Random disconnections from a Terayon TJ715x cable modem?

On 09/29/2008 04:08 PM, Ant sent:

Hello:

Can you monitor your cable modem's receive power level and receive signal-to-noise ratio for awhile? Also, just after you've received a disconnect would be good too.

Before you monitor those, perhaps you could tell us what those instantaneous values are now.

Let us know what you find.

Best wishes to you.

If you have Perl, I have a script that can read out the web pages on your TJ715X - let me know where to email it if you like. If you don't already have the password, it's: icu4at!

http://192.168.100.1/mainPagehttp://192.168.100.1/diagnostics_page.html

RF Parameters Parameter Value Units Tx Power 44.2 dBmV Rx Power -1.9 dBmV Downstream SNR 33.4 dB Downstream MER 32.4 dB Tx Frequency 33000000 Hz Rx Frequency 705000000 Hz

Does that looks OK? I can't check it during the quick disconnections since I can't even connect to the cable modem and even if I could, it goes too fast. I will check again right after disconnections if I am at the computer and noticed it. It is hours ago for the last one overnight, so I will have to wait for the daytime one.

Sure, I have Linux. Can you please kindly post it in

On 09/30/2008 07:47 AM, Ant sent:

Snip, snip...

Initially, I wished to know if your cable modem was running on the ragged edge. However, this does not appear to be the case. When you think about, try looking at these levels again to see if any significant deviance shows up. Although the cable modem hasn't been entirely eliminated from the equation, I would look elsewhere, for now.

My own numbers are -6.3 dBmV & 34.1 dB SNR (downstream) this morning.

For a short time, could you experimentally bypass your router, such that your Linux system's NIC is directly connected to your Terayon cable modem?

Do any of your system logs have anything interesting? dmesg? Are you using the USB port on your modem, or the RJ45 Ethernet connection?

You haven't /yet/ eliminated your cable modem, nor has your ISP's outside plant been ruled out. But hopefully, you can continue to divide and conquer.

I can try that, but I will need to secure my box since my router protects my computer and I will have to rewire my ethernet cat5 cables.

No, like I said my cable modem disconnects my LAN. I lose connections on all computers. My router is fine (no disconnections from pinging

OK.

I think I had a disconnection an hour ago or so, but it might be too late: Tx Power 44.7 dBmV Rx Power -2.0 dBmV Downstream SNR 33.5 dB Downstream MER 32.6 dB Tx Frequency 33000000 Hz Rx Frequency 705000000 Hz

You don't know that from pinging your router - just because you can talk to the router, doesn't mean it's passing data. You haven't done anything to isolate it until you remove the router from the equation as

PS: What kind of router is it ?

On 09/30/2008 10:29 AM, Ant sent:

To a larger extent than a Windows system, your Linux system is best situated to endure an attack without much work on your part. If you are of the belief that your cable modem is failing (not a bad guess) then consider the following:

If you are leasing from your provider, maybe you could save the price of an on-site call by going to their office for a swap of the cable modem.

If you own your cable modem, a replacement can be had for less than $100 or you can ask your service provider for one at about $3 per month.

Netgear RT311 router.

Thanks. For some reason, I used to get charged for three bucks a month for leasing the cable modem before Adelphia went busted. RoadRunner doesn't charge. If I get exchange it, will I be charged again?

If you bought it, you should be able to just put it away and ask for new one (most likely refurbished) from RR since you're entitled to one.

No need to give them the old one.

OK. I hope they can provision in office too.

I got the perl from Bill, made myself a bash script, and they worked for a few minutes, but it seems like this cable modem didn't like its Web pages (listing all) refreshing every two seconds. Now, I can't connect to 192.168.100.1 (DDoS protection?). :( Does this cable modem have a feature to block refreshes/reloads or something?

I might need to unplug and replug its power after I get home if it still doesn't let me in. I am not sure how I can use this script in a loop to monitor its statistics if it blocks Web connections. :(

My script: $ more loop echo -- >> results.txt echo >> results.txt date date >> results.txt perl -x ~/bin/TJ715.pl >> results.txt ./loop

Copy of Bill's perl script:

Strange. I haven't rebooted the cable modem and still cannot connect to

I take that back (spoke too soon). At about 11:06 AM PDT, I got disconnected. :P I guess I will unplug and replug it to be able to access the cable modem later tonight or whenever so I can use the Perl script (if it lets me refresh/reload every few seconds). [grumbles]

I wished there was a way to reboot the cable modem remotely like my router.

On 10/01/2008 11:43 AM, Ant sent:

Hello Ant:

What *does* happen if you try to connect to 192.168.100.1 through your computer's browser?

Pete

If you mean a Web browser, then it just times out and say it didn't connect like as if a Web site/server was down (e.g., "Alert!: Unable to connect to remote host."). I tried it with two different computers (XP Pro. SP3 and Linux/Debian) on LAN last night too. I can ping it and it responds just fine.

I am pretty sure a reboot will fix it (have seen it do this before with manual refreshes/reloads). I just can't do it now since I am near it to unplug and replug the power, and there is no way to reboot it remotely like my Netgear RT311 router. ;)

Yep, reboots fixed the problem. I reran the script to check and log all of the statistics every two seconds and my cable modem's 192.168.100.1 stopped responding to my connection after 37 seconds (check every two seconds).

I made the script to check every one minute (actually 58 seconds since there are two seconds gap). That seems to be working after 15 minutes so far. I hope one minute is enough to catch the disconnections. I probably won't get another disconnection for another 12 hours or so.