Attainable Rate Vs. Sync

Many of the ADSL2+ calc sites show my 'attainable rate' as 71xx bps.

Is attainable rate the theoretical max speed, or their estimate of what my sync should be?

My max speeds are 6750bps. My sync is 8128. Estimates from calc sites have my distance from exchange between 2.1km and 2.5km (this is calced on D/S attenuation only).

D/S - Attenuation 30.0, noise margin 8.0, output power 22.

U/S - Attenuation 19.0, noise margin 9.5, output power 10.


This is posted in PN forum, because I would like a PN rep's take on that too.

Ta!

All the speed calc sites I've come across estimate your Sync Speed. I don't know which one calls it 'attainable rate'.

What do you mean by your "max speed of 6750 bps"? I take it you mean your throughput and it should be in "Kbps". If so, it is correct for your Sync.

On ADSL2+ you would get about 15 Meg Sync, but you are on ADSL1 only.

In reply to a post by XRaySpeX:

All the speed calc sites I've come across estimate your Sync Speed. I don't know which one calls it 'attainable rate'.

What do you mean by your "max speed of 6750 bps"? I take it you mean your throughput and it should be in "Kbps". If so, it is correct for your Sync.

On ADSL2+ you would get about 15 Meg Sync, but you are on ADSL1 only.

I think OP might be talking about profile versus sync perhaps? Or maybe a calculation that estimates overheads (such as ATM headers etc), to estimate real throughput speed?

@OP
http://www.farina1.com/adsl comes up with some nice estimations in that regard

Edited by deleted (Fri 24-Jun-11 14:59:20)

My max speeds ...

reported by what ?

I thought 7120 was the actual data throuput if your sync was 8128 so 6750 sounds as if something in the network (BT or ISP) which is capping the traffic throughput.


(sorry, don't have sigs displayed but from post seems you may be elsewhere)

Or maybe the state of play at The Oval!

It could be anything. He is so vague and imprecise

In reply to a post by XRaySpeX:

It could be anything. He is so vague and imprecise

Or perhaps I don't know what "attainable rate" means. C'mon, think about it.

Right:

http://www.kitz.co.uk/adsl/max_speed_calc.php

At 30dB it gives a profile of 6500, which is tosh. My profile is 7150.


Attainable rate - http://forums.whirlpool.net.au/archive/626639

Attainable rate - http://mbni.blogspot.com/2010/07/low-attainable-rate...


Based on that and one or two other links, it seems to be the profile speed. No matter.

In reply to a post by camieabz:

At 30dB it gives a profile of 6500, which is tosh. My profile is 7150.

Kitz is only an estimate, based on average readings, incl. noisy lines that have not been optimised! IP Profile goes up in steps. Your Sync is significantly higher than that estimated by Kitz, sufficient to move your Profile up by 2 steps.

As for "Attainable rate", in a router, not on a calc site, it is the theoretical max. rate the router calculates it could achieve on your line and is higher than the actual Sync rate achieved. As your 2nd attribution attests! It is never the IP Profile, but you know you have to take what is written on the Web with a pinch of salt..

Here's one I prepared earlier:

www.camieabz.co.uk/adsl2.png

Basically I roughly estimated the distances or attenuation on the x-axes then drew a lineup, then across as it intercedes the ADSL2+ curve.

From left to right (approx speeds and to the nearest 250kbps):

13000, 14750, 15500, 18250, 10000, 11500, 14000.

Now I appreciate that all estimators should be approximate, but surely there ought to be a touch of consistency with the graphs.

Just making a point of how all these sites differ when estimating speeds. I know it's just an estimate, but why are they all so different?

You don't say which site is which.

No. No point in that. The focus is not on "this site is wrong". The focus is on "all sites disagree". Naming one or more sites would be pointless.

If you want the sites, just pop in "ADSL2+" in google and search for images.