I recently upgraded to gigabit internet from Xfinity - 1000Mbps down, 300Mbps up - and they sent me an XB7 or XB8 modem.
Unfortunately, the Wi-Fi transmitter on the device cannot be turned off. The home, guest, and xfinitywifi networks can be disabled, but the "Hidden" network used for Xfinity Home Security cannot be. Enabling bridge mode on the modem's router (so it's "just a modem" without the possibility of routing over Wi-Fi), did not turn off the transmitter.
Here is what I found out about purchasing my own modem.
In order to replace the XB7 modem, you need four devices:
1. A modem - to convert the coaxial signal to ethernet
2. A router - to assign IP addresses and route traffic from the modem (WAN) to the LAN
3. A switch - connect multiple ethernet ports to support multiple devices (most routers include this)
4. Wireless access points - Wi-Fi receivers/transmitters (many routers include this)
Amazon has 3 Xfinity voice modems:
1. Netgear CM2050V: $300 - up to 2.3Gbe
2. Arris Surfboard T25: $104 refurbished - either 950Mbe or 800Mbe download, depending on source.
3. Netgear Nighthawk 1150v: $140 refurbished - Up to 960Mbe
There are a number of good gigabit routers:
1. TP-Link ER605 - gigabit router, cheap, easy. No link aggregation (because CPI can't handle it)
2. MicroTik hEX S - amazing feature set, non-user-friendly. Might support link aggregation
3. Google WiFi - supports mesh Wi-Fi and probably has great software, requires switch
4. ASUS EBG15 - might support WAN link aggregation (according to AI)
For a single gigabit modem, link aggregation is not needed. However, the modems listed above claim to be suited for Xfinity plans "up to 2Gbe", but those are lies. If the modems did support 2Gbe speeds, link aggregation would enable connecting the modem to the router with 2x 1Gbe connections.
Unfortunately, the kicker to that there are no voice modems in the Next Gen Speed Tier in Xfinity's list of supported modems. According to Reddit, modems outside this tier have upload speeds limited to 24Mbps.
If this had of worked out, I would have tried the Arris Surfboard T25 and TP-Link ER605, but it's not worth $200 to test if it would indeed have limited upload speeds. I'll have to try something else...
