Topic '[Connectivity] Purchase your own modem = Comcast interfering wit' in forum 'Comcast HSI' - dslreports.com

Re: [Connectivity] Purchase your own modem = Comcast interfering

Sun, 03 Feb 2013 22:06:44 EDT

KitFox posted : The custom firmware on the routers will probably have the SPI (Stateful Packet Inspection) firewall activated by default. It allows things like Javascript and specific web sites and such to be blocked. Unfortunately it also demolishes the CPU of all but the most hardy of routers. I have a router with a very hefty CPU. Routing gigabit internally is a fraction of a percent of the CPU normally. The firewall spikes the CPU and network handling and reduces the usable bandwidth tremendously.

Try turning off the firewall feature of the router and see if that helps.

Re: [Connectivity] Purchase your own modem = Comcast interfering

Thu, 31 Jan 2013 20:42:46 EDT

MisterP posted : OR, you could get a 5341J Zoom modem, better modem (CableLabs said so, so :p ), better warranty, 8 channel down for 70 bucks and stick it to The Man/The System (The Motorola man that is)

Come to the dark side lol

This comes from a former 6121 owner who got fed up with the T3s and etc issues and was especially glad I switched when Motorola's firmware "solution" to the T3/T4 issue was not to actually address/resolve it, but just to lock out the offending channel, thus dropping you to two upstreams. Hooray for complacency and band-aids.

Re: [Connectivity] Purchase your own modem = Comcast interfering

Mon, 28 Jan 2013 18:14:56 EDT

fatmanskinny posted : Ha. I left Comcast Xfinity Voice for Vonage. $9.99 a month + taxes. I don't even use my home phone that much to justify $47+ a month for Comcast Phone.
--
A citizen of The United States of Amnesia. How quickly we forget.

Re: [Connectivity] Purchase your own modem = Comcast interfering

Mon, 28 Jan 2013 13:31:53 EDT

YukonHawk posted : So I called Comcast over the weekend to see if I could purchase my own modem...they said sure! But then I felt the vice tighten around my plums :o when the rep said," You will then need to pay a monthly charge for the EMTA" that we get for free now for the VoIP. I said thanks but no thanks and hung up! Ya can't win!!! :huh:
(I have a Cisco 3008 for the internet and an Arris EMTA for the VoIP)

Re: [Connectivity] Purchase your own modem = Comcast interfering

Mon, 28 Jan 2013 13:02:40 EDT

fatmanskinny posted : Thanks. I just headed to Best Buy and picked one up. In addition to updating the firmware on my routers and killing the DHCP server in my Vonage box (it sits behind the router, not before it), I will have Comcast add the new modem later today and see what happens.

I will return the 6121 back. Thanks again.

EDIT: So I connected the 6141 and seem to be rocking and rolling. However, I discovered another issue. I am using 2 Linksys 54GLs with open source software. They have 10/100 port connections. When I connected my modem directly to my laptop, it switched to 1000 throughput.

The bottleneck is in the routers. I have to get a newer router in the near future as I am losing about 300% of my available download bandwidth when connecting through the Linksys routers. I pull 35/6 directly connected to the modem and 7-8/5 through the routers.

I will probably keep the Linksys as a separate wireless LAN for visitors and work-related projects and use the new wireless LAN for personal surfing and my Vonage service.

Thanks everyone for your assistance.

--
A citizen of The United States of Amnesia. How quickly we forget.

Re: [Connectivity] Purchase your own modem = Comcast interfering

Sun, 27 Jan 2013 08:52:29 EDT

andyross posted : The 6180 has been out for a long time and was one of the first 8x4 modems, but I'm not certain if Comcast ever supported it.

Re: [Connectivity] Purchase your own modem = Comcast interfering

Sat, 26 Jan 2013 18:23:35 EDT

IowaCowboy posted : I was at Best Buy today and they now have the Motorola 6141 for the same price they were selling the 6121 for (currently $99.99 at the Holyoke Mall BB).

I would return the 6121 and get the 6141 as that supports 8x4 channel bonding.

The Best Buy 6141 comes in a white case but with the same design as the 6121 (except the case is white instead of black).

Edit: I also found out that there is now the 6180, which is also 8x4 channel bonding.

Re: [Connectivity] Purchase your own modem = Comcast interfering

Sat, 26 Jan 2013 09:22:00 EDT

fatmanskinny posted : I am starting to wonder if my routers may be involved. I have two Linksys 54 routers with Tomato running on them and they have 192.168.1.1 and 192.168.2.1 addresses. They are both linked together where the 192.168.2.1 router is wirelessly bridged into the other one.

I was surfing again this AM and the connection locked up. Speeds tests through Chrome came back really low (700k/300k). When I tried to hit the modem, I couldn't reach the page to refresh it. When I tried to hit my routers, they were taking a long time to come up and display. I would think since my wireless routers sit behind my modem, I would be able to hit them regardless of what's going on with Comcast's network. However, I couldn't hit them for some seconds if not about a minute.

I have some more troubleshooting to do and may need to completely dismantle my network and rebuild piece by piece with testing each time for a few days. It can also be the laptop, which is relatively new. I just noticed the firmware for my routers are 3 versions out of date (1.25). I am going to start there.

Any other ideas appreciated.
--
A citizen of The United States of Amnesia. How quickly we forget.

Re: [Connectivity] Purchase your own modem = Comcast interfering

Sat, 26 Jan 2013 08:34:09 EDT

andyross posted : The T4 Timeout issue with the middle channel is a known bug with the Motorola's. It's online, but the status page has that odd Offline message. Personally, I found that doing a power-off reboot seemed to clear up a T4 more reliably than rebooting from the GUI.

Re: [Connectivity] Purchase your own modem = Comcast interfering

Fri, 25 Jan 2013 23:21:25 EDT

NetFixer posted :

said by fatmanskinny:

Funny thing is I just rebooted the modem through the GUI interface and that T4 Timeout error disappeared and the modem is showing as being Operational instead of Offline.

I will continue to monitor it.

That screen that shows the modem as Offline with failed tests seems to be a firmware bug in the SB6121 that sometimes happens when there are problems with getting the upstream bonded channels fast enough to satisfy its timeout algorithms; and a software reboot usually makes it go away.

The couple of times I have seen that, the modem was actually on-line; it was just the display page that had not been updated properly.

FWIW, my SB6121 has been on-line for a month with no problems since the last reboot, and the only times it has ever disconnected was because of Comcast problems, or because I was shuffling equipment around and had to unplug it. Of course, lemons do get out the factory door, so YMMV.
--
A well-regulated militia, being necessary to the security of a free State, the right of the people to keep and bear arms shall not be infringed.

When governments fear people, there is liberty. When the people fear the government, there is tyranny.

Re: [Connectivity] Purchase your own modem = Comcast interfering

Fri, 25 Jan 2013 23:05:59 EDT

fatmanskinny posted : Lol! I left myself wide open for that picture.

Re: [Connectivity] Purchase your own modem = Comcast interfering

Fri, 25 Jan 2013 23:00:41 EDT

fatmanskinny posted : Funny thing is I just rebooted the modem through the GUI interface and that T4 Timeout error disappeared and the modem is showing as being Operational instead of Offline.

I will continue to monitor it.
--
A citizen of The United States of Amnesia. How quickly we forget.

Re: [Connectivity] Purchase your own modem = Comcast interfering

Fri, 25 Jan 2013 20:26:53 EDT

NetFixer posted :

said by fatmanskinny:

The firmware is SB_KOMODO-1.0.6.8-SCM01-NOSH.

That is the latest firmware, so at this point, hopefully your replacement rental modem will arrive soon and you can then find out if the T4 timeouts are because of a defective SB6121, or because of problems in Comcast's infrastructure.
--
A well-regulated militia, being necessary to the security of a free State, the right of the people to keep and bear arms shall not be infringed.

When governments fear people, there is liberty. When the people fear the government, there is tyranny.

Re: [Connectivity] Purchase your own modem = Comcast interfering

Fri, 25 Jan 2013 20:04:40 EDT

fatmanskinny posted : The firmware is SB_KOMODO-1.0.6.8-SCM01-NOSH.

Re: [Connectivity] Purchase your own modem = Comcast interfering

Fri, 25 Jan 2013 19:58:54 EDT

NetFixer posted : Those T4 Timeouts are the problem, but with your signal levels, that should not be happening. Either that specific modem really is defective, or Comcast is having some infrastructure problems. If you look at the Help tab in the modem, what firmware version is installed?

If you have already told Comcast to send you another rental modem, you can check its signal levels and see what it does when it arrives. Personally, I would hold on to the SB6121 until I was sure that the problem was actually the modem (but you don't want to keep it so long that the retailer won't take it back).
--
A well-regulated militia, being necessary to the security of a free State, the right of the people to keep and bear arms shall not be infringed.

When governments fear people, there is liberty. When the people fear the government, there is tyranny.

Re: [Connectivity] Purchase your own modem = Comcast interfering

Fri, 25 Jan 2013 19:43:04 EDT

fatmanskinny posted : Nevermind on this post. See above!

Re: [Connectivity] Purchase your own modem = Comcast interfering

Fri, 25 Jan 2013 19:42:11 EDT

fatmanskinny posted : Status and Signal images attached.

Status_Tab
Signal_Tab

Re: [Connectivity] Purchase your own modem = Comcast interfering

Fri, 25 Jan 2013 19:39:48 EDT

Brendan posted : I have an SB6120, working flawlessly, since I returned the "ordained" modem. This is in Denver, CO.

It's a Conspiracy!

Re: [Connectivity] Purchase your own modem = Comcast interfering

Fri, 25 Jan 2013 19:36:21 EDT

fatmanskinny posted : Nah. I already ordered a new modem from Comcast. I'll consider the $7 rental free as insurance and return the POS Motorola modem.
--
A citizen of The United States of Amnesia. How quickly we forget.

Re: [Connectivity] Purchase your own modem = Comcast interfering

Fri, 25 Jan 2013 19:33:57 EDT

fatmanskinny posted : Yeah, I have to give them the benefit of the doubt. For $7 a month, at least I have the peace of mind that if the modem craps out, I can have them replace it. Since I work from home at times and need to have pretty solid speeds, I can't risk using this modem after today.
--
A citizen of The United States of Amnesia. How quickly we forget.

Re: [Connectivity] Purchase your own modem = Comcast interfering

Fri, 25 Jan 2013 19:33:24 EDT

NetFixer posted :

said by fatmanskinny:

I purchased a new Motorola SB 6121 modem from Walmart and returned Comcast's Voice Modem as I moved to Vonage. I have been having intermittent speed issues throughout the day.

Now, after I called Comcast to send me a new Comcast "ordained" modem because I plan to return this modem to Walmart, the speeds on this modem return back to super fast. Are there any known cases of Comcast jacking with your service, forcing you to switch over? Before this voice modem, I had a Linksys that I purchased and suddenly, the Linksys modem would not connect and Comcast could not see it.

In Comcast's defense, I did Google around about the Motorola SB 6121 and have noticed others having similar issues with other cable providers and Comcast but not everyone was having issues.

Any thoughts?

I swapped my rented SMD3G for an SB6121 that I purchased, and I have had no problems with it whatsoever. SB612x modems before firmware release SB_KOMODO-1.0.6.8-SCM01-NOSH did have problems with rebooting if they lost an upstream channel, but that should no longer be a problem.

The SB612z modems are a bit sensitive about their upstream power levels (they need to be below 50dBmv) and that did make them somewhat unreliable prior to the current firmware release (which Comcast should upload automatically). If you are looking for help (and not just ranting), post some screen shots of your modem's Status and Signal tabs.
--
A well-regulated militia, being necessary to the security of a free State, the right of the people to keep and bear arms shall not be infringed.

When governments fear people, there is liberty. When the people fear the government, there is tyranny.

Re: [Connectivity] Purchase your own modem = Comcast interfering

Fri, 25 Jan 2013 19:28:19 EDT

pflog posted : No way would they do that. It'd come back to bite them big time. I'm 99.99999999% sure this was a coincidence.
--
"I drank what?" -Socrates

[Connectivity] Purchase your own modem = Comcast interfering wit

Fri, 25 Jan 2013 19:16:06 EDT

fatmanskinny posted : I purchased a new Motorola SB 6121 modem from Walmart and returned Comcast's Voice Modem as I moved to Vonage. I have been having intermittent speed issues throughout the day.

Now, after I called Comcast to send me a new Comcast "ordained" modem because I plan to return this modem to Walmart, the speeds on this modem return back to super fast. Are there any known cases of Comcast jacking with your service, forcing you to switch over? Before this voice modem, I had a Linksys that I purchased and suddenly, the Linksys modem would not connect and Comcast could not see it.

In Comcast's defense, I did Google around about the Motorola SB 6121 and have noticed others having similar issues with other cable providers and Comcast but not everyone was having issues.

Any thoughts?
--
A citizen of The United States of Amnesia. How quickly we forget.