OSPF redundancy via Wireless ring plus PPPoE and External Radius support

[me_sanay]

Dear all,

I am planning a routed wireless ring consisting of 6 towers as per the network diagram attached.
I plan to install 1-4 Access points under one tower. I intend to use the SG-2440 firewall under each tower.

Considering this firewall has only 4 Gigabit ports, I intend to use a switch in between to connect the access points via a single port in the firewall.

However to maintain redundancy, I plan to run OSPF by connecting the wireless ring to 2 ports of the firewall.
The other purposes of this firewall will be to function as a PPPoE server to restrict bandwidth policies and act as a proxy to forward Radius requests to an external billing server.

I had planned to install a Mikrotik router but considering the more powerful firewall functions of PFSense, I think it will be a better choice.

In summary, I want to use this firewall for the following specific services.

(1.) OSPF for redundancy
(2.) PPPoE Server for rate limiting
(3.) Forward radius requests to external Radius server
(4.) Firewall and Graphing.

I would be grateful to hear from anybody if they have done this before or can provide further information if the above can be accomplished with the SG-2440 firewall.

Thanks,

Sanay