Interleaving vs Fast-Path

Hi all,

My broadband connection was changed to Interleaving about a year ago to improve connection quality and performance. At the time we were not using an ADSL2 compliant modem and therefore the experience was not all that great anyway.

However we now have a ADSL2 router and ever since using this our speed has increased from a 3mb connection to a 6mb connection.

Does anyone know if it is possible to turn interleaving off on my connection or I am asking for trouble. I believe my old 3Com router referred to this as FastPath.

My ISP is Orange and I have yet to receive any response from them on the matter.

My other aim from this is to gain increased ping times and improve latency.

Does anyone have any feedback or guidance with this?

Many thanks.
Phil.

I thought Orange used ADSL1 (what ADSLmax is really)?
In any case, if you don't do a lot of on-line gaming (and don't need super fast pings), stick with interleaving (as it can often improve data throughput, by correcting errors that otherwise would require retransmission).

My other aim from this is to gain increased ping times and improve latency.

Well you're on the right ISP if you want to increase ping times
Surely you mean decrease ping times, and latency?
In which case, just switching ISP may help.

You don't mention your pings (with Orange); but as a comparison, mine are around 32ms to www.bbc.co.uk (with interleaving on) and around 16-18ms with interleaving off.

Hi Ade,

Thanks for your feedback on this.

Sorry my mistake. I did mean decrease ping times.

Just did a ping to bbc.co.uk - Average of 31ms over 20 pings.

My next research project is a case of who to move to - I was thinking about Plus Net.

Phil.

Sounds like your original problem was the router itself. Irrelevant now.

A few things before you talk about a new ISP - though you should certainly do that.

If you can post your line stats it would be useful - particularly sync, attenuation and noise margin (SNRM), and error stats including FEC, HEC, CRC. The error stats over as long a period as possible are a guide to whether or not you can live without interleaving and the other stuff tells us a lot about your line quality.

If you can find your master socket and it's an NTE5 where the bottom half of the faceplate comes off - 2 screws - then after the above open it up and connect into the test socket revealed. Then get your line stats again immediately. We want to see if there is a significant difference in anything. (There will not be a difference in download speed at this stage so don't bother trying a speed test).

While you have it open, or even if it isn't an NTE5, have a look at this site and do what it says. I got someone with a "bad" line to do that yesterday and his sync went from around 2000kbps to 4960 straight away. That sort of change is rare, but useful increases are normal.

Finally, what's your exchange? So we can see what is available to you. Look here if you don't know. It's where I'm going to look when you tell us - but it's a lot of info to cut and paste.

Hi there,

Line stats as it stands are below :-

Stream Type Actual Data Rate
Up Stream 448 (Kbps.)
Down Stream 6304 (Kbps.)

Operation Data Upstream Downstream
Noise Margin 20 dB 8 dB
Attenuation 46 dB 36 dB

Indicator Name Near End Indicator Far End Indicator
Fast Path FEC Correction 0 0
Interleaved Path FEC Correction 5168 89034
Fast Path CRC Error 0 0
Interleaved Path CRC Error 67 627
Loss of Signal Defect 0 ---
Fast Path HEC Error 0 0
Interleaved Path HEC Error 136 0

This is through the normal connector and will do it this again a bit later through the master socket as it is not convenient to do this at the moment.

This is the exchange :-
http://www.samknows.com/broadband/exchange/WWREDR

That's great, any idea how long since that was sync'ed? Just a guide to work out the error rate.

The current connection started this morning.

2008.03.29 09:37:04

That's good, hundreds of thousands of FECs seem to be quite common in that time-scale.

Interleaving reduces packet loss, which is why latency goes up so it can re-assemble stuff. The FEC count is the number of corrections the router has made.

On Fast Path those errors would have needed a retransmission of the packets. Quite at what point that cancels out the advantage of the improved latency I don't know, but I would imagine you would be fine with those rates.

No doubt others who do know will be able to comment.

Thanks for your comments on this.

Much obliged.