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Poor upstream sync speed

acorns
Grafter
Posts: 29
Registered: 31-10-2007

Poor upstream sync speed

Does anybody else have an issue whereby downstream sync speed it good, but upstream is not?
I have a particular problem with a ticket open at the moment, though no reply from PN in the last 24 hours. For several weeks my router has synced downstream at around 5.5-6Mbps (fine), whilst the upstream speed has been resolutely stuck around 64kpbs. Tried two other routers with the same results. After raising the fault  with PN yesterday the basic broadband checks were carried out, both by them and me (master socket, new filter, disconnect phones etc). Whatever PN did resulted in my router correctly syncing upstream at 608kpbs late yesterday. Problem solved I thought, until 16.30 today when I had a disconnection and resync at 96kbps (downstream was still 5500kbps as expected). I don't see how a fault on my line could cause this behaviour. It may be related to an ongoing problem I seem to have of frequent disconnects, but with the router still reporting sync but with the ppp session not always authenticating by itself without a router reboot.
This is driving me a bit mad. I've tried 3 routers of different brands and they all sync at varying low upstream speeds.
16 REPLIES
Community Veteran
Posts: 38,460
Thanks: 1,030
Fixes: 62
Registered: 15-06-2007

Re: Poor upstream sync speed

As a fellow sufferer (now fixed after a ticket chain lasting from May to July) I can sympathise - mine only went down to 192kbps with the downstream rate unaffected.
Can you advise the upstream noise margin, attenuation and synch speed.
Also if you connect to the master socket (with the lower faceplate removed) without a phone connected does a resynch give better figures.
If the speed goes up to 448kbps in this test with a high noise margin try resynching while ringing in (I used my mobile) without a phone connected - does that make a difference.
acorns
Grafter
Posts: 29
Registered: 31-10-2007

Re: Poor upstream sync speed

As of this moment my settings are...
Downstream    5472kbps  Noise Margin 12.1dB  Attenuation 39.0dB
Upstream        96kbps        Noise Margin 13.0dB  Attenuation 24.0dB
The Noise and Attenuation settings are also fairly typical of when I have a good connection in both directions. Downstream usually connects anywhere between 5500 and 6500 kbps.
My master socket doesn't have a faceplate, its the older style one that looks like any other socket, albeit with the extra components on the back. Would replacing it with a modern NTE5 socket make a difference? I didn't think that householders were allowed to interfere with the master socket anyway short of removing the faceplate if you have it?
Also, I thought that 448kbps was the maximum upstream speed, so why does my connection (when it works!) sometimes go as high as 608kbps?
Community Veteran
Posts: 6,735
Thanks: 12
Registered: 02-02-2008

Re: Poor upstream sync speed

Hi acorns. Is there any extension wiring from your master socket?
Community Veteran
Posts: 38,460
Thanks: 1,030
Fixes: 62
Registered: 15-06-2007

Re: Poor upstream sync speed

The odd part about those results is the upstream noise margin. As far as I know the upstream noise margin defaults to 6dB on a BT line. Note that the upstream noise margin is only recorded at the time of synchronisation and subsequent changes don't appear as the router doesn't see them.
With respect to the master socket you are correct that you shouldn't replace it.
If you disconnect all other devices from the phone line and the problem persists then I believe you will have done everything you can and it's a question of getting BT out. Perhaps a PlusNet rep can confirm this.
Going back to your original post - unless you are on the business connection with a higher upstream rate I don't see how you can get 608 kbps. I assume that you are not on the LLU connection and in which case something is badly wrong.
acorns
Grafter
Posts: 29
Registered: 31-10-2007

Re: Poor upstream sync speed

I've now got every piece of extension wiring disconnected and just my router and a phone left on the master socket. Have been down this road before though and don't think its going to make any difference.
I believe that I AM on the Tiscali LLU since my first tracert hop is always to 'lo0.plusnet.thn-ag2.plus.net', which I believe is Plusnet's LLU pipe to Telehouse North. I've always had my suspicions about the Tiscali LLU. I had persistent problems a couple of years ago which were finally identified as a Tiscali fault at the exchange (not as a consequence of my Plusnet ticket at the time though). Another reason I suspect it is that my Father-In-Law is a recent Plusnet subscriber (referred by me) on the same exchange with the same router and he has had a rock solid connection at about 5Mbps for months now with not a single disconnect. It is likely that he will be on BT equipment at the exchange since Plusnet no longer migrate to Tiscali. Not a very scientific comparison I know since line quality factors are the most important thing. You should see some of his wiring though!
Plusnet seem to be uncommonly slow responding to me about this, and its getting frustrating.
Community Veteran
Posts: 38,460
Thanks: 1,030
Fixes: 62
Registered: 15-06-2007

Re: Poor upstream sync speed

I know this isn't directly addressing the problem but I believe that PlusNet will give you a free transfer back to BT.
If so this is one way out of the problem as that will involve changing some wiring/jumpers at the exchange. In any case I think BT Opereach are more responsive than Tiscali.
There aren't any PlusNet staff on the forum at present but if you wait until Monday then see who is here (bottom of the forum home page) you could try sending them a PM. This often brings it to peoples attention and gets something moving.
Community Veteran
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Registered: 02-02-2008

Re: Poor upstream sync speed

Quote from: acorns
I've now got every piece of extension wiring disconnected and just my router and a phone left on the master socket.

Could you post the stats again please.
Community Veteran
Posts: 38,460
Thanks: 1,030
Fixes: 62
Registered: 15-06-2007

Re: Poor upstream sync speed

and also with the phone disconnected if that makes a difference
acorns
Grafter
Posts: 29
Registered: 31-10-2007

Re: Poor upstream sync speed

Thanks for the responses chaps. I'm actually at work now, so can't do any more testing today. I've had a response from Plusnet support in which they have offered to switch me away from Tiscali LLU and back on to BT, so I've taken them up on that. They've tried various line profiles which always resulted in sync at 64kbps.
Interested about the comment that I shouldn't be able to achieve 608kbps upstream speed, since I didn't think I'd be able to either. I'm on BBYW Option 1 (the cheapest PN package!) . Plusnet told me on the phone the other day that I should sync at 448kbps. I'd have believed that my router was misreporting the speed other than that I actually managed to carry out a speed test when synced at 608kpbs, and got an upload speed in excess of 500kbps, so the router must have been right! If 448kbps really is the maximum then something must be misconfigured somewhere, hopefully in Tiscali who I shall now be leaving!
Community Veteran
Posts: 6,735
Thanks: 12
Registered: 02-02-2008

Re: Poor upstream sync speed

I believe the Tiscali LLU kit has different constraints, and I wouldn't be surprised if they've configured it wrong.
Even BT's kit CAN go faster on upload (if you pay them to turn the option on) - I know, I tried it about 6 months ago.
acorns
Grafter
Posts: 29
Registered: 31-10-2007

Re: Poor upstream sync speed

A quick update.
Just after noon today my connection was transferred from Tiscali LLU back to BT.  Connection was down for a couple of minutes and then my router immediately resynced at 6944kbps downstream and 448kbps upstream. Interestingly my SNR margin is now at the expected default of 6dB rather than just over 12dB where it always was with Tiscali, which has given me a useful extra 1Mbps downstream without having to manually adjust the router SNR settings to achieve this.
So, looking good so far. I don't think my Tiscali connection was ever set up properly to allow me to achieve best results from my line, and hopefully has been the root of my problems. Glad to see the back of it. The only real benefit it had was the capability to sync upstream at 680kbps maximum (when it worked!) rather than BT's 448kbps.
I'm not certain of the actual reasons why Plusnet halted migrations to Tiscali LLU, but thanks to them for a free transfer back to BT. I actually only asked them whether or not I was on Tiscali without ever asking for a transfer back. Perhaps the fact that one was offered with no prompting indicates that issues simliar to mine have been identified with other LLU customers.
Community Veteran
Posts: 14,469
Registered: 30-07-2007

Re: Poor upstream sync speed

As the OP has already moved the info below is for other Tiscali users like myself....
The default target SNR on Tiscali LLU connections supplied by PlusNet is 12dB compared to BT's 6dB, which would result in a lower sync speed both upstream and downstream compared to BT. There is also no IP profile as such and all connections are normallt set within the PlsNet systems to ither 8000 or 7150.
It is however possible to change your profile to one that has a 9db or 6db target SNR - I am currently on a 9dB profile - if your line can cope with it. Just raise a ticket and ask for whichever profile you think your line can support. If it gets too bad you can just get it switched back again.
The number of people still on the Tiscali LLU connection seems to be reducing week by week and eventually either all users will have asked to be moved or Plusnet will move everyone anyway sometime in the future.
The reason the Tiscali transfers were suspended and then stopped was due to a higher number of faults initially and then the takover of PlusNet by BT. BT are not going to sell a competitors product are they Wink
acorns
Grafter
Posts: 29
Registered: 31-10-2007

Re: Poor upstream sync speed

What would be the reason for 12dB on Tiscali and 6dB on BT?
I can only assume that Tiscali does not utilise such sophisticated line management as BT (allowing the margin to be dynamically altered up and down automatically) and therefore the level is deliberately set conservatively to minimise connection issues. Seems a shame if it is because of the obvious lowering of sync speed.
Community Veteran
Posts: 14,469
Registered: 30-07-2007

Re: Poor upstream sync speed

Tiscali's line management is much better than BT's in my opinion. Your sync rate is your data rate - that's it..., no messing about with constantly changing IP profiles every time you sync at a different rate. If you get a low rate just resync and it returns to normal. It may not be as fast as on a BT line but I have found it far more reliable since I moved.
The 12dB figure is the standard that Tiscali use for all their LLU connections as far as I know, as it resulted in less problems overall, especially on longer lines, than BT's figures.