I am thinking to use this swithch as a simple gateway MPLS + OVPN and simple L3 routing. Did anyone tried it for such purpose. How does it performs? . Indeed there is a very small amount of RAM on this switch compared to what has the CRS317 or what others do on the market. So it's surprising for this price.

CCR2216 is what you want for MPLS PE or P roles which has to be processed in CPU. The CRS518 is better suited for L2 switching or more basic L3 configurations without MPLS.

ok I see. that's too bad we don't have a switch like the CRS317 in the middle I will try for now to play with the CCR2004 and use the 100G switch only for the transport then.