Section: 6.1.2 Types of ESM procedures
Content: Two types of ESM procedures can be distinguished: 1) Procedures related to EPS bearer contexts: These procedures are initiated by the network and are used for the manipulation of EPS bearer contexts: - default EPS bearer context activation; - dedicated EPS bearer context activation; - EPS bearer context modification; - EPS bearer context deactivation. This procedure is initiated by the network or by the UE and is used for the transport of user data via the control plane: - transport of user data via the control plane procedure. 2) Transaction related procedures: These procedures are initiated by the UE to request for resources, i.e. a new PDN connection or dedicated bearer resources, or to release these resources: - PDN connectivity procedure; - PDN disconnect procedure; - bearer resource allocation procedure; - bearer resource modification procedure. This procedure is initiated by the ProSe UE-to-network relay and is used for the manipulation of EPS bearer contexts: - remote UE report. When combined with the attach procedure, the PDN connectivity procedure can trigger the network to execute the following transaction related procedure: - ESM information request procedure. When combined with the attach procedure, if EMM-REGISTERED without PDN connection is supported by the UE and the network and no PDN connectivity procedure is initiated during the attach procedure, the UE or the network executes the following transaction related procedure: - ESM dummy message procedure. A successful transaction related procedure initiated by the UE triggers the network to execute one of the procedures related to EPS bearer contexts. The UE treats the start of the procedure related to the EPS bearer context as completion of the transaction related procedure. During procedures related to EPS bearer contexts, the MME and the UE shall not initiate the transport of user data via the control plane procedure until the ongoing procedure is completed. NOTE 1: The UE determination of the completion of the transport of user data via the control plane procedure is left to the implementation. NOTE 2: NAS signalling prioritization with respect to the transport of user data via the control plane cannot be guaranteed in the downlink direction in this version of the specification. Except for the remote UE report procedure and ESM information request procedure, during transaction related procedures, the MME and the UE shall not initiate the transport of user data via the control plane procedure until the ongoing procedure is completed. The following ESM procedures can be related to an EPS bearer context or to a procedure transaction: - ESM status procedure; - notification procedure.