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.

Idle-Active Transition with Intra MME HO Call Flow
Idle-Active Transition with Intra MME HO Call Flow Description

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.