Methods, apparatus, systems, architectures and interfaces, performed by a relay wireless transmit/receive unit (R-WTRU) including a transmitter, a receiver, a memory, and a processor, for establishing extended unicast links and management unicast links are provided. The method includes: performing, by the R-WTRU, a link establishment procedure for establishing any number of extended unicast links for relaying traffic between a service-provider WTRU (SP-WTRU) and any number of service-user WTRUs (SU-WTRUs) according to a mapping generated by the R-WTRU, the link establishment procedure including: (1) generating a mapping of any of the extended links and layer 2 (L2) identifiers (IDs) for any of a SP-WTRU, a R-WTRU, and any number of SU-WTRUs, and (2) transmitting a unique relay ID; establishing a management unicast link for the extended unicast links; and applying any number of link management requests received via the management unicast link to associated extended unicast links.