Selected ISP Support > Earthlink DSL > OK stats, but frequent loss of sync

reply to bk_856er

Re: OK stats, but frequent loss of sync

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...

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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)

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
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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.

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

reply to e_dub

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.
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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.

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.

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

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.