Slow down

Morning all

has anyone else noticed a slow down , gone from roughly 33meg to 24meg over the past 3 days.

BT Infinity are my provider.

Mine went up 3 days ago, from 14 to 16.8 , quite spooky to say its 3 lots of wet string between the cab and me

Would this beta test result be consistant with fairly descent line stats ?



1. Best Effort Test: -provides background information.

Download Speed
35512 Kbps

0 Kbps 38715 Kbps
Max Achievable Speed

> Download speedachieved during the test was - 35512 Kbps
For your connection, the acceptable range of speedsis 12000-38715 Kbps .
Additional Information:
IP Profile for your line is -38715 Kbps

2. Upstream Test: -provides background information.

Upload Speed
8139 Kbps

0 Kbps 10000 Kbps
Max Achievable Speed

>Upload speed achieved during the test was - 8139 Kbps
Additional Information:
Upstream Rate IP profile on your line is - 10000 Kbps

In reply to a post by KayCee:

Would this beta test result be consistant with fairly descent line stats ?

That's not the beta test. That's the full one .

It shows you are less than 700 metres from the cabinet, and that your ISP is providing a decent throughput.

Hi RobertoS,

In reply to a post by RobertoS:

It shows you are less than 700 metres from the cabinet, and that your ISP is providing a decent throughput.

From the 38715 K IP Profile, we can determine the sync speed is 39999 K (IP Profile = 96.79% of sync speed).

Throughput looks little low though as throughput (at quiet times) is usually around 97% of IP Profile, which would equate to approximately 37500 K.


How have you determined the distance from the cabinet as less than 700m?
i.e do you have a chart, or a formula for typical speed v distance?

I have been trying to track down & even compile my own chart for speed v distance without much success.
I appreciate it could only ever be approximate & would be very much dependent upon the physical characteristics of the D-side cabling, but a "typical" speed v distance chart would be most useful.

THe only charts I have managed to locate so far do not actually start off at 40Mb.

Paul.

EDIT:
35512 K looks a little like the Plusnet throughput where their own "Current Line Speed" is occasionally a little out of kilter with BT's IP Profiles.

Edited by deleted (Thu 02-Feb-12 23:01:18)

In reply to a post by Bald_Eagle1:

From the 38715 K IP Profile, we can determine the sync speed is 39999 K (IP Profile = 96.79% of sync speed).

Agreed.

Throughput looks little low though as throughput (at quiet times) is usually around 97% of IP Profile, which would equate to approximately 37500 K.

I think you are thinking of Infinity? I haven't seen over 36500kbps on tbb, similar better on BT, slightly better as expected on speedtest.net. I usually run wirelessly, but those top figures are wired. I'm aiming to do a few wired ones, tbb and BT, over the next few days.

How have you determined the distance from the cabinet as less than 700m?

A guess from my own line where I know the D-side is excellent, at 600 metres, attenuation 17.3dB, SNRM 7.3dB on engineer installation test, and a couple of other 600 metre profile posts by others. Also Zarjaz has posted a few lines the length of lines he has connected that achieved 40Mbps, but they've just sunk into my subconscious. Maybe you could ask him?

do you have a chart, or a formula for typical speed v distance?

Nope, sorry. I posted about this a few days ago and got a couple of helpful replies, but not had chance to follow it up. Forgot, if the truth be told .

In reply to a post by RobertoS:

In reply to a post by Bald_Eagle1:

Throughput looks little low though as throughput (at quiet times) is usually around 97% of IP Profile, which would equate to approximately 37500 K.

I think you are thinking of Infinity? I haven't seen over 36500kbps on tbb, similar better on BT, slightly better as expected on speedtest.net.

Speedtest.net will give me 37.5Mbps when I have a "fast" PPP session, and 35 Mbps when I have a "slow" one (sync always 39999).

BT's speedtester is rather more variable, and usually comes out to be 2-3Mbps below this figure - so 32-33 when "slow" and 34-35 when "fast". It is hard to retry this one easily because of the 1 hour limit.

Edited by deleted (Fri 03-Feb-12 01:07:40)

Do you mean short or for long periods?

Ive been reporting routing and slow speeds for months, now getting the reply use BT checker wich has time limits between being able to use.
Clicky

@WWWombat,

In reply to a post by WWWombat:

BT's speedtester is rather more variable, and usually comes out to be 2-3Mbps below this figure - so 32-33 when "slow" and 34-35 when "fast". It is hard to retry this one easily because of the 1 hour limit.

It was actually some of your & other members previous posts in the Plusnet forum that I was thinking of when I mentioned the 37.5Mb.

I had forgotten about the BT speed test always being 2Mb or so more pessimistic than speedtest.net on my own connection - I have even posted mentioning that alsewhere - Doh!!!


@ RobertoS,

Zarjaz has previously mentioned he has seen the full 40Mb on a 1000m line (maybe that was an exceptionally good D-side), but also as low as 16Mb on a 1000m line (maybe that one included a substantial amount of aluminium cabling).

Paul.

Thank you for the reponse and analysis.

When I have tried a Newsgroup download I get the correct throughput of around 4.5mb per second , but if I use the Speedtester.net site I get :

http://www.speedtest.net/result/1748814578.png

Its not a big deal and the speed I get is more than usable , just something I have noticed in the last 4 or 5 days.

Like anything else, the speed test systems are subject to congestion, routing/peering and loading issues; I guess that's why the main BT test site limits retests to take place after an hour, and even then it's not great. http://speed.io is an alternative but still subject to the same kind of limitations, and the BT beta test for >40 Mbit/s often seems to be able to drive things flat-out (but perhaps not for much longer ).

Some services - like the news feed you mention - often seem to have more capacity than the testing services; e.g., I've seen iTunes run flat-out at 4.6 MB/s for >10 mins at a time. This is hardly surprising given the job they're intended for, whereas most speed test systems seem to be a "best efforts" affair.

Also, don't always rely on the result given by by the testers as they may average rise/fall and drop-outs. Use network monitoring tools(*) where available to monitor "instantaneous" (really short-term averages, e.g., 1s) rates and average over the flat-out values, since peaks may be higher due to buffering.

Although it's not so useful for bandwidth checks, Netalyzr at UC Berkeley is useful for a general health check and spotting - if not fixing - buffering and latency issues in your ISP's network (wired ethernet please, unless you want to see the consequences of running wireless).

* I think TBB have something for Windows; there's Activity Monitor on Mac OS X and there are various things for *N*X systems, e.g., bwm-ng, ntop etc.

Edited by deleted (Fri 03-Feb-12 11:43:08)