Hi folks,

I've just picked up a hAP ax lite LTE6 and am wondering if this type setup would work.

I have a GPON fibre connection, and my ISP provides me with an ONT device in bridged mode with only 1 port enabled.

Due to some crazy power issues here, i'd like to try run an additional, lower powered Mikrotik router as a backup off my ONT's 1 port.

This basically means I will be dialing 2 PPPOE connections (which my ISP allows) off the 1 port from 2 separate devices.

To put it simply, in the below image, I am trying to place 2 routers on a switch, but i'd like to replace the switch with the one mikrotik router.



This would hopefully replace the need for a separate switch by allowing me to connect the one router to a port on the mikrotik, and have that port be bridged straight through to the ONT.



Could anyone please help a total noob on if this is even possible?

Yes it is possible.

Ideally use Winbox, or webfig to configure the router.

Non optimal solution, (but likely near enough)

Summary
Add a new 2 port bridge for Wan connection, create and connect a pppoe client to it.

Roughly what I would do:
Starting from the Mikrotik default configuration with a recent version of RouterOS.

Optional
Quickset: Set up a new LAN IP address and DHCP server configuration (only)
Note
Quickset is often flaky, this function usually works, will need to
disconnect ethernet cable from laptop briefly after applying change to
acquire new IP Address.

Setup

• Wifi: Disable Wifi interfaces. (Or configure as required)
• Bridge: Make a second bridge named bridgewan, turn off RSTP on the new bridge.
• Bridge/ Ports: Add ether1 and move ether2 to the bridgewan
• Interfaces: Possibly Add a vlan interface, and attach it to bridgewan (if pppoe needs to be on a VLAN)
• PPPoE: Attach a new pppoe client to either bridgewan, or the vlan interface.
• IP/ DHCP Client: Disable the default IP DHCP Client.
• Interfaces/ Interface List: Add the bridge and pppoe interface and vlan interface (if used) as members of the WAN interface list.
• Ensure the new bridge has hardware offload enabled and running on it.
  (Likely by turning off HW offload on each bridge port on original bridge)

Connect ether1 to the ONT
Connect ether2 to the Unifi
ether3 and ether4 are the Hap's Lan interfaces.

Optimisations
Turn off unused services. IP Services:
Maybe turn off sip nat helper. IP/ Firewall/ Service Ports:

If you remove one of the other ports (ether3, ether4) from the original bridge and use it
as a management interface or if little traffic will flow between Lan ports ether3 and ether4
no further optimisation is required.

Otherwise, at a later time you can study the bridge vlan filtering
documentation and create a single vlan filtering bridge with all ports
hardware offloaded.

Edit: Updated Interfaces/ Interface List: Add the bridge, and pppoe interface and vlan interface (if used) as members of the WAN interface list.