S1 Handover SGW Relocation to cnSGW-C Call Flow
This section describes the S1 handover SGW Relocation to cnSGW-C call flow.

Step |
Description |
---|---|
1 |
MME sends Create Session Request message to GTPC-EP ingress with the following:
Establishes new transaction at GTPC-EP ingress. |
2 |
SGW service POD receives Create Session Request. |
3 |
Create a new transaction S-T1. |
4 |
Validate Create Session Req. |
5 |
NodeMgr allocates TEID. SGW service reads the UPF cache and performs UPF selection. |
6 |
PFCP-EP receives Sx Session Establishment Request from SGW service POD with the following:
|
7 |
PFCP-EP forwards Sx Session Establishment Request to UPF |
8 |
PFCP-EP receives Sx Session Establishment Response from UPF with Created CTEs. |
9 |
SGW service POD receives Sx Session Establishment Response from PFCP-EP. |
10 |
SGW service POD forwards Create Session Response to GTPC-EP ingress. |
11 |
Updated session at CDL. Transaction S-T1 completed. |
12 |
GTPC-EP ingress forwards Create Session Response to MME. |
13 |
GTPC-EP ingress receives Modify Bearer Req with updated eNodB FTEID from MME. |
14 |
GTPC-EP ingress forwards Modify Bearer Req to SGW service POD. Creates new transaction-T2. |
15 |
PFCP-EP receives Sx Mod Req from SGW service POD with the updated downlink FAR and uplink PDR. |
16 |
PFCP-EP forwards Sx Mod Req to UPF. |
17 |
PFCP-EP receives Sx Mod Response from UPF. |
18 |
SGW receives Sx Mod Response from PFCP-EP. |
19 |
SGW service POD sends Modify Bearer Request with updated S5 SGW Control TEID and S5 SGW Data TEID to GTPC-EP. |
20 |
GTPC-EP forwards Modify Bearer Request to PGW. |
21 |
GTPC-EP receives Modify Bearer Response from PGW. |
22 |
SGW service POD receives Modify Bearer Response from GTPC-EP. |
23 |
GTPC-EP ingress receives Modify Bearer Response from SGW service POD. |
24 |
Session updated at CDL. Transaction S-T2 completed. |
25 |
GTPC-EP ingress forwards Modify Bearer Response to MME. |
26 |
MME sends Delete Session Request with SI=1 to old SGW and receives Delete Session Response. Call cleared in old SGW. |