Wondering if some gurus can help me plan this in my head.

I understand how MPLS and VPLS tunnels work over an OSPF infrastructure and I plan to test and implement this in my OSPF network soon.

I am wanting to move to PPPoE as well and like the idea of having a central PPPoE server connected to the CPE via a VPLS tunnel.

My question is how to make this redundant.
OSPF does an awesome job of making the network redundant but what good is this if the the VPLS tunnel terminates on a single router and a single PPPoE server.

I plan to use Mikrotik as my PPPoE Concentrator and would like to have at least one backup PPPoE Concentrator

Can someone explain how this would be setup? bridging VPLS tunnels? split horizon bridging? these are all things I am not sure if are required to make this work.

I've just built this exact thing using Mikrotik RB2011 and UBNT Toughswitchs. Had an issue with RSTP on a switch but check my other post for that....

In short

On the CPE, have a management VLAN and a Customer VLAN (lets say VLAN 11 & 12). Make sure these packets are tagged back to the Mikrotik.
Create the access ports/trunks as needed on a switch.
Create the VLANs on a port on the Mikrotik.
Create a bridge on the Mikrotik called "Customer" or whatever is good, add the VPLS tunnel and VLAN 12 (customer) to the bridge.
Use split horizon, turn off spanning-tree.
Have a loopback interface for OSPF ID and LDP/Transport on MPLS. Set an admin MAC on the loopback too.
Make sure jumbo frames enabled on switch and check MTU around network supports everything you need.
At the headend/PPPoE end. You will have X amount of terminated VPLS tunnel here. Bridge these together and add the PPPoE server interface to the bridge.

That's a brief of the main things to do.

If it's wireless, use OSPF NBMA.
Use NTP.

I have a figure of 8 looking network with a few spokes running this setup. I had an issue with RSTP but sorted that and it's looking good...

I use PPPoE (Mikrotik) and Mikrotik Userman at the edge. You need scripts for failover/loadbalancing. Juniper etc use PADO delay which Mikrotik need to sort out as it's really useful and simple....

Thanks very much for the reply djmitch

Most of what you did I already understood and had planned to do,
Any reason why you use NBMA OSPF instead of PTP/PTMP? I have found PTP to work great over wireless with mikrotik so far.

For the scripting redundancy, this is really what my question was as I am unsure of what this would look like.

Can you go into more detail on how you might design and script a failover .

from the CPE mikrotik would you have 2 VPLS tunnels going to different routers at your core?
Would that work ? as I understand it PPPoE will automatically choose a PPPoE server to connect to and failover automatically if two are available. With this in mind would you have two tunnels each with a PPPoE server listening on the other end ?

With that configuration you wouldn't even need split horizon bridging right?

I use Ubiquiti for the CPE and 2 tunnels from the hilltop to each PPPoE server (on different routers/sites).

I don't use the script for failover but there are examples out there although PPPoE will connect to whoever responds first if you have more than 1 PPPoE server. For a lot of people, delay PADO would be a lot easier/better than scripts etc.

If your network could loop, you need split horizon but if it's not got a loop, I guess there's no need for split horizon. I use it as I have 2 loops for redundancy.

OSPF PTP is multicast so could still fall foul during peak periods. I've run my network with both PTP,NBMA and default/multicast. All work fine. NBMA seems to be best practice when wireless is involved. Use PTP if it works for you though.

HTH

I just put two PPPOE servers on the same layer 2 segment. Generally the load balancing is really good, at max it hits 60/40 load between the servers.

Is that with a script or just leaving them to get on with it?