Virgin ADSL - Possibly being capped?

For about a year my TP-Link TD-W8980 router has been showing a sync speed of 3750kbps, a SNR of 12db and a Line Attenuation of 54db. I live 3.5Km (line length) from the exchange.

Our actually throughput maxed out at 1.20mbps

After a phone line failure and some trouble with the broadband we opened up a fault with Virgin and eventually got a BT engineer out to test our line. While doing his tests i was able to see that he was also getting a sync speed of 3750kbps.

Realising that this was a consistent speed I tested a friends BT Broadband who lives about 1km further down the same line (confirmed by BT engineer) as I do. He was able to get a throughput speed of 2.60mbps!

From this I then used the BT Wholesale test website (www.speedtest.btwholesale.com) to see if there where any problems there. From that I could clearly see that the sync speed was at 3750kbps but the IP Profile that was on our line was 1.25mbps!

For the year previous I had seen this sync speed on my router but was oblivious to it, and we believed that 1.20mbps was all our line could support but after 2 weeks of reading hundreds of documents and information on how exchanges actually function, seeing these test readings from both my router and the BT engineer and being on the phone with the Virgin First Level Fault team I now think that what we are getting is just not acceptable.

So:

Type: ADSLmax
Sync Speed: 3750kbps
SNR: 12db
Line Attenuation: 54db
Line Length: 3.5KM
Phone Line: From exchange to my house upgraded within the year 2013
(Confirmed by BT Engineer)
IP Profile: 1.25mbps

I have had the line reset by Virgin with no positive results. So either Virgin are limiting my connection to the exchange or the exchange is being banded/capped to not allow us to increase our IP Profile and therefore our speed.

Any more help on this would be greatly appreciated. Thanks.

Probably the old IPStream Max service where it takes up to five days for the IP Profile to recover from a low value to the current level that is to be expected from the connection speed.

The ISP cannot limit the IP profile, it is either stuck or the modem has connected at that sort of slow speed at some point in the last five days.

Thanks for that, I haven't seen much about IP Profile capping so couldn't be sure.

Would it be possible however for the ISP to Cap the sync speed to the exchange?

From I got the line reset the sync is now maxing out at 2880kbps. (Current Rate: 2528kbps) which to me is very suspicious since the Virgin team where constantly trying to assure me the line range was between 0.70 - 2.50 mbps. I can no longer sync at 3750kbps.

I have purchased a Billion 7800N Modem/Router based on quite a few reviews saying how stable it is and how its improved their low connection speeds.
What change over procedure should i go through to get the best reset at the exchange side?
I was considering leaving the old router off for a day or so then hooking up the new router and waiting about a week to see if the IP Profile increases. Would there be much benefit from this?

Thanks again.

Just to add to that previous post, when I had my line reset I went through the 5+ day training period that Virgin advised me of. Unfortunately they did not mention that resetting the modem/router would cause the exchange to see it as a sync fault and in turn lower my connection.

I did however (after a lot more reading) leave the modem/router running for 4+ days with no evidence that anything was improving

IPStream Max has a 10 day window when it learns a figure that does nothing other than feed back into the checkers.

In short Virgin are making it all up.

Resetting the modem should only cause the DLM to kick in if done more than around 10 times in an hour.

On IP Profile read
http://www.thinkbroadband.com/faq/sections/radsl.htm...
and
http://www.thinkbroadband.com/faq/sections/radsl.htm...

More helpful information thanks for that.

Is it possible for the sync speed to be capped? Its very odd after a year of 3750kbps going down to 2500kbps after complaining about speeds.

EDIT:
The sync speed has just dropped to 1720kbps and the speed checker at (http://www.coolwebhome.co.uk/calc/index.php) is now saying this is a bad connection.
Should the sync speed be continually dropping like this?

Edited by deleted (Tue 04-Mar-14 19:18:31)

The target noise margin controls sync speed what are the full set of stats from the modem

The SNR Margin on the downstream is currently (22:49) at 9.5db but 90% of the time this is at 13db.

There has been no change in sync speed since earlier today when it dropped to 1920kbps.

I asked the BT engineer about this and he said we should be fine between 9 to 15db for getting speeds of 3.5mb. We where of course getting a sync speed of 3750kbps at the time.

Edited by deleted (Tue 04-Mar-14 22:52:37)

Okay a SNR margin changing between 9dB and 13dB while remaining connected points to a noise problem that may be in the BT network or may be in your home.

Have you tested the exact set of router stats at the test socket (because of the IP profile) speeds will not improve for some days, but the set of figures will be useful and if better suggest it is some extension wiring picking up noise in the home.

We had the BT engineer install a new master socket with the adsl filter built in so the broadband signal is stopped before it reaches any other extensions (which where also tested and found to be ok).

The router is in my hall on a table with nothing else in the hall what so ever. The nearest thing to it or the line would be a TV around 10ft away and behind a brick wall. This also includes central heating, the router is probably furthest away from any pipes or pumps that it could possibly be, in the whole house.

The BT engineer tested the line and looked for tree rub and said he didn't find anything to suggest we would have any problems.

It would be good if there where more tests that could possibly be done to maybe narrow down this problem.

Edited by deleted (Tue 04-Mar-14 23:50:06)

A case now of monitoring the router stats and keeping a record of how they change over time.

BTW radio interference can travel many miles, and probably find the SNR margin is worse once the sun has set

The SNR Margin is now up at 18.7db, thats quite a dramatic change from last night and from the usual 13db.

The new modem/router should be here today so ill get that hooked up and see how it goes for the next few days.

Probably because the night time noise has now gone (due to ionosphere) and the modem will only recover the spare margin and pick up the speed if you reboot it, i.e. turn off count to ten and turn on again

So I got the new router and its been a bitter sweet experience.

Within an hour of the new router being installed the sync rate went right up to 2800kbps, as the old router did every time it was rebooted, but unlike the old router, which quickly fell back down to 1700kbps, the new router stayed at 2800kbps.

This then must have kicked the exchange into rising my IP profile right up to 2.5mbps! So for a couple of hours my download speed held strong (no drop outs or messing about) at 2.34mbps. This is what I have been fighting for, granted a small increase from 1.2mbps but this is double what I have been getting so I will take every last drop and be overjoyed all the same.

But before this glorious new bandwidth could be enjoyed out of nowhere the sync rate dropped right down to 1780kbps and so the download rate went with it, even though for about an hour afterwards the IP profile was still showing 2.5mbps.

Eventually it too dropped right down to 1.25mbps (even though with my sync rate it should be 1.5mbps).

So here I am, back where I started with only a taste of what I can actually achieve but can't seem to hold on to.

My plan is to wait for 14 days and hope that the exchange can come to senses and not only raise my IP profile but with a noise margin of 18db, hopefully come to realise that I can actually receive 2.5mbps.

If you have any ideas on what may have happened here I would love to know your thoughts. Cheers.

At a guess the sun set, and the amount of noise picked up from AM radio stations increased, caused the modem to resync, or was a transient noise burst e.g. heating pump or turning on a CFL light build and that noise has now gone away and the noise margin has improved.

If the sync rate is low, but noise margin high then the modem will sit at the low sync speed until you actually resync it

What's the best way to get a proper re-sync?

I'm worried rebooting the router will have a bad effect and possibly somehow the exchange will see it as a fault. I know you mentioned it being ok to do it in moderation but I tried it a few times when the sync dropped out but it kept coming back to the low 1780kbps.

Would leaving the router off for a length of time be of any benefit?

1. If the noise margin is low then no point in trying a resync
2. Only resync once there is lots of spare noise margin

Or if still unsure, then one resync a day during daylight hours should be no problem.