If you run the modem in Bridge mode, the modem will apparently provide a second IP address. This has actually come up for discussion in the past, and some have indicated that this is what they do. @RogersMoin has indicated that this can cause some instability in the modem operations, but, no one has ever indicated that they've had any problems doing this.
Can I get the link please ? I can't find it anywhere on rogers.com where I can get a second ip
It's not on Rogers.com.
It's on the Rogers Yahoo control panel... Go to https://na.edit.client.yahoo.com/membercenter , log in with your Rogers Yahoo email address (not your My Rogers/Shomi/etc credentials), go to the "My Account and Billing" tab, then at the right there is a "Add an IP address" link.
I have no idea if it works - this system is at least a decade old and I don't think has been maintained in any way in that time.
Yea found it thank. It's $9.95 for a extra IP address, the thing I'm confused is when the cgn3acsmr is bridged why does the other ports still work for free? I tried it and one thing I noticed I get disconnected from it once in awhile
I think a lot of this has to do with DHCP and how... imprecise... DHCP is.
Back when Rogers started charging for extra IPs, this was in the days of @home, which went bust in late 2001. They ran a very unusual DHCP set up tied to your hostname, so you got a hostname like cr781114-a (yes, that was my @home@ computer name at my parents' 16 years ago) (c means customer, r for Rogers, as opposed to one of the other @home MSOs, 781114 was my customer ID, and -a for the first machine) and you had to set your computer to that hostname so it would send it to the DHCP server. If you paid for another IP, then the machine with hostname cr781114-b would also get an IP from the DHCP. Same thing with cr781114-c, etc. If you changed computers, just give the new computer the right hostname, and it would get the same IP that the old one had been getting. In those days (before dedicated hardware NAT 'routers'), we were plugging hubs (yes, hubs, there weren't cheap residential-grade switches available) straight into cable modems...
Then, as I mentioned, @home went bust, and Rogers moved to a more 'traditional' DHCP setup that didn't do the exotic hostname-based setup. What they can restrict is how many client MAC addresses per cable modem are allowed to get an IP from DHCP... but if you set that number to '1', and a customer (don't forget this was pre-gateway days) changes their computer/router/etc, then oops, the new device wouldn't be able to get an IP without calling tech support or until the previous device's lease expires. Oops. Clearly not ideal... so they had to set the DHCP to allow more than one MAC address per cable modem to allow for device changes.
How, precisely, the DHCP works with these circumstances not known. How this ties into the extra IP offering (which predates this setup) is equally unknown.
If I had to guess, the DHCP gives you 1 IP per modem, plus however many IPs you've purchased, plus some 'wiggle room' for device changes. (Note that Rogers uses 2-day DHCP leases) But that's a complete guess - while my parents did have multiple IPs long ago, the second IP was cancelled around a decade ago when everything was moved behind a single NAT router. And I suspect I am probably the only one here to have had any experience with Rogers' multiple IP offering...
(Don't forget that in bridge mode, the 4 ports at the back of the CGN3 gateways work essentially like that hub plugged into a LanCity/Terayon modem 15 years ago - each device plugged in is talking to the DHCP server and either getting an IP... or not)
I was using two IPs with my CNG2 modem for years without any stability issue. I used my second IP to test connect back into my network and to offer unencrypted guest wifi. IIRC (this is going back a few years when last tested), a max of two IPs are allowed and if a third device is connected the DCHP request will fail. I think DCHP request would fail even if the second device is not connected and the modem had to be rebooted to free the MAC addresses (again, this is from vague memory). I only had use for a second IP so I didn't mess around much with getting more (though, if more were offered I would probably find use for them just because they were free).
I am not sure why your connection would be unstable, but I would start with another modem before trying to purchase another IP. I no longer have this setup because I switch service over the weekend. Once I get the new service setup to my liking, I will be try the second IP, since it also uses the Rogers infrastructure and backend services.
Hope that helps.