bk_856er
join:2007-06-08
Palo Alto, CA
| reply to bk_856er
Re: OK stats, but frequent loss of sync
Rather than push EL for 3.0 upgrade, I decided to monitor the line stats for a bit longer and keep some good notes. In my case the limiting parameter is the downstream S/N margin, which generally holds steady at ~15dB. According to e_dub's short test at 3.0 my downstream margin would be 11dB at that speed and basically good to go.
Here's an interesting observation. Thurs/Fri/Mon at exactly 9:00PM PST my downstream margin drops abruptly to ~9.5dB and stays like that for 2-2.5hrs. Then it returns just as abruptly to 15.5dB again. On Sat/Sun this did not occur, so I will tentatively assume it's a weekday thing. All other times of the day also seem to be fine. Line attenuation remains constant. Naturally the diminished margin would be killer on the sync at a higher speed of 3.0, and even at my current 1.5 speed I can see a large accumulation of CRC errors reported by the modem during the low margin period.
I have ruled out interference from within the premises. In fact, the only activity that induces a signal reduction is running the kitchen garbage disposal motor, which is about 15ft from the modem (15dB S/N down to 13dB S/N only while the motor is on). I still need to correlate the nightly line noise spike with possible neighbor activities, but does this pattern sound like something else, such as systematic maintenance on the line/equipment or??
The new modem has been great and the line stability (DMT mode!) and speed tests have also been very consistent. If nothing else, I now have a much better feel for the habits of my line.
Bob |
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DrStrange
Technically feasible
Premium
join:2001-07-23
West Hartford, CT | reply to bk_856er
Ah, sorry. Senior moment.
I don't know if you'd notice static on LPV. I see you've done all the things I would have. |
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e_dub
franknbeans
Premium,VIP
join:2001-08-12
kickin ass
| reply to bk_856er
said by bk_856er  :e_dub: that's still great info to have - thanks! Is my next step to call up EL and request a 3.0 upgrade? Bob Yes contact ELNK. |
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bk_856er
join:2007-06-08
Palo Alto, CA
| reply to DrStrange
e_dub: that's still great info to have - thanks! Is my next step to call up EL and request a 3.0 upgrade?
DrStrange: the thread/story here is sort of long so I will recap for you. A while back the original Zyxel modem at the default ADSL2+ settings started losing sync regularly. Investigation showed the fluctuating margins. Changing to GDMT mode totally stabilized the line. Tried a modern Innoband modem, and although it was stable set to ADSL2+, it only synced at 1.0/384. I changed the Innoband to GDMT mode and got 1.5/384 sync and rock-solid stability, which is where I am at right now. No more fluctuating margins and no more loss of sync.
As part of the original troubleshooting I sniffed the premises with an AM radio, relocated some components and wiring, monitored the margins, etc. None of that changed anything. The dial-tone has no static that I can discern. Something obviously changed or deteriorated a couple of months ago, when the Zyxel ceased to be stable at its default ADSL2+ settings, but I don't know how to track down that issue to resolve it.
Bob |
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DrStrange
Technically feasible
Premium
join:2001-07-23
West Hartford, CT
 ·Stephouse Networks
 ·magicjack.com
·EarthLink
| reply to bk_856er
If your line could maintain 11dB S/N at 3008 downstream, you would be stable at that speed. However, I don't think you're maintaining that margin, since you're losing sync.
Are you getting static on your phone? The description of the 'death spiral' sounds similar to an issue I had several years ago after a nearby lightning strike. I ended up with so much static on my line that voice was unusable and DSL was very slow. I reported the voice issue to AT&T and they eventually moved my line to a different cable pair. |
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e_dub
franknbeans
Premium,VIP
join:2001-08-12
kickin ass
| reply to bk_856er
I only left the 3.0/384 port rated provisioned for 15 minutes. Long enough for me to check for errors and LOS.
Sorry but I can't leave the port provisioned at 3.0 unless there's an order change.
--
Statements made by me are not the views or practices of my employer and they cannot be held responsible for any statements I may make. |
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bk_856er
join:2007-06-08
Palo Alto, CA
| reply to e_dub
said by e_dub :Sorry if you just saw your modem loose sync. I just provisioned your circuit to 3.0/384 because your had very good margins at 1.5/384. Your margins came out to 3.0/384 @ 11.0db/23.5dB I never saw a different sync or transfer speed on my end. I monitored the line very carefully for the last few days and all is well (at 1.5/384). Do your numbers above suggest that I should try 3.0/384? Feel free to respond in the covad direct forum if that's a better place.
Bob |
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bk_856er
join:2007-06-08
Palo Alto, CA | reply to e_dub
You the man! I was actually composing a post in the Covad Direct forum at the time to update you - thanks for your help on this! Keeping fingers crossed...
Bob |
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e_dub
franknbeans
Premium,VIP
join:2001-08-12
kickin ass
| reply to bk_856er
Sorry if you just saw your modem loose sync. I just provisioned your circuit to 3.0/384 because your had very good margins at 1.5/384.
Your margins came out to 3.0/384 @ 11.0db/23.5dB
--
Statements made by me are not the views or practices of my employer and they cannot be held responsible for any statements I may make. |
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bk_856er
join:2007-06-08
Palo Alto, CA
| reply to bk_856er
Using the same "change to GDMT" trick that I used for the Zyxel modem, I was able to get my 1.5/384 sync back along with zippy downloads. I like this modem!
Set to ADSL2+ mode, the downstream attenuation was 52dB and the margin was 9dB and the modem synced at 1.0. With GDMT the values are different as displayed below. This is where I will keep things if everything remains stable. The attenuation makes me a bit nervous. The modem has options to tweak gains and other settings, which I will investigate later...
----
Status
Device Information
Model Name 8860-C1
Host Name home.gateway
System Up-Time 18:29:49s
Current Time Fri, 10 Jul 2009 - 18:59:43
Hardware Version Solos-W ADSL-M v1.00
Software Version 5.52g.dk21.44
ADSL
Parameters
Connect Mode ADSL
Modulation G.Dmt
Profile Type COVAD
Activate Line true
Coding Gain auto
DSP Firmware Version E.25.41.44 A
Connected true
Operational Mode G.Dmt
Annex Type AnnexA
Upstream 384000
Downstream 1536000
CO Vendor GSPN
Elapsed Time 0 day 0 hr 7 min 39 sec
ADSL
Parameters
Downstream Upstream
SNR Margin 15.0 dB 23 dB
Line Attenuation 62.5 dB 31.5 dB
CRC Errors 2 0
Latency Fast Fast
Speakeasy Speed Test after change to GDMT
Download Speed: 1319 kbps (164.9 KB/sec transfer rate)
Upload Speed: 323 kbps (40.4 KB/sec transfer rate) |
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Doctor Olds
I Need A Remedy For What's Ailing Me.
Premium,VIP
join:2001-04-19
1970 442 W30
clubs:
| reply to bk_856er
said by bk_856er :I currently use their PS-15S POTS wall-mount ADSL2+ splitter, but the "advanced filtering" claim of the DSL600-PS unit caught my attention. Maybe it would clean up my line a little and increase my downstream margin? Yes, they make very good products. As to any additional cleaning of the signal above what you already have, I cannot say if that is accurate or just sales talk.  It can't hurt to try unless it is prohibitively expensive. 
--
What’s the point of owning a supercar if you can’t scare yourself stupid from time to time? |
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bk_856er
join:2007-06-08
Palo Alto, CA
| reply to bk_856er
Slightly off-topic, but does anyone have an opinion of this Wilcom device?
»www.wilcominc.com/Item.cfm?ProdID=108
I currently use their PS-15S POTS wall-mount ADSL2+ splitter, but the "advanced filtering" claim of the DSL600-PS unit caught my attention. Maybe it would clean up my line a little and increase my downstream margin?
Bob |
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bk_856er
join:2007-06-08
Palo Alto, CA | reply to Doctor Olds
Thanks for confirming the proper sync behavior. Before I posted here I put an inquiry into Innoband with all the modem data and configuration, so we're on the same page. I see that you are a night-owl like me! |
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Doctor Olds
I Need A Remedy For What's Ailing Me.
Premium,VIP
join:2001-04-19
1970 442 W30
clubs:
| reply to bk_856er
said by bk_856er : I assumed that the modem should sync with the DSLAM port setting, which according to a check by Covad just the other day was 1.5/384... That is what it is supposed to do.
You may need to inquire with »innoband.com/support/contact_support.php
--
What’s the point of owning a supercar if you can’t scare yourself stupid from time to time? |
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bk_856er
join:2007-06-08
Palo Alto, CA | reply to Doctor Olds
I'll swap modems tomorrow. I power-cycled the Innoband and now it syncs at 1.1/384. Weird. I'm no expert, but I assumed that the modem should sync with the DSLAM port setting, which according to a check by Covad just the other day was 1.5/384... |
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Doctor Olds
I Need A Remedy For What's Ailing Me.
Premium,VIP
join:2001-04-19
1970 442 W30
clubs: | reply to bk_856er
That's a bad sign. It should sync at the same rate as your other Modem. If you plug the other Modem back in, do you regain the 1.5 Sync Rate? |
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bk_856er
join:2007-06-08
Palo Alto, CA
| reply to Doctor Olds
I received the Innoband 8860-C1 today and just set it up. The first impression is good and there were no glitches integrating it into my network. However, for some reason the modem is reporting 1.0/384 instead of my usual 1.5/384, with corresponding lower speed tests. Downstream attenuation is down (56dB) and downstream margin is currently 9dB. I'll update again with more details after I get some additional experience with the unit....
Bob |
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Doctor Olds
I Need A Remedy For What's Ailing Me.
Premium,VIP
join:2001-04-19
1970 442 W30
clubs: | reply to bk_856er
Sounds interesting. Please update us when you get the chance. |
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bk_856er
join:2007-06-08
Palo Alto, CA | reply to bk_856er
Pulled the trigger today on a Covad-approved Innoband ADSL2/2+ VOA Firewall Gateway 8860-C1. Looks like a nice unit that'll cover my router needs. I'll post up after I put it through its paces.
Bob |
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bk_856er
join:2007-06-08
Palo Alto, CA
| reply to bk_856er
So far, so good with the GDMT mode....
I'm thinking of experimenting with a different modem than the P-660R-ELNK that I'm using now, and possibly "upgrading" to something else for maximum robustness. I already have a good router/gateway, so my needs are simple bridge mode, and I have enough know-how alter the settings.
Is there a superior modem that'll play nicely with the ELNK LPV service?
Bob |
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