince him that my poor DSL connection isn't because of my setup at home(they actually set it up themselves!), and has to be their fault. Now he just emails me now and then saying he made "changes" to my account and see how it works out. Even though my friend who uses the same service and only lives a mile from me has the exact same problem.
Is it possible that too many users are going through the one DSLAM and it is slowing down performance? I was reading a forum once and heard someone mention DSLAM. I just though of it for some reason so I looked it up and read all I could about it, but I'm not sure :/
omendata
08-05-2003, 10:28 PM
DSL is a dedicated line from you to the DSLam, then a trunk to 'the internet' often a T3. if the ISP has oversold the capacity of the T3, then everyone on that DSLam will slow down when it is beyond capacity so i guess the answer you are looking for is "yes" but its very rare with the bigger ISP's , more likely to happen with the cash strapped smaller ISP's.
Hmm, yeah it's a small ISP. Butler-bremer. Just a phone company for 2 counties here in Iowa. The larger NetINS used to run it out of their office, but they went independent...
So if they have oversold, which is probably likely in this case, then there probably isn't much they can do about it then?
omendata
08-05-2003, 10:58 PM
Nope.
Time to find another ISP.
sm8000
08-06-2003, 12:34 AM
Yup. Only thing they can do is add to their T3.
HumptyMoo
08-08-2003, 11:05 PM
do a "pathping 123.123.123.123" or a "tracert 123.123.123.123" of an ip address that is a long way from you (europe or problem server/website) this will then show you where your connection is letting you down....the dslam may not be overloaded (althought it does sound like your isp is to blame) it could just be a trouble some router on another backbone network.....also if the spike is due to loss, find a server that is presenting the problem and do a "ping [server ip address] -t" for 5 mins or so to show what the loss is (ctrl +c kills it)...all these commands are done through a dos prompt. Either way you should be able to pin point your slow down/spike using these tools. :(
Heres what the Internet/LAN tech said about congestion.
Our average link utilization is 30% from the DSLAM to our router. From our router out to the Internet, our average link utilization is less than 25%. It is not a bandwidth problem.
And I already know where the problem is. When my connection slows down and I run a trace route I will even get a 1000+ ping from my home to my ISP's router, a direct connection.
He told me to unhook from my home router and connect right into the modem and run a firewall for a while to see if anything is happening there, since the router has NAT enabled. I did that and didn't find anything unusual after running it for a day or two. Except I got tons of TCP (flag:s) entries on port 1214. And I don't even have any file share programs running at all, and have all spyware and other garbage cleaned, check for that daily.
The tech I talk to frequently says that this problem is "perplexing".
Anybody know of anything in between my home and their router that could be causing this? Remember it happens to my friend too who only lives a mile away from me, and about the same distance from the router.
omendata
08-09-2003, 05:51 AM
Port 1214 is Kazaa P2P - Probably just broadcasts!!!
And you really believe your ISP - tsk tsk!!!
Port 1214 is Kazaa P2P - Probably just broadcasts!!!
But I never had Kazaa running.
omendata
08-09-2003, 02:34 PM
They are port probes from other Kazaa users.
jrobbinson
08-09-2003, 06:40 PM
didn't your tech say {Our average link utilization is 30% from the DSLAM to our router. From our router out to the Internet} the only thing between your modem and the router is the DSLAM.
but according to the ping the problem is the router.
So it goes NIC - Cable - Modem - Phone Line - DSLAM - Router - Internet?
And since I already know it's not the NIC, Cable, or Modem since the EXACT same thing happens at my friends house about a mile away, and everything is hooked up correctly, it has to be the Phone Line, DSLAM, or router.
Is there a certain setting that he could have set wrong to make it so the ping will spike a lot.. since I get 1000+ ping spikes to their router a lot. I remember taking a class through Cisco in college where we had to log into routers and learn all these commands and what not. Don't remember much about it, but I know there were lots of differant settings.
I'll ask him if their router is messed up.
Oh, is it possible that the phone line is screwed up some how, or wouldn't that have anything to do with it?
omendata
08-11-2003, 09:06 PM
Nope.
Time to find another ISP.
They can't just replace their router? I'll ask him.
sm8000
08-12-2003, 03:37 AM
I doubt they will, based on the feedback of one customer who, for all they know, could simply be reading off a screen like their first level tech support. :(
If you can afford it, look into satellite.
It's not just me, everybody that lives in my town has the same problem, most people are just casual users and don't even know about it though. And it is a pretty small ISP where you actually get to talk to the head guy on a regular basis on the phone, or through email like I have been doing daily. He is actually from the same town, population 1400, so it's hard not to know people around here.
Plus there isn't any other ISP other than through Mediacom cable. And the price for that is crazy if you don't get your cable TV through them. Plus I know a couple people who have that and it may have faster speeds, but over all it isn't as reliable.
omendata
08-12-2003, 06:23 PM
Everybody in your town - wow - 1400 unsatisfied users and you know em all - im impressed
:D
You will just have to put up with substandard service and dumbass technicians who'd rather while away their time smoking 20 regal and playing network Doom than fixing a problem.
The wee man has no power these days.
Why not start a protest website or seeing as you are a Yank , why not pop down to the ISP , Uzi submachine gun in one hand , rocket launcher in the other and demand satisfaction (after all the customer is always right) - I believe its quite a common method of persuasion in the States!!!
:(:D :t
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