FTTP with Zen and Cityfibre - Asus AX88u and AX86u

Hello, I hope someone out there with the necessary technical knowledge can help. I recently upgraded to Zen's FTTP network which is installed and run by Cityfibre. It's an asynchronous 900Mb connection and I am using the supplied 7530 Fritz!box. Prior to that I was also with Zen on ADSL using my own equipment - An Asus RT-AX88U and a DrayTek Vigor130 modem. Theoretically I can just connect my ASUS to the Callix ONT and everything should work. That is not the case. No matter what settings I use - PPPoE, static IP, automatic ip etc, setting the VLAN to the figure in my Zen portal, cloning the 7530 MAC, using the built in wizards - the connection either fails to sync, syncs with some errors or syncs and then won't route. Zen are no help at all as they don't support 3rd party equipment but they have assured me they are not stopping anyone from using their own equipment. I have tried with both the routers mentioned in the subject. The 88u is running the latest merlin firmware and the 86u is running stock. I can post logs from the 88u if needed - The 86u was borrowed to see if it would work. The Wifi signal from the 7530 just isn't up to the job in my house and I'm not prepared to pay Zen extra just to get a better router when I've already got one that's more than up to the task. Also it is not possible to configure the 7530 as a modem only and to then use the 88u as a router.

Hope someone can help. Thanks in advance for reading.

How are you setting the VLAN on the Asus?

Reading instructions for another CityGibre ISP you need to go to: LAN > IPTV tab select the "manual" profile and set the VLAN ID to 911

Looks like this on my ax86u running Merlin.

Edited by j0hn83 (Sun 19-Sep-21 01:10:27)

Thanks, that's exactly how it looks on mine. Zen said the VLAN is 70 and that doesn't work either. I've also tried 101.

Try 911 , or you've tried that already? No idea then sorry.

Edited by j0hn83 (Sun 19-Sep-21 02:39:36)

What do the logs on the router say?

As a stop-gap while you try and get the Asus working is it possible to leave the network/DHCP stuff to the Fritzbox but turn the WiFi off on that and use the Asus as a WAP?

In reply to a post by Ax88u_Ax86u:

It's an asynchronous 900Mb connection

You mean symmetric?

You could capture the packets between the Zen Fritz!box router's WAN port and the ONT by putting a switch in between with a mirror port, and using wireshark/tcpdump to capture packets. Then you'd be able to see the PPPoE packets and their VLAN tags, then configure the Asus to match. Assuming you had access to such a switch.

You could also rule out problems with Asus firmware by plugging a PC/laptop directly into the ONT, configuring PPPoE with a VLAN tag, and see if you can bring the link up that way.

However, a much simpler solution would be to keep the FB router for routing, and use your Asus just as a wireless access point. You'd need to disable the DHCP server on the Asus, then connect its LAN side to a LAN port on the FB. If you wish, you could then disable wireless on the FB entirely.

In reply to a post by Ax88u_Ax86u:

Also it is not possible to configure the 7530 as a modem only and to then use the 88u as a router

This wouldn't apply to FTTP anyway. The ONT is the "modem", performing essentially the same job as your Draytek Vigor130 did for your ADSL setup. Both of them present Ethernet to the router.

Thanks for the reply. If that's the correct term then yes (same speed up and down). I do have a switch so I'll try that suggestion sometime this week when I've got spare time and if that doesn't help I'll try the other options.

Thanks for the reply and yes I'm going to try that in the meantime.

Thanks but yes I've tried that already.