BTW and sync speeds

[Poverty]

Does BTW, as well as the line conditions, control the sync rate?

Last autumn my sync rate had been falling slowly from around 6.3M to the low 4M with the associated download rate going from the low 5M to the low 3M.  Unfortunately this low download speed is always accompanied by the inability to watch the i-players, You-Tube or even listen to missed radio programmes due to long and frequent periods of reloading.

So I told Support and they "reset" my line.  Within a few hours the sync speed had recovered back to 6.3M and was slowly rising.  After a few weeks it attained a sync speed of around 6.8M where it stayed until a few weeks ago.  Then there was a local intermittent power failure which turned my router on and off three or four times.  After that it stayed connected at around 7M for the rest of the day, but when I switched it on the next morning it had reduced to 5.3M where it stayed for a week or more.  So I again told Support and they again reset the line.  It quickly went up to 6.3M for the next two weeks with no dropouts, but then a few mornings ago when I switched on it was down to 5.3M again where it still is.  Why is this as there had been no dropouts or reductions of sync speed at the higher speeds?  I wouldn't mind so much if these lower sync speeds didn't make watching or listening on-line impossible.

Should I again tell Support?

[Simon]

I'm no expert on the tech stuff, but I wouldn't have thought a speed of 5.3M would make audio and video streaming problematic, unless you have several connections going on at the same time.

Can you do a BT Speedtest and post the results, along with your router stats?

[Rik]

First, don't keep turning the router off, it's designed to run 24/7, and the disconnections can be taken as instability by BT's management system. I agree with Simon that the speed should not be an issue, I have a 4.2M connection, 3.5M profile and can stream without problem. I would, therefore, be looking at three issues in your case: 1) is the connection shared, as Simon says, 2) Are you connecting wirelessly, 3) Is your router showing a high error count?

[Bill]

I wouldn't mind so much if these lower sync speeds didn't make watching or listening on-line impossible.

As indicated, your speed is fine for streaming video etc, your symptoms sound more like excessive packet loss. It might be worth setting up a Broadband Quality meter to see what's going on:

http://www.thinkbroadband.com/ping

[Poverty]

Many thanks all of you.
I cannot do a BT speed test as I have a wireless router with a 100% signal strength and a 100% signal quality.
I have always switched off overnight, so why was it OK for several months achieving the 7M sync rate?
I presume that there is a lot of traffic which causes the intermittent reloading and the higher sync speeds allow it to keep up during downloading periods.
I have never had any download errors or packet losses - see the current router stats.  There are and always have been some upload errors and losses as you will see.

Device basic Info:
System MAC Address   C8:3A:35:3A:2D:08
WAN MAC Address   00:00:00:00:00:00
Firmware Version   V0.0.2_Tenda_en_100203
Wireless Version   1.20
System uptime    04:01:06s
System Time    2011-06-12 13:47:32
ADSL Information:
DSL Firmware Version    E.25.41.55 A
DSL State    Connected
Downlink rate   5344000
Uplink rate   448000
SNR (downstream)   8.0 dB
SNR (upstream)   23 dB
Line Attenuation
(downstream)   36.5 dB
Line Attenuation
(upstream)   20.0 dB
Connection Standard    G.Dmt

WAN Interface Info:
Interface    Tx packets/Errors    Rx packets/Errors
      Tx bytes/Drops            Rx bytes/Drops
LAN
(wl_filter)    53719/0              41687/0
      52218436/0           6534202/0
WAN
(Tenda)    42323/147              56712/0
      5939920/38314           51229230/0

[Simon]

I cannot do a BT speed test as I have a wireless router with a 100% signal strength and a 100% signal quality.

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

Other than the fact that it's incredibly temperamental, I don't see why you can't run a test, and it will give us your line profile, which is useful in diagnosing issues.

[pctech]

The other thing to take into account here is the AV source i.e. where the server is, if you have too much latency no matter how fast your connection is it will buffer and 5.3 Meg is more than enough to support HD video.

One of the tricks I've found works well with Youtube in particular is if you notice buffering copy the URL, close the browser, reopen it and paste the URL back in and you will find it streams smoothly.

The reason for this is that the video was probably sitting on a server in the US, when you request it Google determines you are in the UK it copies it to a UK cache so when it is requested again the server is nearer to you, thus lowering the latency (this may not work though if you are using Norton DNS or OpenDNS because the servers think you are in the States)

[Rik]

I'd also be looking for interference on the wireless channel from nearby networks.

[Poverty]

Simon
The reason thet I said that I couldn't do a BT speed test was that rule 2 says that you have to have an ethernet connection, not a wireless one.  Anyway I did the test with the following results.

Download speed achieved during the test was - 3684 Kbps
For your connection, the acceptable range of speeds is 600-7150 Kbps.
Additional Information:
Your DSL Connection Rate :5312 Kbps(DOWN-STREAM), 448 Kbps(UP-STREAM)
IP Profile for your line is - 4000 Kbps

[Simon]

That's OK, it's the IP Profile we wanted. which we've got, and it doesn't look too far out to me, but as I said, I'm no expert.

[Simon_idnet]

I'd recommend that you try streaming while your PC is connected via an ethernet cable. That would then rule out your wireless connection as a possible cause. If wired streaming works fine then you could try changing the wireless channel as it could be that a neighbour has recently started using the same wireless channel as you and so that channel is congested.

Your sync speed has dropped because the Exchange has increased your noise margin, probably due to interference (which may be from your neighbours as well).

[Poverty]

Thanks Simon.

My wireless connection is only about 3 metres as the crow flies and the router is only half a metre from the master socket (no extensions) but an ethernet cable would have to be around 25 metres long as the router is one floor below the computer.  I live in the country and my nearest neighbour is nearly 100 metres away.  The system is set for "auto detect" channel.

I have realised that BT have reduced my sync speed by increasing the noise margin, but why should they do this if there have been no download errors, dropped packets or re-syncs?  I check every evening before I switch off.  Hence my original post.  Do they take upload statistics into consideration, as this is where there have been the only errors?

[Rik]

There's been a resync between the stats in reply 4 (5334) and the BT test (5312).

[Gary]

Thats why I use the 5Ghz band it may have a shorter range but for now less interference, also check your Router some will automatically find the clearest channel depending on local interference. there are a range of tools for fining what channels your neighbours are on though just google and grab a free one.

[Simon]

Just a thought, have you recently introduced any additional electrical equipment, such as DECT phones?

[Poverty]

Rik,
Yes I know - I instigated this re-sync as someone suggested that I reduce the MTU to see if it reduced the upload errors.  I'll see what these are tonight.

[Poverty]

No, the MTU reduction made no difference.

I will give it a few more weeks and see how it goes.  I gather from a friend that it can take up to three months of good connection before the SNR margin is reduced.  But I still would like to know why it was increased in the first place.
Anyway, many thanks for all the useful tips.

[Rik]

There's only one reason target noise margin is increased, and that's to stabilise the line.

[zappaDPJ]

Just to pick up on something I've noticed in this thread; my router was set to auto detect (channel) and even though the devices connected via wireless were 2-3 meters away and picking up a full strength signal I had about 1MB/s throughput and up to 1000ms latency due to packet loss. Wired I have 32MB/s, 7ms latency and no packet loss.

I fixed the problem by simply setting a channel (currently channel 1) and my throughput went up to the almost the same speeds as my wired connection. It might be worth a try