Idle-Active Transition with Intra MME HO Call Flow
This section describes the current call flow with intra MME handover (NSA MBR) for moving from eNodeB to gNodeB.

Step |
Description |
---|---|
1 |
MME sends Release Access Bearer (RAB) request to SGW-service. |
2 |
SGW-service sends Sx Modify Request for IMS PDN to UPF. |
3 |
UPF sends Sx Modify Response for IMS PDN to SGW-service. |
4 |
SGW-service sends Sx Modify Request for Data PDN to UPF. |
5 |
UPF sends Sx Modify Response for Data PDN to SGW-service. |
6 |
SGW-service sends the Release Access Bearer Response message to MME. |
7 |
MME sends Service Request MBRequest for IMS PDN to SGW-service. |
8 |
SGW-service sends Sx Modify Request for IMS PDN to UPF. |
9 |
UPF sends Sx Modify Response for IMS PDN to SGW-service. |
10 |
SGW-service sends ULI Update MBRequest for IMS PDN (Service Request MBR) to PGW. |
11 |
PGW sends ULI Update MBResponse for IMS PDN (Service Request MBR) to SGW-service. |
12 |
SGW-service sends MBResponse for IMS PDN to MME. |
13 |
MME sends Service Request MBRequest for Data PDN to SGW-service. |
14 |
SGW-service sends Sx Modify Request for Data PDN to UPF. |
15 |
UPF sends Sx Modify Response for Data PDN to SGW-service. |
16 |
SGW-service sends ULI Update MBRequest for Data PDN (Service Request MBR) to PGW. |
17 |
PGW sends ULI Update MBResponse for Data PDN (Service Request MBR) to SGW-service. |
18 |
SGW-service sends MBResponse for Data PDN to MME. |
19 |
MME sends intra MME HO (NSA) MBRequest for Data PDN to SGW-service. |
20 |
SGW-service sends Sx Modify Request for Data PDN (NSA MBR) to UPF. |
21 |
UPF sends Sx Modify Response for Data PDN (NSA MBR) to SGW-service. |
22 |
SGW-service sends ULI Update MBRequest for Data PDN (NSA MBR) to UPF. |
23 |
UPF sends ULI Update MBResponse for Data PDN to SGW-service. |
24 |
SGW-service sends MBResponse for Data PDN (NSA MBR) to MME. |