Using OSPF on private ranges to route internet traffic

RouterOS Forwarding Protocols
1

Good evening

We have a lot of public /30s in our network for simple point to point links between base stations and with the shortage of v4 beginning to bite, I wondered is there another way of using internal addressing for these links without OSPF causing issues? In the past, we have tried internal /30s between routers but had customers unable to get internet. Enabling NAT on the core routers solved this but natted everything else despite the customers being given a real IP for their endpoint.

Network segment layout is as follows

Customer router<----PPPoE----->Base station (pppsvr) <-----/30----->Base station <-----/30----->core-router<----internet---->

One idea I had was to change everything to internal addressing and set up MPLS then have a VPLS instance to each base station and run a central PPPoE concentrator in our datacenter. The problems with this setup is loss of the data-center or the concentrator would cause a 100% outage everywhere. It would also require me to take down almost the entire network to implement.

Any ideas would be grateful.

Thanks in advance

Jon

2

I would consider the CGN NAT range for this as it’s not publicly routable

100.64.0.0/10

We use it extensively in our designs for PTP addressing where public addresses would otherwise be used. It works very well.

You can then use a public loopback to NAT the traffic to. Here is an example:

3

You can very easily run multiple PPPoE concentrators to avoid an outage. It also allows you to scale PPPoE connections as needed.

https://stubarea51.net/2018/04/23/pppoe-high-availability-design-incorporating-multiple-access-concentratorsbras/