A user equipment (UE) is configured to communicate with a further UE via a sidelink (SL). The UE encodes traffic for transmission to the further UE, wherein the traffic comprises a payload and a medium access control (MAC) subheader, wherein the MAC subheader indicates whether the payload corresponds to non-routed traffic between the UE and the further UE or routed traffic between either one of the UE or the further UE and a base station, wherein an other one of the UE or the further UE functions as a relay for the routed traffic and transmits the traffic.