Call Flows
This section describes the key call flow of Update Bearer Request and Response feature.

Step |
Description |
---|---|
1 |
MME sends Create Session Req to S11-GTP-EP with TEID value as zero. |
2 |
Transaction E-T1 started. S11-GTP-EP sends Create Session Req to SGW-Service POD. |
3, 4 |
Transaction S-T2 started. SGW-Service POD sends Allocate ID to Node-Mgr and receives response from it. |
5, 6, 7 |
SGW-Service POD reads Node-Mgr updated UPF cache and performs UPF selection. SGW-Service POD sends Sx Est Req to PFCP-EP. Transaction P-T3 started. SGW-Service POD receives Sx Est Rsp from PFCP-EP. |
8, 9 |
Transaction P-T3 completed. SGW-Service POD sends Create Session Req to S5-SGW-EGRESS-GTP-EP. Transaction E-T4 started. SGW-Service POD receives Create Session Rsp from S5-SGW-EGRESS-GTP-EP. |
10, 11, 12 |
Transaction E-T4 completed. SGW-Service POD sends Sx Mod Req to PFCP-EP. Transaction P-T5 started. SGW-Service POD receives Sx Mod Rsp from PFCP-EP. |
12 |
Transaction S-T2 ans P-T5 completed. SGW-Service POD sends Create Session Rsp to S11-GTP-EP. |
13 |
Transaction E-T1 completed. S11-GTP-EP sends Create Session Rsp to MME. |
14 |
SGW-Service POD sends Create Session to DB. |
15 |
MME sends Modify Bearer Req with TEID value to S11-GTP-EP. |
16 |
S11-GTP-EP routes MBReq with TEID to the exact SGW-Service POD. S11-GTP-EP sends Modify Bearer Request SGW-Service POD. |
17 |
Transaction S-T2 completed. SGW-Service POD sends Sx Mod Req to PFCP-EP. |
18 |
Transaction P-T3 started. SGW-Service POD receives Sx Mod Rsp from PFCP-EP. |
19 |
Transaction P-T3 completed. SGW-Service POD sends Sx Mod Rsp to S11-GTP-EP. |
20 |
Transaction S-T2 completed. SGW-Service POD sends Update Session to CDL. |
21 |
S5-SGW-EGRESS-GTP-EP sends Update Bearer request with TFTs and APN AMBR to SGW-Service POD. |
22, 23 |
Transaction S-T3 completed. SGW-Service POD sends Update Bearer Request to S11-GTP-EP. S11-GTP-EP forwards Update Bearer Request to MME. |
24, 25 |
MME sends Update Bearer Rsp to S11-GTP-EP. S11-GTP-EP forwards Update Bearer Rsp to SGW-Service POD. |
26 |
SGW-Service POD forwards Update Bearer Rsp to S5-SGW-EGRESS-GTP-EP. |
27 |
SGW-Service POD sends Update Session to CDL. |