What is "CPE" in this context? It's probably not "Common Platform Enumeration" (my top results for "cpe linux") or "Customer-Premises Equipment." ("cpe networking")
> CPE generally refers to devices such as telephones, routers, network switches, residential gateways (RG), set-top boxes, fixed mobile convergence products, home networking adapters and Internet access gateways that enable consumers to access providers' communication services and distribute them in a residence or enterprise with a local area network (LAN).
I think a CPE could (be/include) a router, but usually it refers to the demarc between the provider's network and the customer's (no matter who owns/manages it).
For a Linux box to be a true CPE you'd likely need somewhat of a specialized card, one that can communicate directly to the next device up the line (e.g, take commercial fiber or cable in, ISDN modem, etc).
If it just shoots out ethernet into some other box next to it, it's likely not a CPE.
Plenty of isps that provide internet over regular ethernet. But it's a ye olde telecom provider term that referred to the phone, that you also didnt own yourself. Doesn't always apply cleanly these days.
Usually it's "something else" that turns into RJ45 (as ethernet has a maximum length) - now if you're in a datacenter you likely can get raw RJ45 Internet).
> CPE generally refers to devices such as telephones, routers, network switches, residential gateways (RG), set-top boxes, fixed mobile convergence products, home networking adapters and Internet access gateways that enable consumers to access providers' communication services
From my understanding any type of device that is used to extend or facilitate provider services is a CPE. So a router just acting as an extender would still be a cpe, as would a modem, as would anything that is on the customer side and facilitates provider services. Only situation a router wouldn't be a cpe is if it was just for a local lan network.