Slow download Speeds

guppy02 · Dec 19, 2007, 17:03:49

I could help today my connection been a lot slower than usual. My download speeds usually register between 650k to 700k. However im lucky to get 300k. My speed test on thinkbroadband was 2.1mb/s

not the usually 6.5mb/s

I'm quite close to the exchange (1mile) and usually have very good reliable connection. But today has just been really bad. Any reasons why? its never been this slow before

Rik · Dec 19, 2007, 17:06:58

Can you do a BT test, and post that together with your line stats?

My guess would be you've had a low-sync event which has crippled your profile, but without stats it's just a guess.

guppy02 · Dec 19, 2007, 17:52:43

Well i have a billion router and i dont have much stats regarding the line.

This is all i can get from the router regarding the internet link

ATM connection
Port Name    a1    Active    TRUE
Rx VPI    0    Tx VPI    0
Rx VCI    38    Tx VCI    38
Rx Packets    10945    Tx Packets    7373
Rx Bad Packets    240    Tx Bad Packets    0

PPPoA Parameters
Status    open for IP, sent 7376, received 10945
LLC Headers    false
HDLC Headers    false
Authentication    chap

Rik · Dec 19, 2007, 17:53:46

How about a BT speed test? There's no information on the line in your stats, so a BT test is our best bet.

guppy02 · Dec 19, 2007, 17:56:06

you got a link?

Rik · Dec 19, 2007, 18:02:34

http://test.speedtester.bt.com:50301/

Sebby · Dec 20, 2007, 12:45:57

It certainly sounds like a profile issue. I await the results from the speed tester.

wrtpeeps · Dec 20, 2007, 17:02:29

I am also getting exceptionally slow speeds today $:-\$

Rik · Dec 20, 2007, 17:03:22

Care to quantify that?

wrtpeeps · Dec 20, 2007, 17:06:01

est1 comprises of Best Effort Test: -provides background information.
IP profile for your line is - 4500 kbps
DSL connection rate: 448 kbps(UP-STREAM) 5280 kbps(DOWN-STREAM)
Actual IP throughput achieved during the test was - 200 kbps

Rik · Dec 20, 2007, 17:08:15

You got onto the BT tester, wow!

I'm getting my normal 2400 throughput on a 2500 profile, which suggests a local congestion issue to me. It might be worth talking to support to see if they are aware of anything 'geographic' going on.

wrtpeeps · Dec 20, 2007, 17:09:49

I only just moved home this weekend, I am pretty sure it has never been this slow before.

Rik · Dec 20, 2007, 17:15:16

Has it been all day? I tend to notice some effect when schools break up. I take it you've checked whether your exchange is 'red'?

http://usertools.plus.net/exchanges/

wrtpeeps · Dec 20, 2007, 17:16:22

It's green.

Rik · Dec 20, 2007, 17:20:07

In that case, your best bet is to give support a call, 0800 0267237. They can look at what's happening in real time and, as I said, they will be able to tell you if there's a BT issue affecting you.

Sebby · Dec 20, 2007, 17:47:16

Yep, something is very wrong there, and for no apparent reason. Give support a call for sure.

guppy02 · Dec 21, 2007, 00:07:28

Ok sorry for not posting back.

The results from BT are:

Test1 comprises of Best Effort Test: -provides background information.
IP profile for your line is - 6500 kbps
DSL connection rate: 448 kbps(UP-STREAM) 8128 kbps(DOWN-STREAM)
Actual IP throughput achieved during the test was - 5499 kbps

Date 21/12/07 00:10:15
Speed Down 3434.11 Kbps ( 3.4 Mbps )
Speed Up 378.46 Kbps ( 0.4 Mbps )
Port 8095
Server speedtest1.adslguide.org.uk

However i do speedtest with thinkbroadband or speedtest.com and i get 2mb readout. The graph in my profile makes you guys look bad all of a sudden

So whats with the mixed up results?

Rik · Dec 21, 2007, 00:10:46

Speedtesters are notoriously variable, they simulate file transfers by a variety of techniques and the results will vary accordingly. On top of that, the server load at the speedtester will affect your results. The best test is to download a large file, eg a Linux distro, and time it.

Of the tests, the BT one is the best indication, and that's suggesting throughput is a bit low for your profile. You may be able to improve things by tweaking MTU & RWIN, do you know what values you are using?

Sebby · Dec 21, 2007, 00:16:37

If the BT speed tester provides those results, then it suggests an issue with the speed tester on Think Broadband and whatever other sites you've used. Everything looks fine.

Rik · Dec 21, 2007, 00:19:31

It's also worth mentioning, Guppy, that your profile is low for your sync speed, you should be seeing 7150. That suggests your line has been unstable in the past few days, and it may be that interleaving has been turned on.

guppy02 · Dec 21, 2007, 10:00:24

Quote from: Rik on Dec 21, 2007, 00:10:46
Speedtesters are notoriously variable, they simulate file transfers by a variety of techniques and the results will vary accordingly. On top of that, the server load at the speedtester will affect your results. The best test is to download a large file, eg a Linux distro, and time it.

Of the tests, the BT one is the best indication, and that's suggesting throughput is a bit low for your profile. You may be able to improve things by tweaking MTU & RWIN, do you know what values you are using?

The MTU Setting is set to 1500, I cant find an RWIN value

Rik · Dec 21, 2007, 10:05:48

Is that router and Windows? You will need something like TCP Optimizer to check the RWIN setting, see this FAQ.

Try the fragmentation test - that will determine whether you are losing any packets. Leave the router set to 1500, and only change the settings in Windows (remember to re-boot). 1458 often works well.

Sebby · Dec 21, 2007, 10:06:18

Quote from: guppy02 on Dec 21, 2007, 10:00:24
The MTU Setting is set to 1500, I cant find an RWIN value

In that case it's probably Windows' default (I believe that's 65,535, assuming you're using XP).

You might want to have a look at SpeedGuide's TCP Optimizer for an "easy" way to set the optimal RWIN value.

Rik · Dec 21, 2007, 10:08:09

Guess what I use, Sebby.

Far better than DrTCP, imo.

Sebby · Dec 21, 2007, 10:12:01

Ah, you beat me to it by exactly 30 seconds!