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Hi
Sorry to do another one of these stats posts but I am considering jumping from eclipse to be* as I am experiencing very bad quality of service recently. I am not entirely clear when this started but I did have a BT fault on my line recently which they resolved (but never contacted me to tell me what the problem was).
Previously I had always just looked at my router connection speed as a guide but reading around these forums I see that attenuation and noise margin are also important and this tallies with what I am seeing that upload speeds are good and download is bad. Heres my stats - all comments appreciated.
Downstream
Connection Speed - 5792Kbps
Attenuation - 46db
Noise Margin - 2db
Upstream
Connection Speed - 448kbps
Attenuation - 13.5db
Noise Margin - 16db
My router is a NetGear DG834G.. it also has the following stats on WAN but not sure if they are relevant:
Tx B/s - 24363
Rx B/s - 43354
Since the PPPoA uptime is less than LAN uptime I am assuming it drops connection sometimes
Thanks in advance
Alasdair
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Your downstream noise margin at 2 dB seems low. Generally Max ADSL is meant to target 6 dB and set the sync speed accordingly. I guess if that falls any lower you will get disconnected and then reconnect at a lower sync speed with a 6 dB margin.
You say this is quite recent. Have you any idea what BT did? Have you ruled out any changes or failings with your internal wiring?
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Thanks john - internal wiring hasn't changed but i will do some unplugging and checking / swapping of filters etc. when I get home.
How can the downstream and upstream figures vary so much?
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I don't know why that is. My downstream margin is currently 16 dB versus an upstream margin of 25 dB.
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upstream is at lower frequency which attenuates less.
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Good - so compared to most other peoples, my download noise margin seems unacceptably low and my attenuation a touch on the high side. This would explain the problem and the symptoms experienced of upload performance being acceptable but download unacceptable.
Bit I am still confused is why my router reports a decent connection speed... this does not equate to throughput I guess.
FYI I get a speedtest.net result of 798kb/s...
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your router said :-
Downstream
Connection Speed - 5792Kbps
Attenuation - 46db
Noise Margin - 2db
if the noise margin got so low (or errors so high) that it had to resync then it might lose a meg or so off the connection speed when it reverted to a 6 dB margin.
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The sync rate is the speed at which your modem and the modem at the exchange communicate. There is a chain of computers between the exchange and the site you are browsing. The weakest link in that chain determines your internet throughput.
To demonstrate the chain on a PC open a DOS window and type
tracert bbb.co.uk
This will show the chain from you to that BBC site.
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Thanks for all your help... I think I understand the problem. So given that everything used to be OK and now things are decidedly bad, what is the most effective way of getting something done?
I am with eclipse and in my experience they will just tell me to unplug the router etc. etc. I am convinced that when there was a fault on my line, something has changed with the set-up.
Given I am considering transferring from eclipse to be*, is this the most effective route as I have read other posts that suggest the transfer process will help (activity at the exchange etc.)
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what does speedtester.bt.com say for your line ?
Also can you expand on what you see as the current problem.
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Have you tried testing at the NTE with all else disconnected as described in the link. The only thing that looks iffy is the 2db ds snr, the sync speed looks there, or there abouts for your attenuation...have you tried a different router ? Have you looked at any ISP specific forums ?
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Gives me the following:
IP profile for your line is - 4500 kbps
DSL connection rate: 448 kbps(UP-STREAM) 5056 kbps(DOWN-STREAM)
Actual IP throughput achieved during the test was - 1977 kbps
(which seems ok i guess...)
The symptoms I have are
1. Frequently receive no response from uk web sites (have to hit refresh)
2. p2p is at a crawl (no settings changed - it used to fly pre this BT line problem)
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Well - not so far... have disconnected everything and relocated router at master socket and still have the 2db margin. As I say, everything used to sing along just fine so I doubt anything has changed with the wiring.
In terms of trying a different router - nope, haven't got a spare one so can't give that a go unfortunately.
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That throughput sucks, you did have P2P disconnected whilst running the test didn't you ?
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Yep - have shut down everything that could be making connections... had active ports to check there is no nasty trojan or something and everything is OK from that respect.
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In reply to:
As I say, everything used to sing along just fine so I doubt anything has changed with the wiring.
I cannot begin to tell you how many times a day I hear that  . You must disconnect everything as shown in the previous link, and retest, you will *hopefully* see an increased snr and sync rate. In my experience there is little in the way of line faults that can actually affect speed, it is usually one end or the other, premises/CPE or the exchange.
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So make a note of them stats, and then retest at the test jack..........
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Sure - sounds like a job for this weekend then!
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How long will it take to remove the front cover and plug in ? Sounds like a job for the next ten minutes !
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Ha - you are right... was trying to do some work but this is driving me mad and want to get it sorted.
So, have done it and plugged in to the test socket... stats are the same. Still that low margin (actually dropped to 1db at one point :-(( "Stable" at a mighty 2db)
PS Thanks for all your help on this
Edited by ajdthomson (Thu 12-Apr-07 21:33:50)
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Is there a high amount of errors showing in the logs ? In theory, with a Max service it should adjust itself to compensate and try and make it's target snr (usually 6db).
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the crawling p2p sounds like Eclipse throttling
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Nothing in logs but netgear router doesn't seem particularly strong there... I am just seeing a constand 2db and very poor service.
So does this sound like a problem at the exchange?
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if you reboot it and its still at 2 dB something is odd. Netgears are famous for drifting SNR results, if the errors aren't piling up on the counters I wouldn't worry about the margin. What flavour of Eclipse are you on ?
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Rebooted router lots of times... mainly a constant 2db, occasionally 3, occasionallly 1.
I am on Eclipse 8mb evolution option 3 (http://www.eclipse.net.uk/index.cfm?id=fixedcomparison_res)
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Yep - could well be p2p throttling... which is fine but I am convinced there is still a problem:
1 - they are clearly not throttling p2p uplonk which can max out (but obviously I have capped it at a sensible amount) out yet downlink is about 2kb/s... never used to be like this
2 - getting the website problems and general poor experience. Also forgot to mention that podcasts never complete... I have to use downthemall on firefox which is capable of restarting.
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