X2 Handover SGW Relocation to cnSGW-C Call Flow

This section describes the X2 handover SGW relocation to cnSGW-C call flow.

X2 Handover SGW Relocation to cnSGW-C Call Flow
X2 Handover SGW Relocation to cnSGW-C Call Flow Description

Step

Description

1

MME sends Create Session Request message to GTPC-EP ingress with the following:

  • OI flag set

  • MME Control TEID

  • PGW Control TEID

  • eNodeB Data TEID

  • PGW Data TEID

Establishes new transaction at GTPC-EP ingress.

2

SGW service POD receives Create Session Request.

3

SGW service POD Create a new transaction S-T1.

4

Validate Create Session Req.

5

NodeMgr allocates TEID.

SGW service POD reads the UPF cache and performs UPF selection.

6

PFCP-EP receives Sx Session Establishment Request from SGW service POD with the uplink and downlink Create PDRs/FARs (Apply Action as Forward)/CTEs.

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

Modify Bearer Request with updated S5 SGW Control TEID and S5 SGW Data TEID sent from the SGW service POD to GTPC-EP.

11

PGW receives Modify Bearer Request message from GTPC-EP.

12

GTCP-EP receives Modify Bearer Response from PGW.

13

SGW service POD receives Modify Bearer Response from GTPC-EP.

14

SGW service POD forwards Create Session Response to GTPC-EP ingress.

15

Updated session at CDL. Transaction S-T1 completed.

16

GTPC-EP ingress forwards Create Session Response to MME.

17

MME sends Delete Session Request with SI=1 to old SGW and receives Delete Session Response.

Call cleared in old SGW.