S1 Handover SGW Relocation with Bearer Context Marked for Removal Call Flow
This section describes the S1 handover SGW relocation with bearer context marked for removal call flow.

Step |
Description |
---|---|
1 |
GTPC-EP ingress receives Create Session Request from MME with the following:
Establishes new transaction at GTPC-EP ingress. |
2 |
GTPC-EP ingress forwards Create Session req to SGW service POD. |
3 |
SGW service POD receives Create Session Req. Create a new transaction S-T1. |
4 |
Validate CSReq. NodeMgr allocates TEID. |
5 |
SGW service reads UPF cache and performs UPF selection. |
6 |
PFCP-EP receives Sx Session Establishment Req from SGW service with the following:
|
7 |
PFCP-EP forwards Sx Session Establishment Req to UPF. |
8 |
PFCP-EP receives Sx Session Establishment Response from UPF with Created CTEs. |
9 |
SGW service receives Sx Session Establishment Response from PFCP-EP. |
10 |
SGW forwards Sx Session Establishment Response to GTPC-EP ingress. |
11 |
Session updated at CDL. Transaction S-T1 completed. |
12 |
GTPC-EP ingress sends Create Session Response to MME. |
13 |
GTPC-EP ingress receives Modify Bearer Req with the following:
|
14 |
GTPC-EP forwards Modify Bearer Req to SGW. |
15 |
Create a new transaction S-T2. PFCP-EP receives Sx Session Modification Req from SGW service POD with the following:
|
16 |
PFCP-EP forwards Sx Session Modification Req forwarded to UPF. |
17 |
UPF sends Sx Modification Response to PFCP-EP |
18 |
PFCP-EP forwards Sx Modification Response to SGW service POD. |
19 |
SGW service POD sends Modify Bearer Req 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 |
GTPC-EP forwards Modify Bearer Response to SGW service POD. |
23 |
SGW service POD forwards Create Session Response to GTPC-EP ingress with cause Accepted for both Bearer Contexts. |
24 |
Session updated at CDL. Transaction S-T2 completed. |
25 |
GTPC-EP ingress sends Modify Bearer Response to MME. |
26 |
MME sends Delete Session Request with SI=1 to old SGW. |
27 |
MME receives Delete Session Response. Call cleared in old SGW. |
28 |
GTPC-EP ingress receives Delete Bearer Command from MME for BearerContext to delete (EBI 6). |
29 |
SGW service POD receives Delete Bearer Command from GTPC-EP ingress. |
30 |
SGW service POD forwards Delete Bearer Command to GTPC-EP. |
31 |
GTPC-EP forwards Delete Bearer Command to PGW. |
32 |
PGW responds with Delete Bearer Request (EBI 6) to GTPC-EP. |
33 |
GTPC-EP sends Delete Bearer Request to SGW service POD. |
34 |
SGW service POD processes Delete Bearer Request and sends to GTPC-EP ingress. |
35 |
GTPC-EP ingress sends Delete Bearer request to MME. |
36 |
MME responds with the Delete Bearer Response to GTPC-EP ingress. |
37 |
GTPC-EP ingress receives Delete Bearer response and sends to SGW service POD. |
38 |
SGW service POD processes Delete Bearer Response and forwards to GTPC-EP. |
39 |
GTPC-EP forwards Delete Bearer Response to PGW. |