FTTH Question - UK Modem question


I am lucky enough to have fibre to the home, in my new property in the UK. Am I right in saying that for when you have FTTH the modem is installed permanently at the property and therefore all you need is a router and not just a modem-router. This is useful because I have Alien routers and can therefore sell the modem-router supplied by the ISP.

Thanks for any wisdom!

Be very careful selling your ISP provided router.
Read the small print because things have changed from a few years ago. With many UK ISP’s the router remains their property.
If you ever cancel your services they will charge you if you do not return it.

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Not the wisdom I wanted but gratefully recieved, thanks for the tip!

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Is your FTTH with BT, Sky, Talk Talk or other.

You should always keep hold of the ISP provided Router, if you ever need to troubleshoot an issue they wont help you unless you are using their gear.

So with FTTP/FTTH you are having usually an ONT Modem in the property which converts the Fibre to Ethernet, this bit is usually owned by the infrastructure (not always the ISP), Openreach, City Fibre etc but in many cases these days their are other smaller providers like Gigaclear, Truespeed which are local to the area and install their own ONT. This bit is usually bolted to the wall in either case.

Yes inded you can usually use your own router, you need to hook up the WAN interface of your own Router to the Ethernet port of the ONT Modem but its not as simple as that usually. Your router will need to authenticate and grab an IP for its WAN port.

In alot of cases this is pretty simple, grab your username and password from the ISP and configure the WAN port as PPPOE with credentials. Problem is there are quirks, once I can think of is Sky, they use DHCPv6 PD to authenticate in some areas and something called Option 61 in others. BT apparently just need a dummy username and password and PPPOE, TalkTalk looks like they automatically authenticate but you need a VLAN ID and DHCP…Vodafone use PPPOE…

So depending on your provider do the research before you start screwing around with it as there is quite a few different scenarios to consider.

But keep the ISP provided gear.

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Thanks so much for such an incredibly informative post! I will keep the router!

In the days that have passed I worked out how to connect my Amplifi alien direct to the ONT and it worked straight away using PPPOE and the standard user name - no other work necessary! As a test I also connected my mac directly! I had no idea you could ever attach directly in this way!

But overall very pleased I only have to use my router now, which is small and elegant, and also only have one device down there which is great

No problem, I am moving to FTTP myself soon so ive done alot of research on how to get my ER-X to work just the same as it does now for my Cable Broadband, currently it just uses DHCP to grab an IP and authenticate, if authentication is even happening there, I think its taken care of by the modem tbh in that scenario.

Anyway, so I a moving away from the simple DHCP config and will need to configure PPPOE, how have you currently got yours configured?

What exactly do you mean by configured? Besides selecting PPOE and logging in with the standard passwords, I left the rest of the settings the same, both for the Mac connection and the Router.

Okay cool, just all the default stuff, theres alot of chat about MTU settings and MSS Clamp for PPPOE which can help. Was just checking how much you have messed around with.

Who are you with?

No it seemed really easy to be honest.

I have the open reach ONT in the cupboard - and my provider is Seethelight which is one of those from the closed network of providers, the name of which I cannot remember

Hey when I was in Exeter I had seethelight, I’m sure of it. That was yonks ago and the modem then was not the small type you get nowadays, it was the same size as the router more or less!

I think for fibre there is no difference between the providers except for stuff like customer service - but the underlying network quality and reliability should be the same

Yeah that’s true if you are with an Openreach or similar based service.

If you are lucky enough to have one of the 3rd parties they will offer much better upload speed, usually the same as download. Truespeed for example I could get 600/600 if I lived a couple houses further down the road.

Still Full Fibre will be a good upgrade over Cable which is a very noisy provision in alot of places, Openreach is all I can get however so that’s Sky, TalkTalk, Vodafone, BT etc