It's noise spikes that corrupt the data so higher noise margins (less noise in relation to the signal) will reduce the number of errors.

Unless you have some specific need for low latency (eg you're a gamer) then interleave will give you better stability and higher throughput on downloads.

I do a fair bit of game playing but im not a hardened gamer by any stretch of the imagination, just thought the the lower pings would be better for me, i ping about 40 to 60 on uk servers interleaved, and approx 20-30 on fast path.
To be really honest though cant see much difference in the lower pings,lol
May go back to interleaved, will give it a few more days

I think it depends on the router as some routers notably the speedtouch misreport errors.

My speedtouch on adsl1 will typically show an average of about 900 crc errors an hour. However I get no packet loss and retransmits.

My experience on interleaving is different however, when I last used interleaving whenever I got a crc error there was a tcp retransmit.

Surely it depends on whether or not the error occurs in a data packet rather than a null packet. If you have a crc error in a data packet it has to be retransmtted - unless you have "holes" in web pages and downloads of course.

>>Unfortunately, I wasn't on 6dB long enough to get around to noting the errors!

If only there was some s/w that could monitor and record things

I know. It's embarassing !

John.

PRTG or MRTG on Linux can be used to monitor any counter that the router makes availble to SNMP but I've not found one that does that for errors it's mostly only bandwith data.
http://www.paessler.com/prtg
http://oss.oetiker.ch/mrtg/


Possibly the routerstats program could be persuaded to graph them somehow but that is really geared to a varying value like snr rather than an accumulating one like error counts. Probably just using it to monitor snr would be a good indicator though as the errors are mostly going to happen when the noise margin falls.
http://www.vwlowen.co.uk/internet/files.htm

I dont know, I can be utilising my full download bandwidth which would surely mean every packet been transmitted is valuable and still have no impact at all from crc errors reported by the router. I dont get issues such as missing images. On interleaving however although the error rate is massively reduced, the errors on that seem to be real errors impacting the connection.

Also my experience with interleaving is actually worse than fast path, I have never tried interleave on ukonline LLU yet, but when I was last using it on entanet I had occasional loss/retransmits whilst a comparable synch rate on fast path there was no loss. My conclusion from that was interleaving seemed to impact bitswapping where the router didnt bitswap anywhere near as agressive as it does on fast path so more tones had negative snr margins, I dont get any tones with negative snr margins on ukonline fast path.

Edited by Chrysalis (Thu 10-Jul-08 10:57:19)

I can't see how you can get a crc without the data having to be retransmitted. Either you aren't seeing those retransmits for some reason or the error reports are incorrect. I'm inclined to favour the former possibility. Then again its your line and you know what works best for you.

IIRC DMT versions that haven't had the tweaking disabled can write it to the (csv) log file. Not got my computer with v8.05/7? on at the moment though.