6.2.1 Types of 5G ProSe direct discovery procedures

24.5543GPPProximity-services (ProSe) in 5G System (5GS) protocol aspectsRelease 17Stage 3TS

The following PC3a control protocol procedures are defined:

a) announce request;

b) monitor request;

c) discoveree request;

d) discoverer request;

e) match report;

f) network initiated direct discovery update;

g) announcing alert request; and

h) 5G PKMF address request procedure.

In the following descriptions of PC3a control protocol procedures, the terms "request" and "response" refer to the corresponding PC3a control protocol messages, not to the HTTP request or response. The following procedure descriptions use a single PC3a control protocol message for illustration purposes.

The PC3a control protocol procedures for 5G ProSe direct discovery shall be integrity protected and confidentiality protected using the security procedures defined in clause 5.2.3 in 3GPP TS 33.503 [34].

NOTE 1: A single HTTP request message can contain multiple PC3a control protocol requests and a single HTTP response message can contain multiple PC3a control protocol responses.

When the TLS tunnel between the UE and the 5G DDNMF for transport of PC3a messages is established by the UE according to 3GPP TS 33.503 [34], the 5G DDNMF shall obtain identity of the served UE using the procedures specified in 3GPP TS 33.220 [46] or 3GPP TS 33.535 [47].