New long reach activation - working, but problems

A few days ago I finally managed to successfully receive an ADSL service on my long (~8km) line, on my third attempt over the course of two years and after BT marked my line permanently unviable (which, amusingly, the BT Total Broadband checker seems to think it still is). I'm using MaxDSL via Plusnet's LLU platform on the Guildford exchange, as I thought this combination would give me the best chance of averting BT's glance, after being rejected instantly for Zen's 256k service when I applied last year.

Now I've just about overcome the initial shock of it actually working, I feel it's time to address a few issues I'm experiencing. I should point out that even if these aren't resolved I would be perfectly happy with the service, as it's infinitely better than 56k and the satellite connection I was sharing until Ouranos's untimely demise for all purposes except downloading large files.

The first is that even though I've been syncing at various downstream speeds between 500ish and 850ish (will explain below), my download speed when the connection is otherwise inactive invariably peaks at 29K/s, give or take no more than a couple of hundred bytes/sec. In fact, upon running the adslguide speed checker last night I found my download capacity was around 235kbps, as expected, but my upload was about 375kbps.

I have no idea of the technical reasons which could result in such a disparity, hence my posting here, but my immediate intuition would be that my downstream is being artifically restricted to to 256kbps whereas upstream is unaffected.

Secondly, I find that my ping spikes massively whenever I'm receiving any data. While I realise this is to be expected to some extent, I never thought that every single HTTP request would be so disruptive, and since one of my primary reasons for seeking a low-latency solution all these years is online gaming (yes, I realise how unpopular this makes me with other users) it could be a bit of an issue if I lag out every time someone loads a web page on the other computer. Through experimentation I've found that the sweet spot for throttled downloads is about 8k/s, and at this or below almost all pings get through in the expected time, but unless I build a dedicated routing box or get a router with bandwidth restriction capabilities I won't be able to do much about it.

According to my router, interleaving is enabled, and ideally of course I would like this to be turned off but I assume that since my line is so marginal it may fade completely into non-existence if interleaving is disabled. So is this problem simply an unavoidable consequence of my low downstream capacity and interleaving?

Here are some details of my setup and connection status, not sure what most of the other router statistics mean but if any further information is necessary than please let me know.

• Router is a Guru GART2-4115 (apparently rebranded Safecom SART2-4115, details here) which I've borrowed from a friend for testing purposes, since I assumed there was no chance whatsoever of it working and that I'd be returning it in a couple of days. Only using it as a modem with my Linksys wireless router as router because my cables aren't long enough to do it the other way round, but I've tried connecting directly to the ADSL router and it made no difference to the above problems.
  
  I know a couple of years back there was talk of specific routers being friendly towards and sometimes having specific firmware for long lines, is it possible I could get better results with something else?
  
  
• Needed to install filtered faceplate to achieve sync, absolutely nothing happened until I tried the test socket.
  
  
• Sync speed - the very first time I synced, it was at 400/300ish, and the second time downstream was 500ish. Every time since then, DS has been either 6xx or 8xx, and US is always 448, apart from most of today when it dropped to 320, only returning to 608/448 in the past hour or so. So alot more than 235 downstream then.
  
  
• Noise margin - upstream has always been 10 until earlier today when it went down to 6, coinciding with the sync speed dropping from 448 to 320. Downstream is all over the place - typically 5-7 when syncing at ~600, as it is now, but when I sync at 800+ it's much worse, sometimes as high as 5 but often 1-3, and on a couple of occasions even going into negative overflow with an 8-digit plus figure.
  
  Should probably point out here that I don't think I've ever had any interruptions to the service that aren't attributable to other factors (usually wireless dropping out as I've had to move the wireless router so the cable can reach the modem). Will need to test over a longer period to see whether that stays the case.
  
  
• Attenuation - has always been 63 down/31 up, never seen it change.
  

Thanks very much for taking the time to read this incredibly long post, and please don't hold back if it's all bad news - after being rejected even for ISDN on the basis of my line length, I'm just pleased that I have something that isn't analogue/satellite...

You are at the end of a very long line (this you know), take a quick gander through this thread.....It may sync, but it'll less than reliable, to put it politely.

You could try a DrayTek 2600 modem/router with the UK2 firmware written specifically for bad lines.

The 2600 is still available from DSLdepot at a very competitive price.

Thanks very much for the replies, didn't think of looking in the "General Broadband Chatter" forum.

Remember reading about the attenuation cap problem now, so presumably mine is even worse than indicated. I reiteriate that I've never noticed loss of sync though, and my actual downstream speeds seem to be better than Garret's, though otherwise my problem sounds very similar to his.

So I'm better off with standard RADSL than Max then, even at 512 rather than 256? Bearing in mind that BT still officially claim that my line doesn't support ADSL.

Draytek 2600 was the model I was looking at a couple of years ago, will go for one of those (any advantage in Plus if I don't need the additional functionality?), unless the Speedtouch mentioned in the other thread is considered better.

Any ideas about ping/interleaving? If I'm not going to get more than 29k/s out of my connection regardless then I don't mind sacrificing a little more speed to get a lower ping, provided that it doesn't affect the stability.

The Draytek 2600 has a good reputation for stability on long lines, and indeed I have one myself, however a recently bought BT Voyager 2000 seems to be more stable on my line, with 24 days and few errors connection straight away. Where-as my Draytek can disconnect anywhere from after a few hours to after a fortnight, with loads of uncorrected block errors building. Just an observation.

Btw, my line stats are 2Mbps connection with 49dB attenuation, and 12-16dB SNR Margin depending on time of day. Not sure if it's worth the possible hassle of trying Max, as I may not get a 2Mb connection back again with my stats...

Also, I've tried both Drayteks normal and long-line firmware versions with no obvious difference, though I have to say the Draytek is way more stable than the Speedtouch 530 I had, and also a Zyxel 650.

Edited by dieselglider (Tue 24-Oct-06 18:24:28)

Fortunately the newer Speedtouch routers (e.g. the 5x6 series) are far better.
I've a Speedtouch 546 on a 57db line and can sync (during daylight) at 4096kbps, with a noise margin of 6db. However, due to higher nightime noise, this higher sync usually doesn't hold for more than a day or two.
If I deliberately sync at night, it'll sync at 3600kbps+ (again with a 6db margin) and stay there for weeks.

I have similar figures from a shorter line - 5.9km, 62dB D/S attenuation, 31.5dB U/S running ADSLMax - interleaving turned off manually.

I get approx 1.5Mbps on my link and have tried a few different routers:

Origo 8400 (almost identical to your Safecom)
Westell 6100
Westell 6301
Speedtouch 516v6

I would recommend you try a 516v6 which seems to work well using the latest UK firmware - it reports an alarming amount of errors compared to the other routers but seems very stable. A bonus is that you can pick them up from DSL Depot for

Edited by GavinP (Wed 25-Oct-06 13:51:11)

Sorry, didn't see your reply as email notification still seems not to work - thanks for the advice, will go for one of those I think. Same wireless router as me too...

It seems the ~288kpbs downstream was a result of the initial training period since I'm now getting up to about 60k/s download, and one of the plusnet tools (which I now can't find) is indicating that my connection is 500kpbs, presumably it was ~256-288 before. I'm more than happy with that and would never expect any more on a line as long as mine, so that just leaves the question of interleaving - very encouraging that your stats are similar to mine at such speeds with interleaving off, just not sure how easy it will be to re-enable if it all goes wrong.

Actually, through a complicated and improbable set of circumstances for which I refuse to take total blame it may already be disabled as soon as my training period ends...