5G/NR - NAS Home : www.sharetechnote.com
5GSM(5G Session Management)
5GSM is very complicated process described in about 100 pages for overall functionaligy in 24.501-6 and around 40 pages for NAS signaling message handled by 5GSM in 24.501-8.3. You would easily get lost if you directly jumping into reading the details. My recommendation is to try to get familiar with the following statemachine to the point where you can draw the statemachine by hands and then read the specification as-you-need basis.
< 24.501-Figure 220.127.116.11.1.1: The 5GSM sublayer states for PDU session handling in the UE (overview) >
< 24.501-Figure 18.104.22.168.1.1: The 5GSM sublayer states for PDU session handling in the network (overview) >
NAS Signaling Procedures Handled by 5GSM
Followings are the list of NAS signaling (OTA procedure) handled by 5GSM. I think these message (process) list would give more concrete idea to most of the readers since analyzing OTA message would be pretty common practice. I will create separate notes for each of these process and put the link as I complete the note... but not sure how long it will take to complete all of them, but I will try to complete at least 5G specific process as early as possible. For most of other procedures, I think you can apply your LTE knowledge. Each of NAS messages involved in each of these procedures are described in 24.501-8.3. As you see, 5GSM is just all about PDU session.