4 General description
24.5383GPPEnabling MSGin5G ServiceProtocol specificationRelease 17TS
The MSGin5G Service (message service for MIoT over 5G System) is basically designed and optimized for massive IoT device communication including thing-to-thing communication and person-to-thing communication. The MSGin5G Service provides messaging communication capability in 5GS including the following message communication models:
a) Point-to-Point message;
b) Application-to-Point message/ Point-to-Application message;
c) Group message;
d) Broadcast message.
The MSGin5G Service support the message exchanging between the following UE types:
a) MSGin5G UE:
1) light weight Constrained UEs (e.g. sensors, actuators) and
2) Unconstrained UEs with advanced capabilities (e.g. washing machine, micro-ovens).
b) Legacy 3GPP UE.
c) Non-3GPP UE.
The MSGin5G Client contained in the MSGin5G UE communicates with the MSGin5G Server over the MSGin5G-1 interface (see 3GPP TS 23.554 [2]). CoAP specified in IETF RFC 7252 [5] is used as the basic transport protocol of MSGin5G service in this reference point and shall be supported by the MSGin5G Client and MSGin5G Server. For supporting sending/receiving MSGin5G message for the MSGin5G Client contained in Constrained UE, the transport protocols of MSGin5G-6 interface is also CoAP specified in IETF RFC 7252 [5].
An MSGin5G UE-1 may be a Constrained UEs which does not have enough capability to communicate with MSGin5G Server. If allowed by configuration, an Unconstrained UE MSGin5G UE-2 may act as an MSGin5G Gateway UE or an MSGin5G Relay UE to MSGin5G UE-1. In this scenario, the MSGin5G UE-1 communicates with the MSGin5G UE-2 over the MSGin5G-5 and/or MSGin5G-6 interfaces (see 3GPP TS 23.554 [2]).
Additionally, the MSGin5G Client(s) may interact with SEAL Clients over the SEAL-C reference point specified for each SEAL service as specified in 3GPP TS 23.434 [3]. The MSGin5G Server(s) may interact with SEAL Servers over the SEAL-S reference point specified for each SEAL service as specified in 3GPP TS 23.434 [3]. The interaction between a SEAL Client and the corresponding SEAL Server is supported by SEAL-UU reference point specified for each SEAL service as specified in 3GPP TS 23.434 [3].
By means of using the MSGin5G-1 interface, the following aspects can be provided:
a) MSGin5G UE registration and de-registration towards the MSGin5G Server;
b) MSGin5G message delivery and MSGin5G message delivery status report; and
c) Messaging Topic Subscription.
By means of using the MSGin5G-5 interfaces, the following aspects can be provided:
a) Constrained UE registration and de-registration towards the MSGin5G Gateway UE; and
b) The exchanging of message and message delivery status report between Constrained UE and MSGin5G Server by using MSGin5G Gateway UE.
By means of using MSGin5G-6 interfaces, the following aspects can be provided:
a) Constrained UE registration and de-registration towards the MSGin5G Server by using MSGin5G Relay UE; and
b) The exchanging of MSGin5G message and MSGin5G message delivery status report between Constrained UE and MSGin5G Server by using MSGin5G Relay UE.
The necessary 5GC Network Capabilities, e.g. device triggering, may be used in MSGin5G Service as specified in 3GPP TS 23.554 [2]. The device trigger is delivered to the MSGin5G Client via SCEF/NEF and the Core Network as specified in 3GPP TS 23.502 [17] and is out of scope of this document.