Film-Tech Forum ARCHIVE: Cable modem issue?

This is topic Cable modem issue? in forum Film-Yak at Film-Tech Forum ARCHIVE.

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Posted by Joe Redifer (Member # 3) on 08-08-2011, 07:27 PM:

Whenever I try to upload a file to my FTP, the cable modem starts out blazingly fast, slows down and eventually stops and reboots itself. I can upload videos to Youtube all day with any issues, though it is likely that it has rebooted itself during this once or twice.

Is the cable modem likely the issue here? If so, what are some recommended cable modems?

Posted by Greg Routenburg (Member # 1742) on 08-08-2011, 07:47 PM:

It could be traffic shaping by your ISP as well. If your connection is stable and fast for all other applications then I wouldn't suspect your modem. I'm using a Motorolla cable modem and have no complaints.

Posted by Joe Redifer (Member # 3) on 08-09-2011, 12:27 AM:

Why would this only happen when I am uploading to a particular FTP? Would my ISP be seeing this and saying "Oh NO NO NO!" and causing the reset? For what purpose?

Posted by Ron Lacheur (Member # 1126) on 08-09-2011, 12:30 AM:

The resetting sounds like the modem is overheating. Is there anything sitting on top of it?

Failing that, it is a faulty modem.
ISP throttling wouldn't cause the modem to reset like that.

Posted by Joe Redifer (Member # 3) on 08-09-2011, 01:36 AM:

Nothing on top of it, but it is old. The brand is Arris. Should I be proud of something from Arris in my house?

Posted by Rick Raskin (Member # 1561) on 08-09-2011, 06:24 AM:

It could very well be traffic shaping by the ISP and resulting buffer over-runs in the modem or router. Are you using a router before the modem? Try connecting directly to the cable modem and see what happens. You may have to do an ipconfig/release followed by ipconfig/restore to clear the IP address at the ISP and get a new one. I don't know the comparable command in Mac land.

Posted by Jeff Kane (Member # 6372) on 08-09-2011, 11:15 AM:

Timing out and rebooting? I'm thinking failure/reboot caused by continuous transmission and/or marginal signal levels. I had an old Motorola that would overheat and quit sending data (although it didn't spontaneously reboot). I'd have to unplug it and plug it back in to get it to work again.

Even if the cable co were throttling, the modem shouldn't reboot. Do you own the modem? If so, get one at Best Buy so you can take it back if that's not the issue. If not? Call 'em and make 'em replace it!

Posted by Randy Stankey (Member # 64) on 08-09-2011, 11:31 AM:

What does your modem's status page (192.168.1.1) say? Can you get to the transceiver status readout?

While it might not solve the problem, plugging the modem directly into your network interface, bypassing your inside wiring, could give you some insight to your modem's performance.

If you take a reading while plugged in normally then compare the modem's power level, attenuation and margin when it's plugged directly to the interface, it might give you some insight.

I do not use the DSL filters supplied by my ISP (Verizon) but, instead, use a line splitter. The line comes into the house then goes into the splitter. My modem is connected to the "Data" branch of the splitter and all of the phone extensions in my house star off from the "Voice" branch using a punchdown block.

Doing that made a big difference in performance.

I also agree that your ISP might be shaping FTP traffic. I have had a couple of notices from my ISP regarding changes to the way they allow FTP traffic through their network, citing security concerns, but that has to do, mostly, with how you can access your personal web space and things like that. However, I wouldn't put it past them to also do other things behind the customer's back.

I have had Verizon make changes to my modem's firmware without telling me first. This happened on two occasions. Both times, I found my settings all defaulted and my password changed. Only after calling Verizon and hollering at them did they admit that they accessed my modem.

Now, if they had told me about it first I wouldn't have been so pissed off.

It is worthwhile to check to see if your ISP has changed firmware or settings in your modem without telling you first.

Posted by Rick Raskin (Member # 1561) on 08-09-2011, 02:02 PM:

quote: Randy Stankey
I do not use the DSL filters supplied by my ISP (Verizon) but, instead, use a line splitter. The line comes into the house then goes into the splitter. My modem is connected to the "Data" branch of the splitter and all of the phone extensions in my house star off from the "Voice" branch using a punchdown block.

You should install a DSL filter on the "Voice" side of the splitter between the splitter and the punchdown block. This will keep on-hook & off-hook signals from interfering with the data path. The "Data" branch doesn't need a filter.

Posted by Randy Stankey (Member # 64) on 08-09-2011, 05:36 PM:

This is similar to the device I use:
http://www.wilcominc.com/Item.cfm?ProdID=35

...except that mine does not have the RJ-11 jacks on it. Only the screw terminals.

I did not think that you needed a DSL filter once the splitter is in place but I can sort of understand what you are saying. I will certainly look into it and see if going on/off-hook has effects on data transfer.

Posted by Joe Redifer (Member # 3) on 08-09-2011, 06:37 PM:

I had my ISP replace the modem and all seems to work fine now.

Posted by Rick Raskin (Member # 1561) on 08-10-2011, 06:10 AM:

The filter is included in the device you are using. I thought you were describing a passive line splitter; the kind that allows two connections to one line.