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Up to 8Mb? What's the reality we can expect

Dizzley
Grafter
Posts: 275
Registered: 17-04-2007

Up to 8Mb? What's the reality we can expect

I chose to upgrade to MaxDSL on the understanding from the marketing and technical information on the PlusNet that the bandwidth will be "up to 8Mb". What does that mean to my connection? It seems to me that my connection is being managed by factors unknown. My web browsing speeds/quality are suffering. Are yours? I'm also suffering lots of web timeouts. It's like being back on dialup.

Did anyone else assume they were being offered a quite different "up to 8Mb" service? Or did you expect the wild west, where we all fight for contended bandwidth?

Now I have no problem with some variation in speed, but what might affect the achievable speed?

    - Physical sync rate on the line? Fair enough: if my line can't cope with more than 4Mb I would expect to see it sync at 4Mb.
    - The formalisation of that physical speed limitation as Max Stable Rate (MSR). Again, fair enough: a well chosen MSR will keep everyone happy.
    - Contention at the exchange? Mmm. I'm not so happy about that but I can live with it. My exchange appears to be green constantly. Some aren't PM (Post Max).
    - Contention in the BT network beyond the exchange? Less happy about this one. You take the money BT now get some kit in.
    - Contention on PlusNet pipes? Well, demand has just basically quadrupled. I hope that PlusNet have planned increased capacity. Capacity Management anyone? The summary graphs seem busy but not full so I don't expect to suffer on that account. I expect 50:1 contention. Will I still get it? I'll move ISP to solve that one for the right price.
    - BT "network management"? I hope that doesn't mean swinging my speed up and down like a yoyo even when there is no contention visible.
    - PlusNet "network management"? I understand that this just means I must keep in the "managed peak time usage allowance" figures, as discussed elsewhere.

In summary: what will be the limiting factor for most consumers' speed on MaxDSL?

I would expect only the smooth application of contention to moderate my effective browse/download rates at peak times. I don't expect it to be like someone flinging a switch off and on the whole time.

Time for bed and my medication....Nurse!
6 REPLIES
Community Veteran
Posts: 14,469
Registered: 30-07-2007

Up to 8Mb? What's the reality we can expect

Your line condition (line attenuation & signal to noise ratio) is the limiting factor for ADSL itself, not just MaxDSL and in plain speak, the further away from the exchange you are the lower the signal quality and thus the lower the achievable speeds are.

If you know your line atten & SNR, put them in http://212.23.23.177/calc.htm to get a very rought estimate of the sync speed you are likely to get.

Also see ADSL: Understanding Line Loss and measurements.
Dizzley
Grafter
Posts: 275
Registered: 17-04-2007

Up to 8Mb? What's the reality we can expect

Hi Peter,

My router figures:
ADSL Link        Downstream 	Upstream

Connection Speed 8128 kbps 448 kbps
Line Attenuation 21.0 db 10.0 db
Noise Margin 8.4 db 23.0 db


which is comfortable for 8Mb. It never disconnects, never shows CRC or other errors. I disconnect for 2 minutes every day.

My effective speed swings between 500k and 6M (3900k right now at 0019h). Plus lots of web timeouts.

I just wonder if I'll ever see speeds near 2Mbit at peak times again. I'm sure there's no exchange contention reported on the exchange checker. I think BT's network may be creaking at peak times, or having a hissy fit trying to bounce everyone's speeds around.

(AdditionSmiley
So, how's my 50:1 contention lookingHuh

This is approx Day 7 of my upgrade though.
N/A

Up to 8Mb? What's the reality we can expect

I dont think it should make any difference but what DNS servers are you using ? This may account for some of the timeouts (although as I said it shouldnt make any odds at all).
Dizzley
Grafter
Posts: 275
Registered: 17-04-2007

Up to 8Mb? What's the reality we can expect

DNS on my PC is
212.159.13.49 and 212.159.13.50.
My router gets DNS from PN and uses
212.159.6.10 and 212.159.6.9.
My PN connection details recommend:
212.159.13.49 and 212.159.13.50

What do you recommend for DNS server?

Also, if I can't achieve 8Mb with this kind of connection who can?
Community Veteran
Posts: 14,469
Registered: 30-07-2007

Up to 8Mb? What's the reality we can expect

All 4 DNS servers listed are fine and you can use any combination of the 4 IPs.
N/A

Up to 8Mb? What's the reality we can expect

I have my router permanently set to use

212.159.13.49 & 212.159.13.50

My is also hard set to use those DNS ip's as well as two more which are being hosted by a mate at present. I will be setting one up of my own soon and so we act as each others secondary DNS server ( if this makes sense ).

Those stats dont look bad at all if im honest with you, but then im merely looking at the stats and can only comment on them.

Have you tried leaving your router off for an hour? Have you rebooted your router once every day for 3 days?
I am not implying this will make any difference. I am merely passing on a common myth or belief in this forum which may ( or also may not ) benefit you in some way. I found that interleaving was turned on during the training period but then on day 6 it got taken off again and now I have a reasonable enough connection at around 4500 - 5000 ( downloading maxing at about 420Kb/s ).

As Peter has said in other threads, it may be best to wait till day 12 and then kick up a storm in a teacup ( so to speak only ) as technically you are still within the training period and so nothing untoward could be deemed by this :?

Regards,