I need to make a transparent L2 tunnel between two locations.
In both locations I have a CCR1072 in which there is only a 10Gb Cogent connection.
I have tried to create a GRE tunnel and a VPLS connection over that tunnel. All this without encryption. But the passthrougt is 600Mb.

I put a small network diagram to try to be more explained: On the contrary I have to comment that it goes over the Cogent network, so the MTU is 1500 and there is no MPLS on his network to try to use.

Of course if instead of using those lines for an L2 I use it for normal connection if 10Gb is available without problems, so that line faults are discarded.

Try to use EoIP tunnels between CCR or run ospf+mpls+vpls. Last will be the best option.

Hello, absolutely the best solution is about using EoIP tunnels, once I configured one of those tunnels between two CCR and the througput was 1Gbps (limited by the gigabit interface that i was using). I've made several test with jperf and bandwithtest and it was 1Gbps of real throughput, that tunnel was used to replicate an entire database of a customer

As you mention MTU=1500: Are customer packets passed being fragmented? The extra processing involved slows things down