...
Dial-up client uses PPPOE to connect to a L2TP access concentrator (LAC), LAC determines that session should be forwarded through a IP network to the L2TP Network Server (LNS), creates L2TP tunnel and forwards PPP frames to the server where client is authenticated and session established (see diagram below).
At the time of writing this article RouterOS cannot be used in LAC role. For this reason article will demonstrate how to set up very basic network with RouterOS as LNS and Cisco router as LAC.
...