WDS Bridge, PPPoE, PTMP Wireless, and VLANs oh my!

RouterOS General
1

Problem:

Multiple WDS interfaces on PTMP access points are causing packet duplication to the point where performance and latency is suffering. Routing would be ideal, however it would require changing settings on 500+ client routers already setup for PPPoE.

Objective:

eliminate the packet duplication, but maintain Layer2 connectivity to authenticate PPPoE clients.


Network Topology:

Brief Outline

Crude outline, but basically at the main location we have our upstream bandwidth going to the R1 router, the it goes through the switch to various Mikrotik PPPoE Access Concentrators (AC2). Each AP comes into it’s own port on the Access Concentrator. We have some PTP links for our high traffic sites, other sites are fed through a PTMP setup with WDS bridging. This has become a problem because of the increasing number of interfaces on the bridge is causing packet duplication, resulting in loss of throughput and increased latency.

Is there any way I can accomplish my objective through VLANs, or using a less attractive protocol like EoIP to tunnel the traffic back to the AC?

I was thinking of creating (on AP2) a unique vlan on ether1 and bridging it with a single wds interface. Then creating the other end of that VLAN on the Access Concentrator and create a PPPoE server on the VLAN interface. The question I guess is, can a VLAN interface be unnumbered, and does this sound feasible?

Routing would definitely be my preference, but this company has committed to PPPoE for authentication and accounting and there’s no segmentation between network distribution and access layers. In many cases there are clients and other Access Points connecting through the same wireless interface.

2

Do you use wds between CPE’s and AP2?

And by packet duplication, do you mean packets are duplicated in error or in the nature of bridges?

3

In some cases yes, most of our CPE’s are Tranzeo’s (they use MAC-NAT im assuming) some of the longer range links are MT in Station-WDS, which I’m now starting to rethink due to the amount of packet duplication due to the bridge configuration…

Yes, I mean packet duplication based on the nature of a bridge.

4

Do you have that much broadcast traffic on your network? After all, non-broadcast traffic should not be ‘duplicated’ but just send out on the (bridge member) interface on which the destination MAC can be reached…

–Tom

5

That is assuming the bridge knows which port to forward the unicast packet. If the bridge does not know (destination address is not in “host table”) then it will be treated like broadcast (flooded on all ports except incoming port).

Those are some solid objectives! :stuck_out_tongue:

Bridge filters can be applied to help reduce bandwidth waste…
You could avoid wds and use routeros cpe’s to do the client connections.
Divide the lans.
Terminate PPPoE on AP.

The network administrators most important objective is damage control.