Errors

Started by Tacitus, May 07, 2008, 09:17:32

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Tacitus

Not strictly an iDNet topic but still.

At around 7-8am and 6-7.30pm in the evening (maybe at other times, but I can't check) my modem reports massive errors.  These are not enough to always trigger a resync but the SNR goes up to the 13/14 region.  Once the errors stop it drops back to its more normal 11dB.

I've done all the usual - mod faceplate, Cat 5 to the modem socket, twisted pair modem cable etc.  Also I have a power smoothing block in the mains supply so I doubt the troubles are mains borne.  It's possibly RF or, more likely line problems since this is a poor quality line - I'm in a village and BT admit the lines at this end are poor, but decline to do anything since voice works OK.  Normally I would expect a sync at around 3.5/4.5 given the distance, but not much hope of that.

I think the line is failing over time, since I originally got a fairly stable 2500 profile when max was introduced.  BTW I'm on Demon and reluctant to call Bangalore...

Any ideas?

Modem is a Zyxel 662H (AR7 based)

Stats: 9.04am today

noise margin upstream: 19 db
output power downstream: 15 db
attenuation upstream: 31 db

noise margin downstream: 12 db
output power upstream: 11 db
attenuation downstream: 55 db

BT Check:  9.04am today

IP profile for your line is - 1750 kbps  (Bit low, as I generally manage 2000kbps)
DSL connection rate: 448 kbps(UP-STREAM)  2016 kbps(DOWN-STREAM)
Actual IP throughput achieved during the test was - 1301 kbps




Rik

Hi Tac

Are you sure you're not re-synching? Noise margin will only go up if you've synched when there's a lot of noise around and then it stops. IOW, when you see the margin go higher, it's actually a sign that there's less noise around not more.

You're synching right on the bottom edge for a 1750 profile, and your throughput is quite low for the profile, so I suspect you've got a lot of errors on the line - can you get that info from the router? If not, ask your ISP, they should be able to see the count.

To put your line in perspective, I have a 56.8db attenuation and sync at 3520, so either the router is an issue or there is a big noise problem. A 2700 might help in the first instance.
Rik
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This post reflects my own views, opinions and experience, not those of IDNet.

Tacitus

Quote from: Rik on May 07, 2008, 09:24:17
Are you sure you're not re-synching?

Dont think so as the router timings don't suggest I am.  It currently says I've been up for 30 hrs.  Last time it resyncd was at aroung 4am the other morning which could have been BT playing around.

Quote
You're synching right on the bottom edge for a 1750 profile, and your throughput is quite low for the profile, so I suspect you've got a lot of errors on the line - can you get that info from the router? If not, ask your ISP, they should be able to see the count.

The only errors the router reports are those I have quoted.  It's not reporting any at other times I've looked, but it may be they are bursts and I've missed them.  Do you know of any continuous logging utilities, preferably Mac based but I could fire up the PC and use that.

QuoteTo put your line in perspective, I have a 56.8db attenuation and sync at 3520, so either the router is an issue or there is a big noise problem. A 2700 might help in the first instance. 

I might try going back to the Draytek.  The two wire routers look good but AFAICT none of them do VPN or port mapping.

Thanks for the help.

Rik

Does the router specifically log disconnections, Tac? IOW, it the up time report for the router or the line?

Sorry, can't help with any Mac software, hopefully someone else can, but can you Telnet into the router to get at more info?

I found my Draytek 2600+ was worse than a Netgear on Max. Would you be better off moving to a fixed-rate 1Mbps service and gaining stability at the loss of some speed?
Rik
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This post reflects my own views, opinions and experience, not those of IDNet.

Tacitus

Quote from: Rik on May 07, 2008, 09:40:31
Does the router specifically log disconnections, Tac? IOW, it the up time report for the router or the line?

It does both but I gave you the line up time.

Quote
Sorry, can't help with any Mac software, hopefully someone else can, but can you Telnet into the router to get at more info? 

It is possible to telnet but I'm not sure what info you can get.  I'll have a look and see if anything looks like it might be useful.

QuoteI found my Draytek 2600+ was worse than a Netgear on Max. Would you be better off moving to a fixed-rate 1Mbps service and gaining stability at the loss of some speed?

I have a 2800 and with some tweaking it wasn't too bad until there were massive errors on the line and it refused to sync for more than 10 mins.  That was when I went to a Zyxel which synced straight off, and to be fair it's not been any trouble.  It also does VPN and port mapping, albeit via CLI, but I can live with that. 

I'm reluctant to go for a fixed 1Mb.  TBH I'm waiting for my 12 months with Demon to expire and I'll then consider my options.  iDNet for instance would be able to look at the connection and see whether there is noise or not.  I know a move elsewhere won't solve the poor line since it's BTs problem, but communicating with people who know what they are doing would be a big help.  Demon are OK if you get a good one, but it's luck of the draw.


Rik

Quote from: Tacitus on May 07, 2008, 09:52:37
Demon are OK if you get a good one, but it's luck of the draw.

Unfortunately, that's the problem with so many iSPs these days. :(
Rik
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This post reflects my own views, opinions and experience, not those of IDNet.

Tacitus

#6
Quote from: Rik on May 07, 2008, 09:54:59
Unfortunately, that's the problem with so many iSPs these days. :( 

Too true!

Just a thought.  Do you  know if 2-wire do a plain modem?   No router, no firewall, a straightforward modem with an ethernet port.   I've looked but can't find one.  On the assumption this would perform as well as the 4-port router variants, I could try one with a separate firewall.  Probably need a little more wiring, but since I live in a bungalow that's not too bad. 

Edit:  I'm not bothered about VoIP, but need VPN/port mapping

Rik

I don't know, I've certainly never seen one on this side of the pond. As they don't have a retail channel here, even if they do make one, it would probably be hard to get hold of. :( The other brands to try would be a Speedtouch or a Netgear 834v4.
Rik
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This post reflects my own views, opinions and experience, not those of IDNet.

Tacitus

Thanks for that Rik.

Aren't the fixed 1/2Mb services simply Max with a cap?  Or are they the old style (non max) fixed?

Rik

The old-style fixed services are still available, though increasingly rare. The reduction in the u/s sync speed can sometimes help as it reduces cross-talk in a 'worst case' scenario.
Rik
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This post reflects my own views, opinions and experience, not those of IDNet.

Sebby

Quote from: Tacitus on May 07, 2008, 12:32:57
Aren't the fixed 1/2Mb services simply Max with a cap?  Or are they the old style (non max) fixed?

Some ISPs offer Max with a cap and call them something different, but IDNet are able to get you a true fixed service.