Inter-MME Handover and Multi-PDN Handling Active-Idle Transition with ULI Change Call Flow
This section describes the Inter-MME Handover and Multi-PDN Handling Active-Idle transition with ULI change call flow.

Repeat the steps provided in the Table 1 for PDN1 and PDN2 with respective transaction S-T1 and S-T2.
Step |
Description |
---|---|
1, 2, 3, 4 |
Received Modify Bearer request for both the PDNs (PDN1 and PDN2) at SGW-Service POD with new MME control F-TEID and new ULI. There is no eNodeB F-TEID present in Modify Bearer request.
|
5, 6 |
Received Sx Modification request from SGW-Service POD > PFCP-EP POD with APPLY ACTION as BUFFER. Sx Modification request is forwarded to UP. |
7, 8 |
Received Sx Modification response from UP > PFCP-EP POD. Sx Modification response received at SGW-Service POD. |
9, 10 |
Received Modify Bearer request from SGW-Service POD > S5 GTPC-EP POD with updated ULI. Modify Bearer request is received at PGW. |
11, 12 |
Received Modify Bearer response from PGW > S5 GTPC-EP POD. Modify Bearer response received from S5 GTPC-EP POD > SGW-Service POD. |
13 |
SGW-Service POD forwards Modify Bearer response to GTPC-EP POD ingress. |
14, 15 |
Session updated at CDL. Transaction S-T1 is complete. GTPC-EP POD forwards Modify Bearer response to MME. |