Can I run a layer 2 Ethernet test to a loopback or does it require another testset at the far end?

Can I run a layer 2 ethernet test to a loopback or does it require another testset at the far end?

If the circuit under test is layer 2 aware (switches or routers that are processing mac information) then another testset is required at the far end or some layer 2 device that can be forced into a logical (mac swapping) loopback. In a logical loopback the device will swap the source and destination mac addresses before re-transmitting the frames. If the circuit under test is pure transport equipment that is not layer 2 aware, then any form of loopback (hard or soft) can be used as mac swapping is not required.