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CGN3 wired connection dying?

I Plan to Stick Around

I have a CGN3 in bridge mode that's been working fine for a month or two. Then, yesterday, I noticed that the internet was dead and I couldn't access even the modem's statistics page. I unplugged the CGN3, it came back up, and everything was fine again.


For a while. I just noticed that it's happened again. Basically, the wired connection dies - I get no lights whatsoever on the port at my router, it's like there's no cable connected. On the modem, CGN3, the normally blinking light is also solid off. Unplugging/replugging the cable at both ends makes no difference - I have to yank the power and let the modem reboot, and then it works again.


Based on the past 2 times, I'm now assuming only for a while.


Once it's back up, my stats seem fine:


Downstream Overview

Port ID Frequency (MHz) Modulation Signal strength (dBmV) Channel ID Signal noise ratio (dB)
1 663000000 256QAM 0.900 12 38.605
2 591000000 256QAM 0.800 1 38.983
3 597000000 256QAM 1.000 2 38.983
4 603000000 256QAM 0.800 3 38.605
5 609000000 256QAM 0.800 4 38.983
6 615000000 256QAM 1.100 5 38.983
7 621000000 256QAM 0.600 6 38.983
8 633000000 256QAM 0.700 7 37.636
9 639000000 256QAM 0.600 8 38.983
10 645000000 256QAM 0.900 9 38.983
11 651000000 256QAM 0.600 10 38.605
12 657000000 256QAM 0.500 11 38.983
13 669000000 256QAM 0.500 109 38.983
14 675000000 256QAM 0.700 110 38.605
15 681000000 256QAM 0.600 111 38.605
16 687000000 256QAM 0.500 112 38.605
17 693000000 256QAM 1.000 113 38.983
18 699000000 256QAM 0.700 114 38.605
19 705000000 256QAM 1.000 115 38.605
20 711000000 256QAM 1.300 116 38.605
Upstream Overview
Port ID Frequency (MHz) Modulation Signal strength (dBmV) Channel ID BandWidth
1 30596000 ATDMA - 64QAM 43.000 6 6400000
2 23700000 ATDMA - 64QAM 43.000 7 6400000
3 38596000 ATDMA - 64QAM 43.000 5 3200000


But of course the error log seems to be reset by rebooting, so I have no idea what might've happened. No gaming is going on, just general internet usage.


Anyone else have this? Problem, or perhaps a side-effect of work maybe happening in the area (Markham)?




***Edited Labels***


Re: CGN3 wired connection dying?

Hey @etresoft,


Welcome to the Rogers Community Forum!


Thanks for the detailed post. I appreciate the amount of time and effort you've put into troubleshooting your issue.


There isn't any known fault with the Ethernet connection dropping while in bridge mode and you are running the latest firmware available for that model. Out of curiousity, have you tried the same test with bridge mode disabled?


Considering all the steps you've taken in trying to narrow down the problem, I'd suggest swapping out the modem. You can do so at any of our Rogers retail stores. Just ensure that you bring the power adaptor along with the modem and a piece of identification and they'll take of it for you.


Community, feel free to chime in with any input or ideas! I'll also tag a couple of our very knowledgeable Resident Experts, to provide some insight! @gp-se @VivienM @Datalink


Keep us posted!



Re: CGN3 wired connection dying?

Thanks for letting me know the firmware is up-to-date. If I swapped out the modem, I would just get another identical model, right?


I don't know if I'm running the same bridge mode that other people are talking about. I have wireless disabled on the Rogers modem. My old wifi router is running in bridge mode and it is handling the wifi. I have 150/15 service and I actually get 100/15. The Rogers modem can't do wifi that fast. Should it? That is why I have my own wifi router.


I don't see why having that wifi router connected via ethernet would make other ethernet devices have problems. Disconnecting it is not a solution because then I'm paying for 150/15 and getting 50/15. I would rather use my ping script that limits the disconnects to 5 seconds. I suppose I could crank it up to once per second, but it feels wrong to have to do a hack like that just to keep the network up.


I will investigate the modem's bridge mode and maybe swap it if I can't get any improvement. I have to wait for an opportunity to do this kind of work.

Re: CGN3 wired connection dying?

@etresoft something isn't making sense here.  If you have the modem running with the Wifi disabled, that implies that the modem is running in Gateway mode, providing DHCP services to the network.  Your statement indicating that the router is running in Bridge mode implies that it is providing one half of a wifi bridge.  That Wifi Bridge mode in routers is used to span a distance where connection via ethernet is not possible, so, you would normally have the modem running in Gateway mode with its wifi running, providing part one of the Wifi Bridge, the router running in Bridge mode providing the second half of the Wifi Bridge.  You would then connect ethernet devices to the router.  Those devices wouldn't know or care that the connection to the modem is via wifi instead of ethernet, but, they would be located in some part of the home where ethernet cabling back to the modem is not available. 


If you have the modem running in Gateway mode with its Wifi disabled, then you would normally run a follow-on router as a wifi/wired Access Point.  In that mode, the routers DHCP server and firewall would be disabled.  Newer routers have such a mode available and the router connects to the modem via the router's WAN port.  For older routers that don't have that mode, you would disable the DHCP server and firewall and set up the wifi as required.  The router would then be connected to the modem via one of the routers LAN ports.  In that configuration, there is only one DHCP server in the network.  I'm honestly not sure of how your network is running if the router is actually set for Bridge mode.  In theory, there should be one DHCP server on the network which is running in the modem.  If the DHCP server is running in the router as well, then you have a double NAT situation running, which can definitely cause network issues.


Fwiw, if you're running an unlimited internet plan, then you should ask for a CODA-4582 which is the latest modem deployed by Rogers.  That has the benefit of not having the latency that all of the other Hitron CNG3xxx model modems suffer from.  That latency, within the modem is the result of the processing thru CPU software based routines instead of thru the packet accelerator.  This is an Intel Puma 6 chipset issue that exists for all Puma 6 modems around the world.  Rogers and other ISPs are finally at the point of a near release of a firmware version to resolve that latency, but, I don't believe that the basic CGN3 is on that list just yet.  Reading thru your previous post, it looked like you were pinging one device on your network thru the modem, using another connected device.  Its possible, if you decrease the ping interval down below 1 second to see the high ping times thru the modem.  That is the same situation as running a ping out to the CMTS, which is the next device listed in a trace to anywhere.  So, I wonder if that latency isn't causing some confusion?


In terms of ethernet port dropouts, there seems to be a growing number of instances reported recently.  That's a little strange given that the production firmware versions in the modems has been out for a while now, and thats across most of the modem models.  That makes me wonder if there has been some change to the CMTS configuration recently that is causing these ethernet port disconnects.  There was an issue like this last year, either with the CGN3ASCMR or the CGNM-3552, where the ethernet ports died when the modem lost momentary comms with the CMTS, but a firmware update resolved that.  That same firmware update most likely has not been applied to any other modem model, so, there are some questions that need to be answered regarding the port disconnects.  Fwiw, I run a CODA-4582 in Bridge mode with a Asus RT-AC68U router behind it in full router mode.  That router also has Access Point and Bridge modes available, but neither one of those modes are applicable where the modem is running in Bridge mode.   I've never seen any dropouts with that modem, or with any other Hitron modem that I've run, but, again, the current dropout situation seems to be rather new. 


Can you clarify your network setup so I have a better idea of how its configured?  Maybe its just a matter of terminology, Router mode, Bridge mode, Access Point mode?

Re: CGN3 wired connection dying?

I do not have double NATs. The wifi router is in bridge mode. You could call that access point mode too. Unfortunately, getting it out of that mode isn't easy. I have to wait until everyone is out of town and I get one computer connected via my cell phone before I could attempt any major reconfiguration.


I have to do more research, but there seems to be a different bridge mode on the modem side that shuts down everything, including DHCP. If that is true, then I can de-bridge my wifi router and let it take over DHCP and ethernet. I'm confident that would solve the problem. Unfortunately, the page with the instructions ( doesn't work [Error] Failed to load resource: the server responded with a status of 404 (Not Found) (, line 0). Gotta have those web fonts!


The ping just started as a diagnostic test to see the drop out happen instead of just wondering why the shell isn't responding to keystrokes. It worked fine when I had the machine on wireless. The funny thing is that ping is also a solution. Any outgoing network activity from the Linux machine to the router (or beyond) will re-establish connectivity, even if only for a few seconds. Ping is just local and convenient.


I don't know what CMTS is. I'm just a software developer. I don't like having to do network admin.

Re: CGN3 wired connection dying?

@etresoft the Rogers modems basically have a unified user interface so that the interface is consistent across the various modem models.  The exceptions to the unified interface are new functions which have become possible due to newer technology modems.  All of the Hitron modems have a Gateway mode providing firewall, DHCP, wifi services, etc, etc, and a Bridge mode which turns the modem into just a modem, with no services provided.  In that modem mode, you need a router running in full router mode to provide those services: firewall, DHCP, wifi , etc, etc.


To flip the modem into Bridge mode, you would need to log into the modem, navigate to the BASIC .... GATEWAY FUNCTION tab and disable the Residential Gateway Function.  Save the setting and the modem reboots into Bridge mode.  To access the modem (in Bridge mode) with either a direct ethernet connection or thru the router, you would use as the modems login page address.  That allows you to check the modem's DOCSIS signal levels and DOCSIS Event log, or reenable the Gateway mode if desired.  If you reenable the Residential Gateway Function thru the user interface and save the setting, that will reboot the modem back into Gateway mode with the previous Gateway mode settings intact.  Access to the modem's login page in Gateway mode is either thru, or


You can also run a Factory reset to force the modem from Bridge mode to Gateway mode.  Depressing the recessed reset button at the back of the modem for 30 seconds and releasing it will start a Factory reset and reboot, ending up with the modem in Gateway mode.  However, as a result of running the reset, you will have to reset all of the modem parameters.  


Here is a screen shot of the modem's Gateway Function page.  This is from the CODA-4582.  The CGN3xxx modems will not have the router mode, or SIP ALG enable/disable function.   


Edit:  I've sent a message to one of the mods to have a look at the "Bridge mode setup" web page.  That might take a day or two to sort out. 



3_BASIC - Gateway Function.jpg

Re: CGN3 wired connection dying?

Thanks. I looked at that setting but it sure isn't clear about what it does. I even clicked the help button which then displays "Overflowing text to show how to configure". 


By the way, your screen shot doesn't show up. That's OK. Your description was very good. I can figure out the rest.

Re: CGN3 wired connection dying?

Refresh the page.  The image should show up.  Its available on another browser that I have open, where I'm not logged into the site, so it should be available to everyone. 


One of the moderators has to approve any images that are submitted.  Until then only the image placeholder can be seen.  Looking at the same page with another browser, the image has been approved and can be seen.

Re: CGN3 wired connection dying?

I Plan to Stick Around
I gave up on the CGN3 and moved to the Rocket modem (CGN3ACSMR). Wired ports seem ok now. If you don't hear from me again on this topic, consider it fixed ☺
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