"Bandwidth request failed" error in event log for ZyXel Prestige 944s (cable modem).

I see your modem interconnects to an IP backbone network through the HFC network using the MCNS protocol.    Did the modem ever work?  My guess is that it never worked.  Am I correct?

To elaborate, I am a Road Runner service tech.  (I do appreciate your refusal to help hack a modem. <g>)  The modem does work, until the "Bandwidth request failed" message, when the customer's network loses Internet access until "TFTP completed".    The forward path (downstream) level should be in the range -19dB to +19dB, and reads -0.7dB at the moment.  The upstream can range as high as 61dB and currently reads 45dB.

We use the ZyXel modems for static IP accounts, and Motorola Surfboards for dynamics.  (Ambits for wireless, but we're changing to Netgear for wireless installs.)  I was hoping the error message would ring a bell with someone; kind of point me in the right direction.  We're working with ZyXel now to find a fix for this, but the people I've spoken with so far don't have information on the exact meanings of the sometimes cryptic entries in the event logs.

I would, however, be interested in knowing what other modems you've found that don't work in YOUR system.  You know, head off any problems before their dropped in OUR laps. :-)

-19dB to +19dB???  Not -15 to +15.  The upstream beyond 54 Decibels is seen as a screaming modem on the CMTS.  I could tell you that the white 3Com Docsis modems did not work in our system.  Also the Ericcson, modems have been having issues as well.  I believe the issues would be related to the IOS of your routers or even somewhere with the modem itself.  As for other modems which have been removed from our system recently are the Motorola SB 4200s I believe these were recalled.  At least that is the rumor...

BTW, I have installed Road Runner in the Chicago area at one point.  Most of my installs were done for @home systems.  Some even for Charter.  I was a contractor with what used to be the "premium" computer and modem side installation contractors.

So this modem is having issues at one location or all locations?  If it were one location I would suspect an issue with drops and wiring.  If it is everywhere, I would reject the modems.

Who handles the provisioning on your system?  Are you using CORE or some other provisioning system?

http://www.zyxel.com/support/forum_int.php
I guess you have a login and can post here?

http://www.zygate.com.tw/support/documentation/users_guide/UG-P944S_v3_51.PDF
I don't make this stuff up, this is from ZyXel.
Receive Input level -15 dBmV + 15 dBmV
Transmission Power +8 ~ + 55 dBmV (16 QAM)  +8 ~ + 58 dBmV (QPSK)

"I see your modem interconnects to an IP backbone network through the HFC network using the MCNS protocol. "  You just happened to notice that, huh? :-)

Seriously though, while that is a cool-sounding quote from askey.com (http://www.askey.com/html/docsis_voip.html), I don't see what bearing it has on this issue.

"interconnects to an IP backbone network" -- kind of necessary for Internet access
"through the HFC network" -- Hybrid Fiber-Coax....well, it is a cable modem after all
"using the MCNS protocol" -- as opposed to IEEE 802.14?  Both are DOCSIS compliant.

The modem's levels are (as stated) well within range.  (The document you reference from zygate.com IS over a year old.  I believe the operating range has been adjusted since then, but since we're sitting at 0 to -1 dB, I don't think the outer limits have a lot to do with what's going on.)

Several modems have displayed the same issue, in very widely displaced locations.  Different nodes in different hubs in different cities.  We've tried the latest firmware upgrade, no good.  

Nothing springs immediately to mind as far as common factors between the modems.  Most ZyXels are operating without a problem.  Which leads me to rule out something as wide-ranging as "provisioning" or "IOS".

I think the key is going to lie in figuring out what the error message means.  So if ANYONE has ANY idea what "Bandwidth request failed" means, I would love to hear it!  It's worth 250 points to you.

pbessman, thanks for all your input so far.  Any other ideas, I'm all ears.

Beau.

Can you log into your CMTSs through Telnet?  You might see something with the upstream signal.  Remember, the modem has to broadcast as well.  Many filed techs ignore the fact that while they are above the -15 range, (by the way if you have "new" information as to the acceptable range of a modem I would be curious to see the documentation.) they have attenuated their lines with splitters killing the return path.  What are you using for your CMTS?  Are you using Cisco Ubrs or some other brand?

What is with the users being able to TFTP configurations to these modems?  Is there anything you can do to lock that down from your end?  Is it possible there is a configuration file that is not compatible with your service offerings?

"Bandwidth request failed" would appear to me that the configuration file of the modem is not compatible with your CMTS systems configured parameters.

I can understand that you are frustrated, while I am trying to help you mockery is not appreciated.  I will continue to try and find related items to see if they are angles you have covered or not.  If they are; a simple, been there done that would help.  I only covered those topics as protocols can be everything.

"It's easy to see the hot rod appeal of tinkering with one's cable modem to tap into ridiculously high data speeds, and uncapping has become a popular exercise in the bandwidth-hungry "warez" and movie-trading underground. Today, the most common target is Motorola's popular Surfboard line of cable modems. Hackers generate a replacement configuration file for the modem that omits the capacity limits installed by the service provider. They then trick the modem into accepting the bogus file. "
http://www.securityfocus.com/news/394


<<<isrcip3bw3>>>  Is this designating a 3megabit bandwidth on your system?  Looking at some of the modem hacks from an academic viewpoint it would seem that this is the case.

Do all of your failed modems share this same config file?  It appears that as soon as the config is able to start it is crashed.  I am sure you are aware of that but your TFTP server may be something to look at.  I know we have various TFTP files for our system and they are specific to the brand and model of cable modem.  This occurs under the provisioning phase in our system and once a modem has block synch we know what modem the customer has and what level of service it has been propvisioned to receive.

I can't help but to grasp at straws here if the manufacturer is unable to decipher their internal messages for us.

"Mockery" sounds a bit strong... my original intention was levity.  I apologize if you took offense.  (Not everyone's humor is the same.)  That particular bit of alphabet soup just seemed to be begging for a cool-down.  (It does seem to have been quoted verbatim from an advertisement for another brand of cable modem.)

"Many filed techs ignore the fact that while they are above the -15 range, ... they have attenuated their lines with splitters killing the return path."
The return path is not dead.  The modem is transmitting at an upstream level of 45dB.

The config file is a standard in our system, used by other modems that don't have problems.  "ip3bw3" indicates an allotment of 3 IP addresses and a bandwidth of 1.5M down, 768k up (the bw3 is arbitrary, we have several tiers available for commercial customers.)

"It appears that as soon as the config is able to start it is crashed."

07/24/2003 20:27:36 = "Bandwidth request failed"
07/24/2003 19:42:21 = "TFTP completed"

The times don't indicate that.  They indicate that "TFTP completed", and some time later (about 45 minutes in this case) the "Bandwidth request failed error" popped up.

"I can't help but to grasp at straws here if the manufacturer is unable to decipher their internal messages for us."
That's about where I ended up.

FWIW, I have been an Installer, Lead Installer and Service Technician (node to TV) for 5 years combined.  I was among the first four technicians placed in the Road Runner department two years ago.  We established the installation and service procedures currently used in our system.  I still run service calls in the field, and I still cover everything from the customer's premise to the headend.  I understand the RF side.  I have a certain familiarity with the headend configuration.  What you've posted has not been very helpful.  In fact, if you'll pardon a certain amount of affrontery, some of it sounded like self-aggrandizing drivel.  I don't know what kind of response you expected for "seeing that my modem interconnects with an IP backbone network" etc., but I'm not looking for a theoretical discussion of connection protocols.  I posted a specific problem and you've hit everywhere around it.  I appreciate the time you took (I have seen some of your other responses help other people), and I wish you well.

Thanks again!