Sat, Apr 17, 2021 2:22 PM
Looking at my device compatibility with the new 1.2Gb service I have, it claims the cm1200 is incompatible. I know this modem can handle the speeds so what's the story?
1 m ago
Gold Problem Solver
2 m ago
The page at https://www.xfinity.com/support/devices/ lists 5 retail devices approved for 1.2 Gbps. They all appear to have 2.5 Gbps Ethernet ports, the CM1200 does not seem to have one.
It might be possible to get a bit more than 1 Gbps through the modem using a router compatible with its link aggregation, but if Comcast doesn't deliver 1.2 Gbps to the CM1200, I don't think it can provide the full benefit of the 1.0 to 1.2 speed upgrade.
Good morning @Speedi1 and thank you so much for reaching out to our Digital Care Team on our forums page. To ensure your modem is compatible please use the My Device website here https://comca.st/3tx9KV4 to easily check if your device is approved for Xfinity Internet service. My Device shows a database of all approved cable modems. You can also use this site to make sure your modem or router supports your selected Internet speed tier.
What speeds are you currently experiencing? If you are having connection issues, rest assured you've reached the right team to help. What troubleshooting steps have you attempted thus far?
I also own the CM1200 by netgear bought it a few months ago to use with my 1GB Xfinity service. The CM 1200 states it can handle speeds of up to 2GB service. So why is Xfinity not allowing this modem to work with the new 1.2GB service? I already have LAG setup on it.
So I have a asus rt-ax86u router, so if you take 2 of the 1 gig Ethernet ports from that modem, connect to that router using dual wan mode, don’t use lag, I can achieve 1400 Mbps, I don’t have that exact modem, but the dual wan setup is the way to go
so yeah. i also have the rt-ax86u. i connected the 2 cables from the modem to the regular wan port and lan port 4 on the router. make sure you enable wan aggregation in router settings. If your connecting directly to router with a pc use the 2.5g port which is set to lan by default. otherwise if your strictly wireless..any ax capable devices will show higher than 1gig/
Heres the thing. the cm1200 and my modem the motorola mb8600 will provide higher than 1 gig thru wan aggregation. Because its labled as a gigabit router,comcast says its incompatible. This is false. By bonding two ethernet ports on the modem..and connecting the two cables to a compatible router that also supports wan bonding...you will see higher than 1 gig speeds. Just remember that you will need a lan port that is labled for at least 2.5g on the router and your network card in your computer if your hardwired is also rated for at least 2.5g Proof it works just fine.
So even if your modem doesn’t support link aggregation, with a router like the asus rt-ax86u, if you have 2 gigabit Ethernet connections to supply it and use dual wan setup, it will achieve roughly 1400 Mbps, this is just for reference, also the some select asus routers can use the Merlin firmware, which is enhanced asus firmware, the great thing about the Merlin firmware, is you can download the source and compile your own custom firmware