A method to establish an optimized frame format used by a first compute node (21) acting as ingress PE and a second compute node (22) acting as egress PE in the transport of
overlay ethernet traffic containing an IP
payload from the source
overlay endpoint attached to or hosted in the first compute node (21) to the destination
overlay endpoint attached to or hosted in the second compute node (22) through a
Multi Protocol Label Switching, MPLS,
underlay network (2), where the frame format is a conventional MPLS tagged
ethernet frame format, wherein an MPLS
label stack is inserted between the
ethernet header and the IP header of the overlay
ethernet frame, where the single ethernet header carries the destination and source overlay
Media Access Control, MAC, addresses when the frame was originated from the source overlay endpoint, where the MPLS header of the frame comprises a top
label with the
Label Switch Path, LSP,
label towards the destination
Provider Edge, PE,
router, ie. egress PE, and a bottom label, e.g. an optimization MPLS label, holding information enabling the forwarding mechanism in the egress PE
router to restore the original destination and source overlay MAC addresses.