Using a VMG8825-T50 with CityFibre

chrisw

I've just had a 100Mbps CityFibre connection installed by Zen Internet. It works fine with the supplied Fritz!Box router with 112M downlink and at least 300M uplink (!) Using the Zyxel, the uplink speed is only 46M. To check if it is an Ethernet problem I've tried a different cable, and connected it through a 1G Ethernet switch. Next, I've connected the Fritz to the ONT then connected the Zyxel to a LAN port on the Fritz, with the Zyxel WAN set to IPoE instead of PPPoE. This setup gives 300+M uplink speed, so the Zylinx is certainly capable of this speed. Any suggestions why the uplink speed is so low?

tonygibbs16

Hi @chrisw

Welcome to the forum.

You seem knowledgeable, so are you able to check what the Connection Status → System Info screen in your Zyxel device is showing for the Ethernet WAN speed and duplex when connected to the Optical Network Terminal (ONT) that Zen installed?

see below extract from the user guide https://download.zyxel.com/VMG8825-T50K/user_guide/VMG8825-T50K_V5.13_5.50.pdf linked from https://www.zyxel.com/uk/en-gb/products/dsl-cpe/dual-band-wireless-ac-n-vdsl2-combo-wan-gigabit-iad-vmg8825-t50k

A hypothesis is that the Ethernet WAN port is not coming up as 1000/Full , i.e. 1Gbps Full Duplex.

Out of interest, what firmware version is your VMG8825-T50 running?

• 5.50(ABOM.8.4)C0 firmware was published in August 2024.

Kind regards,

Tony

chrisw

Hi Tony,

Thank you for your suggestions. I hadn't checked for firmware updates, I had 8.3 installed, so I downloaded the update and installed it. The WAN port is running at 1000M/full duplex. But the firmware update has not solved the problem. I'm still getting the same speeds.

Chris