Call Flows

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

Bearer Request/Response without UP Signaling Call Flow
Bearer Request/Response without UP Signaling Call Flow Description

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.