DSL - slowdowns?

English Open Chat
1

Well, first off. This may be only for the USA.

I have AT&T DSL Elite and i noticed that my connections drops a couple of times.
My connections is wired based and use a cheap Linksys router on which i hooked up my PC and my Xbox.

Sometimes the connection drops on the PC in which all services stop working for a minute or so. Not a big deal.
But i also notice that if i watch Netflix that my connections slows down.
Now with all the net neutrality i am kinda curious if AT&T maybe slows my connection down for streaming. Or if simply Netflix sucks.
Theoretically, i could ping the connections, but since i don’t know which ip the service for stream is i am somewhat lost.
I like to isolate the problem to fix it.

Did any other user here (with AT&T) had or has the same problem and how did you fix it?

2

On Wed, 05 Jan 2011 01:06:01 +0000, yester64 wrote:

> Well, first off. This may be only for the USA.
>
> I have AT&T DSL Elite and i noticed that my connections drops a couple
> of times.
> My connections is wired based and use a cheap Linksys router on which i
> hooked up my PC and my Xbox.
>
> Sometimes the connection drops on the PC in which all services stop
> working for a minute or so. Not a big deal. But i also notice that if i
> watch Netflix that my connections slows down.
> Now with all the net neutrality i am kinda curious if AT&T maybe slows
> my connection down for streaming. Or if simply Netflix sucks.
> Theoretically, i could ping the connections, but since i don’t know
> which ip the service for stream is i am somewhat lost. I like to isolate
> the problem to fix it.
>
> Did any other user here (with AT&T) had or has the same problem and how
> did you fix it?

I don’t use AT&T, but I do stream Netflix to my PS3 here at home.
Generally, it’s OK, but occasionally I do have problems with not
buffering enough data.

I don’t think what you’re seeing has to do with the new net neutrality
rules - they’re so recent, I doubt any ISP has had a chance to implement
anything that they’re not already using.

If you note the DSL connection dropping, though, you might try (depending
on the router you’re using) seeing if there’s a way to increase the
number of dropped DSL ping attempts made before the connection is dropped
and re-established. When I replaced my Belkin router with a D-Link
router with OpenWRT on it, I found that the connection drops were about
every 5 minutes (and it was worse when the bandwidth was more utilized)
at the worst point, and tweaking that setting helped tremendously.

Jim

Jim Henderson
openSUSE Forums Administrator
Forum Use Terms & Conditions at http://tinyurl.com/openSUSE-T-C

3

I’ve got to investigate that :slight_smile:
But its true. I really suspected that my dsl provider might slow down my connection.
Maybe thats just a little paranoid.

I will see about the router. Its a cheap one, nothing special, but perhaps that will solve the problem to a degree.

But i wonder if that is causing also the slow down. Mm… will see.

4

On Wed, 05 Jan 2011 03:36:02 +0000, yester64 wrote:

> I’ve got to investigate that :slight_smile:
> But its true. I really suspected that my dsl provider might slow down my
> connection.
> Maybe thats just a little paranoid.
>
> I will see about the router. Its a cheap one, nothing special, but
> perhaps that will solve the problem to a degree.
>
> But i wonder if that is causing also the slow down. Mm… will see.

Another thought that came to mind is that maybe Netflix is doing
something like Apple is with iTunes - if you’re using something like
Google’s DNS, there were reports a few days ago that the iTunes servers
were doing geolocation based on the DNS server, and if you’re not using
your ISP’s DNS server, then the geolocation is pointing to a server
that’s farther away from you than you might want.

I thought it was perhaps a bogus problem, but people started doing tests
and actually found that there were significant differences in download
times from iTunes.

The reason I thought it might be a bogus issue is because the proper way
to do geolocation (in my view) is to look at the requesting IP address’
location rather than the DNS server’s location (for that very reason).
But it seems that some of the “smart” DNS servers might actually be
serving up different DNS resolutions based on the DNS server’s location
instead (which IMHO is a less efficient way to do this since you’re not
trying to get data to the DNS server, but to the client requesting the
data).

But if you use something other than your ISP’s DNS server, that might be
something to check out.

Jim

–
Jim Henderson
openSUSE Forums Administrator
Forum Use Terms & Conditions at http://tinyurl.com/openSUSE-T-C

5

Even a cheap router is usually much more than enough for home use (unless You’ve got some site-to-site vpns) so I wouldn’t suspect that’s the problem.

Best regards,
Greg

6

On 2011-01-06 06:59, Jim Henderson wrote:

> Another thought that came to mind is that maybe Netflix is doing
> something like Apple is with iTunes - if you’re using something like
> Google’s DNS, there were reports a few days ago that the iTunes servers
> were doing geolocation based on the DNS server, and if you’re not using
> your ISP’s DNS server, then the geolocation is pointing to a server
> that’s farther away from you than you might want.

I’m curious: how can they learn what DNS server you use?

> The reason I thought it might be a bogus issue is because the proper way
> to do geolocation (in my view) is to look at the requesting IP address’
> location rather than the DNS server’s location (for that very reason).

Indeed!

> But it seems that some of the “smart” DNS servers might actually be
> serving up different DNS resolutions based on the DNS server’s location
> instead (which IMHO is a less efficient way to do this since you’re not
> trying to get data to the DNS server, but to the client requesting the
> data).

I think I understand.

If you use DNS server A, and we make the assumption that you are, network-wise, close to it, and
that DNS server gives you the IP addresses of download servers also close to you, speed is good. Why
don’t calculate a good server based on your IP instead? Because that calculation has to be done
somewhere, probably by the main server. This way, they don’t make any calculation at all, the DNS
server gives you the correct servers without calculations, simply giving you the data it has. DNS
server B will have a different table.

They are not using geolocation, but ISP location. With this scheme, they may have download servers
located in the infraestructure of each ISP, so that they do not have to use the highway, for which
they have to pay.

Just a guess.

–
Cheers / Saludos,

Carlos E. R.
(from 11.2 x86_64 “Emerald” GM (Minas Tirith))

7

Yes, I have ATT and sometimes the connections are slower than expected. Sometimes I can clear it up by restarting the browser but some days connects to some sites are slow.

Not sure which service level I have but I watch Netflix over both wired or wireless through a cheaper router and after a few minutes the movies usually settle into smooth video frame rates. Even at full screen, though sometime YouTube videos slow down when played at full screen.

Make sure you cancel or minimize other apps, browser tabs, etc. BTW, how are you watching Netflix from Linux? I didn’t know that’s possible. some kind of OS block. I have to use Windows to watch Netflix.

8

I have to tell you, that i forgot to mention it.
I don’t use the computer at all. It goes via Xbox on my TV screen but using the router which shares the line between the computer and the xbox.

9

On Sat, 08 Jan 2011 21:30:27 +0000, Carlos E. R. wrote:

> On 2011-01-06 06:59, Jim Henderson wrote:
>
>> Another thought that came to mind is that maybe Netflix is doing
>> something like Apple is with iTunes - if you’re using something like
>> Google’s DNS, there were reports a few days ago that the iTunes servers
>> were doing geolocation based on the DNS server, and if you’re not using
>> your ISP’s DNS server, then the geolocation is pointing to a server
>> that’s farther away from you than you might want.
>
> I’m curious: how can they learn what DNS server you use?

That was what made me think it was a bogus idea, but I suppose what they
could do is distribute the IP addresses for a DNS to the DNS server based
on the geographic location of the DNS server. Then it doesn’t matter -
it’s a question of what information they pass to the DNS server when the
resolution request takes place (ie, the DNS server’s recursion).

>> But it seems that some of the “smart” DNS servers might actually be
>> serving up different DNS resolutions based on the DNS server’s location
>> instead (which IMHO is a less efficient way to do this since you’re not
>> trying to get data to the DNS server, but to the client requesting the
>> data).
>
> I think I understand.
>
> If you use DNS server A, and we make the assumption that you are,
> network-wise, close to it, and that DNS server gives you the IP
> addresses of download servers also close to you, speed is good. Why
> don’t calculate a good server based on your IP instead? Because that
> calculation has to be done somewhere, probably by the main server. This
> way, they don’t make any calculation at all, the DNS server gives you
> the correct servers without calculations, simply giving you the data it
> has. DNS server B will have a different table.

Yep. That’s what I think.

> They are not using geolocation, but ISP location. With this scheme, they
> may have download servers located in the infraestructure of each ISP, so
> that they do not have to use the highway, for which they have to pay.

Essentially that would be correct. Remember that DNS is based on
recursive requests - so if your ISP’s DNS server doesn’t have the
address, it asks upstream, and the upstream server can make a decision
what address to serve based on where the requesting DNS server is located.

> Just a guess.

Same here. But I think it’s a logical one.

Jim

–
Jim Henderson
openSUSE Forums Administrator
Forum Use Terms & Conditions at http://tinyurl.com/openSUSE-T-C

10

I got to check this with my router, which is netgear (i was wrong).
But i can not find anything in the setting regarding ping. Is there another term for it? I got to check on netgear.

11

It might be called system test on a router tool page. That’s where mine is.

12

Its called MTU (Maximum Transmission Unit) on Netgear. Default is 1500, i changed it to 1400 and see what happens.

13

Ping on router is not the same as MTU. Changing the MTU to a smaller size sometimes helps transmission.

I used it a long time ago when connections took a long time to connect to specific sites. But it worked best with ping subtracting 28-30bytes to determine the best size:

ping Central Ohio News, Sports, Arts & Classifieds | The Columbus Dispatch -f -l 1472

You could set MTU 1472 see if that improves performance, then set it lower, etc
Max MTU: How do I find mine? Tweaking FAQ | DSLReports.com, ISP Information
How do I find my optimum MTU setting? AT&T Southeast Forum FAQ | DSLReports.com, ISP Information

14

After i wrote it, it occurred to me that it is not the same.
But it may help. Still have to fiddle a little.

The ping is another mystery i can not get my head around. I just don’t find anything to it in my settings.
But i noticed that i don’t look in with my router onto my network. Not sure if that makes a difference.

15

Not a problem.

When I get into my router I have a number of screens available to me. Status, Setup, Tools, Advanced. Each of those have a few screens.
One of those screens allows me to System Test which is basically a ping outward on the Wan (Yahoo!) or inward to the Lan (192.168.0.2).

16

I work for an ISP, and I deal with this a lot.
From having worked for a DSL ISP before, it could be the DSLAM or noise on the line. You’re SNR might be tanked. Call to have it checked.
Another thing I have noticed working for the current ISP which is a cable provider, is that when I have my customers run tracert (in windows) or traceroute (in Linux even though we don’t support Linux) to netflix, after a few hops it often starts going through AT&T servers which have times in milliseconds of well over 100 ms. Running traceroute might shed some light on it.

If you have AT&T DSL you probably have a 2Wire modem. Start a thread and post me the logs of the modem. I used to decipher them all the time. By the way, as a point of interest, the 2wire modems are written in python.