A device for service layer registration, the device forming a node and comprising: a processor; and a memory (44, 46) coupled with the processor, the memory comprising executable instructions that when executed by the processor cause the processor to effectuate operations comprising: sending, by a first application of the device, a first message comprising a registration request for a first service of a service layer to a first registrar entity; receiving a second message that is responsive to the first message, the second message comprising a first list of one or more identifiers of one or more services granted by the first registrar entity for the first application, and a mutuality, wherein the mutuality indicates whether the first service is bi-directional in that the first service is provided by the first application to the first registrar entity and the first service is provided from the first registrar entity to the first application or unidirectional in that the first service is only provided from the first registrar entity to the first application; responsive to the second message, sending, by the first application, a third message comprising a registration request for a second service of the service layer to a second registrar entity; and receiving a fourth message that is responsive to the third message, the fourth message comprising a second list of one or more identifiers of one or more services granted by the second registrar entity for the first application, wherein the first application is simultaneously registered with the first registrar entity and the second registrar entity, wherein the service layer is a software middlelayer layer supporting value-added service capabilities through a set of application programming interfaces, APIs and underlying network interfaces. a processor; and a memory (44, 46) coupled with the processor, the memory comprising executable instructions that when executed by the processor cause the processor to effectuate operations comprising: sending, by a first application of the device, a first message comprising a registration request for a first service of a service layer to a first registrar entity; receiving a second message that is responsive to the first message, the second message comprising a first list of one or more identifiers of one or more services granted by the first registrar entity for the first application, and a mutuality, wherein the mutuality indicates whether the first service is bi-directional in that the first service is provided by the first application to the first registrar entity and the first service is provided from the first registrar entity to the first application or unidirectional in that the first service is only provided from the first registrar entity to the first application; responsive to the second message, sending, by the first application, a third message comprising a registration request for a second service of the service layer to a second registrar entity; and receiving a fourth message that is responsive to the third message, the fourth message comprising a second list of one or more identifiers of one or more services granted by the second registrar entity for the first application, wherein the first application is simultaneously registered with the first registrar entity and the second registrar entity, wherein the service layer is a software middlelayer layer supporting value-added service capabilities through a set of application programming interfaces, APIs and underlying network interfaces. sending, by a first application of the device, a first message comprising a registration request for a first service of a service layer to a first registrar entity; receiving a second message that is responsive to the first message, the second message comprising a first list of one or more identifiers of one or more services granted by the first registrar entity for the first application, and a mutuality, wherein the mutuality indicates whether the first service is bi-directional in that the first service is provided by the first application to the first registrar entity and the first service is provided from the first registrar entity to the first application or unidirectional in that the first service is only provided from the first registrar entity to the first application; responsive to the second message, sending, by the first application, a third message comprising a registration request for a second service of the service layer to a second registrar entity; and receiving a fourth message that is responsive to the third message, the fourth message comprising a second list of one or more identifiers of one or more services granted by the second registrar entity for the first application, wherein the first application is simultaneously registered with the first registrar entity and the second registrar entity, wherein the service layer is a software middlelayer layer supporting value-added service capabilities through a set of application programming interfaces, APIs and underlying network interfaces.