I don't know if it's the case in Germany, but here in France consumer FTTH networks are of the GPON persuasion. These need to handle encryption and be able to properly register on the tree, so I'm not completely shocked they require some form of ISP-provided device to terminate the fiber connection.

There's also a EU law which says that users should be able to bring their own modems / routers, so AFAIK providers say that this particular terminal device is still "on their side of the network".

I've seen such devices come in two varieties.

One is a separate device which plugs on the optical network, does the encryption and stuff, and then exposes an ethernet port which is connected to the actual router which does wifi, etc. With SFR and Bouygues, it was trivial [0] to replace the ISP-provided router with one of your choosing. You get the normal external IPs and you do your thing. The ISP router sleeps in its box in storage. This was my setup up until a few years ago, with both these providers. Now SFR has moved to CGNAT, but the setup is the same, so I expect users to still be able to switch routers (but I haven't tested, since I'm not a client anymore).

Then there's Free, who provides a single device that connects to the fiber, does routing, wifi, etc. In this case, it's possible to flip a switch in its settings for it to act as a bridge (don't know how wifi behaves in this case, if it stays on). It then only accepts a single downstream client, which gets the external IP. SFR had a similar setup for DOCSIS.

I'm not familiar with how Orange, the biggest operator, functions. But I understand they have a general tendency to be a PITA so YMMV with them.

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[0] For Bouygues, this device only talked on a tagged VLAN100 for some reason. On the SFR, the network expected you to send a client id in the DHCP request.

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B1FIDO 4 hours ago | parent | next [-]

The term you're looking for is "demarc" or: https://en.wikipedia.org/wiki/Demarcation_point

This is the physical boundary of a network, in telecommunications. This is the junction where the service provider can point and say "that's our equipment on this side". So it helps to narrow down the troubleshooting.

Often, if you have a telephone landline, you will see your demarc take the form of a gray RJ11 box with a small self-plug in it. It would be common practice to plug a phone into that box directly, then you've eliminated the "inside wiring" in the house.

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DannyBee an hour ago | parent | prev [-]

The 8311 discord is a great source of technical info and help on using your own PON equipment of various sorts with providers

	▲	vladvasiliu an hour ago \| parent [-]
		I've seen things about this, but I'm not convinced there's enough value in going to great lengths to replace that particular piece of equipment. In the case where the terminating equipment is a small box that exposes ethernet, with no routing or otherwise interfering the function of my own router, I think it's good enough. An argument could be made for the all-in-one devices, like saving some power. I get the geek factor, and it's one of the reasons why I run my own router, but for this specific bit, which needs to be fairly well integrated with the ISP's network, combined with their usual abysmal support, I think it's a better bet to just leave it alone.