bk_856er
join:2007-06-08
Palo Alto, CA
| OK stats, but frequent loss of sync Hi,
Good stable line for a few years until 2-3 months ago. I compared my stats from two years ago and nothing has really changed, and in fact the downstream noise margin has improved. Now getting very frequent loss of sync usually requiring modem power-cycle to restore (many times a day). No chnages to inside wiring.
Can changing to GDMT mode make things more stable?
Is the "other" Earthlink Zyxel ADSL2+ modem (P660R-D1) more stable with a marginal line like mine?
Here are the current stats:
Earthlink ISP (LPV)
Telesurfer 1.5/384
2005 Zyxel P660R-ELNK stats from NID today:
noise margin upstream: 25 db
output power downstream: 16 db
attenuation upstream: 38 db
noise margin downstream: 14-17 db (range of multiple tests)
output power upstream: 11 db
attenuation downstream: 62 db
CPU Load: 0.26%
Upstream Speed: 383 kbps
Downstream Speed: 1532 kbps
Zyxel normally in bridge mode.
14k feet to CO according to ATT info.
Speed tests from SpeakEasy servers today:
Download Speed: 1295 kbps (161.9 KB/sec transfer rate)
Upload Speed: 319 kbps (39.9 KB/sec transfer rate)
This was my original success story a few years ago (post now too old to add to):
»[General] interpreting Zyxel diagnostic numbers | |
|
 |
 | bk_856er
join:2007-06-08
Palo Alto, CA
| Re: OK stats, but frequent loss of sync I did the AM radio retest and I found one obnoxious dimmer about 15ft away from the networking gear and a few noisy Netgear power transformfer bricks relatively close to the modem. An HP laser printer in its idle state was the worst AM radio offender of all, and this device is also near the networking equipment (12 inches). Additionally, I had an in-use 100ft ethernet cable coiled up and stashed behind the printer. Perhaps the coiled cable can collect and introduce noise into the system? I'll collect some more modem data and see if anything is improved.
Question. In cases where you need to live with a suspect RFI emitter, are there any strategies to minimize the effects, such as moving it further away, shielding, etc?
With respect to the 660 zyxel modems, I noticed that my ELNK model has the original ~2005 firmware and I can't find an update. The retail zyxel model has a series of firmware reversions with the most recent one just a month old. Maybe some of those are performance improvements? Looks like I can buy a D1 version for $50 if I want to experiment (rather not spend the cash if I don't need to!).
Bob | |
|
| | |
| | | bk_856er
join:2007-06-08
Palo Alto, CA
| Re: OK stats, but frequent loss of sync Not much progress, I'm afraid. I rearranged the equipment and re-routed + shortened some wiring, but lost sync a few times in the next hour. Tonight I will collect downstream noise margin data as I cycle the identified RFI generators. I need some data to correlate with the behavior.
Is the actual modem the most susceptible to RFI, or the incoming phone line within the residence? My AM radio testing showed that obstructions (boxes, shelves, etc.) blocked RFI pretty effectively. I needed to move some large boxes to access the incoming line and splitter, which could have compounded my issue by exposing everything since I have not yet replaced the boxes to their former locations. ALL my own wiring is good quality twisted-pair stuff, but not the shielded type. It's only about 8ft from the exterior NID to the splitter and modem. Maybe more clever and less exposed routing will help. Feels like a wild goose chase!
A couple of years ago one of the Covad techs here suggested changing to GDMT mode. Why? I have the procedure for making the change via telnet, but what if it does not work out? How do I change back - presumably to Multi-Mode?
Bob | |
|
| | | | 
Doctor Olds
I Need A Remedy For What's Ailing Me.
Premium,VIP
join:2001-04-19
1970 442 W30
clubs: | Re: OK stats, but frequent loss of sync Yes, you can try G.DMT Mode or even ANSI T1.413 Mode as those are the original DSL Standards before ADSL2 and ADSL2+. | |
|
| | | | | bk_856er
join:2007-06-08
Palo Alto, CA
| Re: OK stats, but frequent loss of sync And both of those alternatives (G.DMT and ANSI T1.413) are compatible with Earthlink LPV service?
Is is safe to assume that "dropping down" in the standards is OK because I'm only at 1.5/384?
(BTW, thanks for the ongoing input!)
Bob | |
|
| | | | | |
Doctor Olds
I Need A Remedy For What's Ailing Me.
Premium,VIP
join:2001-04-19
1970 442 W30
clubs:
| Re: OK stats, but frequent loss of sync Correct. ADSL2+ Modems are backwards compatible to the earlier ADSL Standards.
| |
|
| | | | | | | bk_856er
join:2007-06-08
Palo Alto, CA
| Re: OK stats, but frequent loss of sync I invested about 3hrs tonight testing the modem noise margins under various conditions. I unplugged virtually everything in the (small) house, monitored the readings for a good bit, and then one by one added things back in. The bottom line is that nothing really made a consistent difference. I did learn that over a longer space of time my downstream noise margins can range between 7db and 16db, and at the low end sync gets iffy. Things are happy at 13db.
On a few occasions the downstream noise margins slowly decreased from 15db to 7db over about 15 minutes with eventual sync loss. Sort of a death spiral. When sync returned automatically a short time later the noise readings were back to normal.
During some periods of consistently low noise margin readings, if I "reset ADSL" with the web interface the noise margins returned to good levels with the new sync. It seems as if some connections are good and some are poor and are doomed.
At one point I thought that things might be correlated with the refrigerator running, but that too proved to be inconsistent. Nonetheless, I think I might benefit from a UPS with a line power conditioner.
I can't find a definitive "in-house" RFI cause for my occasional sync loss, but now I have a better feel for the behavior and I can rule out a bunch of stuff. On the upside, my installation is now very professional looking and strictly according to best practices! That alone might give me the slight edge that I need to stabilize a marginal line.
I tested out the zyxel telnet features. The mode change to GDMT is not a menu item, but is invoked with an undocumented "wan adsl opencmd gdmt" command according to Covad. Anyone know the command to restore ADSL2+ mode? I'm going to hold off on changing the mode until I know how to get back to where I am now.
Bob | |
|
| | | | | | | |
Doctor Olds
I Need A Remedy For What's Ailing Me.
Premium,VIP
join:2001-04-19
1970 442 W30
clubs:
3 edits | Re: OK stats, but frequent loss of sync A reset should bring the unit back as delivered. 
»Re: Zyxel P660R-ELNK stability issues...
said by chrp2007  :try this - thanks to e_dub at covad.direct forumopen your command prompt and type: telnet 192.168.1.1 the password should be: 1234 you will see a list of menus, type 24 and hit enter another list of menus will appear, type 8 and hit enter you see a flashing cursor at the bottom of the screen; here you will enter: wan adsl opencmd gdmt hit enter. (once you hit enter your modem will lose sync because of the change. it will regain sync.) you will be taken back to the flashing cursor. type exit to back out, your now done. just exit out of all the menu thus exiting telnet. I also added this info to the Earthlink FAQ:
»EarthLink DSL FAQ »How to set the P660R series to use the G.DMT DSL Standard only? | |
|
| | | | | | | | | bk_856er
join:2007-06-08
Palo Alto, CA | Re: OK stats, but frequent loss of sync Nice work!
Wow, the link mentioning the "ring loop imbalance" with gradually decreasing downstream S/N readings sounds very similar to my death spiral.
I'll try the GDMT tomorrow.
Bob | |
|
| | | | | | | | | DSum
join:2009-07-01
Los Angeles, CA
| Re: OK stats, but frequent loss of sync Hi,
I don't have a solution for bk_856er, but I have similar problems.
I'm in West Los Angeles, CA, three blocks from the CO. No problems for years with a Zyxel Prestige 645M (yes, a 645M, not some flavor of 660 or a 645-UHP) with Covad/Verizon.
Then two weeks ago I started losing sync randomly, sometimes for a few minutes, sometimes for half a day. No sync for most of Friday, then it worked all weekend when I used it heavily, but then not at all Monday, 50-50 on Tuesday.
I don't want to "hijack" this thread with my problems (I'll start a new thread if needed), but Bob may not be alone and I'm curious to see what eventually works for you.
Dale | |
|
| | | | | | | | |
Doctor Olds
I Need A Remedy For What's Ailing Me.
Premium,VIP
join:2001-04-19
1970 442 W30
clubs:
| Re: OK stats, but frequent loss of sync Your Modem is a Bridge and you have to use Telnet to obtain the DSL Stats.
»EarthLink DSL FAQ »How do I access my Earthlink/Covad ZyXEL P645 modem (Bridge Model, not UHP)?
The commands to run in Telnet are in bold in the example below.
quote:
ChangeMe> wan adsl chandata
near-end interleaved channel bit rate: 0 kbps
near-end fast channel bit rate: 3008 kbps
far-end interleaved channel bit rate: 0 kbps
far-end fast channel bit rate: 384 kbps
ChangeMe> wan adsl linedata near
relative capacity occupation: 88%
noise margin downstream: 6.5 db
output power upstream: 12.0 dbm
attenuation downstream: 47.5 db
ChangeMe> wan adsl linedata far
relative capacity occupation: 59%
noise margin upstream: 16.0 db
output power downstream: 20.0 dbm
attenuation upstream: 31.5 db
--
What’s the point of owning a supercar if you can’t scare yourself stupid from time to time? | |
|
| | | | | | | | | bk_856er
join:2007-06-08
Palo Alto, CA
| Re: OK stats, but frequent loss of sync I contacted Zyxel and obtained the last firmware that Earthlink provided to them for the -ELNK flavor modem. After installing the update (twice) the version reported is the same as before. Bin file was "P660R-ELNK-340AHC3D0." I need to contact Earthlink for something more recent if it's available.
Next I put the modem into GDMT mode. The downstream S/N and attenuation improved immediately! The latest stats are below. Time will tell if the connection is more stable, but I like what I see so far!!
System Name:
ZyNOS F/W Version: V3.40(AHC.0) | 11/16/2005
DSL FW Version:TI AR7 05.00.03.e6
Standard:Multi-Mode (does not show G.DMT mode??)
noise margin upstream: 18 db
output power downstream: 16 db
attenuation upstream: 31 db
noise margin downstream: 19 db (highest ever!)
output power upstream: 12 db
attenuation downstream: 60 db (lowest ever!)
SpeakEasy speed test performed today after the changes:
Download Speed: 1288 kbps (161 KB/sec transfer rate)
Upload Speed: 322 kbps (40.3 KB/sec transfer rate)
Bob | |
|
| | | | | | | | | |
| | | | | | | | | bk_856er
join:2007-06-08
Palo Alto, CA
| Re: OK stats, but frequent loss of sync That's too funny. I just spent 20min with Earthlink support and they were adamant that no firmware update exists, although they were eager to sell me a new modem. I can't get past the password request for that link using my Earthlink info. Anyone know what filename resides there?
Bob | |
|
| | | | | | | | |
Doctor Olds
I Need A Remedy For What's Ailing Me.
Premium,VIP
join:2001-04-19
1970 442 W30
clubs:
| Re: OK stats, but frequent loss of sync said by bk_856er : I can't get past the password request for that link using my Earthlink info. Anyone know what filename resides there? I can't either. Don't know why and I tried all 8 of my accounts credentials starting with the main account username/password. Strange. Also don't know the filename.
--
What’s the point of owning a supercar if you can’t scare yourself stupid from time to time? | |
|
| | | | | | | | | bk_856er
join:2007-06-08
Palo Alto, CA
| Re: OK stats, but frequent loss of sync I chatted with support again and tried to get access to that specific page. Waste of time. They insisted that modem firmware is "upgraded on the server end when the modem powers on" and then finally that only their "engineers" can access that page. None of their info was accurate in the least, so I don't believe any of it. That link is taunting me!
At any rate, I now seem to have the original firmware file from Zyxel, so maybe I can risk trying the retail D1 firmware and then downgrade if I run into trouble. Then again I might savor my new connection stability for a while longer. I've bricked a device or two in my time with botched firmware updates...
Bob | |
|
| | | | | | | | | bk_856er
join:2007-06-08
Palo Alto, CA
| Re: OK stats, but frequent loss of sync 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 | |
|
| | | | | | | | | bk_856er
join:2007-06-08
Palo Alto, CA | Re: OK stats, but frequent loss of sync 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 | |
|
| | | | | | | | |
Doctor Olds
I Need A Remedy For What's Ailing Me.
Premium,VIP
join:2001-04-19
1970 442 W30
clubs: | Re: OK stats, but frequent loss of sync Sounds interesting. Please update us when you get the chance. | |
|
| | | | | | | | | bk_856er
join:2007-06-08
Palo Alto, CA
| Re: OK stats, but frequent loss of sync 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 | |
|
| | | | | | | | |
Doctor Olds
I Need A Remedy For What's Ailing Me.
Premium,VIP
join:2001-04-19
1970 442 W30
clubs: | Re: OK stats, but frequent loss of sync 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? | |
|
| | | | | | | | | bk_856er
join:2007-06-08
Palo Alto, CA | Re: OK stats, but frequent loss of sync 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... | |
|
| | | | | | | | | |
| | | | | | | | | bk_856er
join:2007-06-08
Palo Alto, CA | Re: OK stats, but frequent loss of sync 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! | |
|
| | | | | | | | | bk_856er
join:2007-06-08
Palo Alto, CA
| Re: OK stats, but frequent loss of sync 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 | |
|
| | | | | | | | | |
| | | | | | | | | bk_856er
join:2007-06-08
Palo Alto, CA
| 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) | |
|
| | | | | | | | | 
e_dub
franknbeans
Premium,VIP
join:2001-08-12
kickin ass
| Re: OK stats, but frequent loss of sync 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. | |
|
| | | | | | | | | bk_856er
join:2007-06-08
Palo Alto, CA | Re: OK stats, but frequent loss of sync 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 | |
|
| | | | | | | | | bk_856er
join:2007-06-08
Palo Alto, CA
| 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 | |
|
| | | | | | | | |
e_dub
franknbeans
Premium,VIP
join:2001-08-12
kickin ass
| Re: OK stats, but frequent loss of sync 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. | |
|
| | | | | | | | | |
| | | | | | | | | bk_856er
join:2007-06-08
Palo Alto, CA
| Re: OK stats, but frequent loss of sync 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 | |
|
| | | | | | | | |
e_dub
franknbeans
Premium,VIP
join:2001-08-12
kickin ass
| Re: OK stats, but frequent loss of sync 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. | |
|
| | | | | | | | | 
DrStrange
Technically feasible
Premium
join:2001-07-23
West Hartford, CT | 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. | |
|
bk_856er
join:2007-06-08
Palo Alto, CA
| 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 | |
|
|
|
|
·
·