This amendment contains extensions to the first version (2004) of ITU-T Rec. G.8012/Y.1308, related to the addition of:Ethernet over MPLS;Ethernet over RPR.This amendment incorporates the frame format of provider bridges and deletes specifications of length encapsulation of client data since that encapsulation is not used for Ethernet over Transport. The two Ethernet over Transport NNIs and the provider bridge frame were already considered for the first version of this Recommendation, but the standards defining these frames(ITU-T Rec. Y.1415, IEEE 802.1ad and IEEE 802.17) were not approved at that moment.