High Priority DDN Call Flow

This section describes High Priority DDN call flow.

High Priority DDN Call Flow
High Priority DDN Call Flow Description

Step

Description

1

Bearer received downlink data with ARP priority value as four, when UE is in IDLE state.

SGW-UP sends the Sx Report Request to the PFCP-EP with report type as DLDR with corresponding PDR ID.

2

New P-T1 transaction is started and routed the session report to all available service pods.

PFCP-EP sends the Sx Session Report Request to the SGW-service pod.

3

New S-T2 transaction is started and the SGW-service pod sends Sx Session Report Response to the PFCP-EP.

4

Transaction P-T1 and S-T2 completed and the PFCP-EP forwards the Sx Session Report Response to the SGW-UP.

5

New S-T3 transaction is started for which the DDN isn’t triggered.

SGW-service pod sends the DDN Request to the S11-GTP-EP.

6

New E-T4 transaction is started and the S11-GTP-EP forwards the DDN Request to the MME.

7

MME sends the DDN ACK success to the S11-GTP-EP.

8

Transaction E-T4 is completed.

S11-GTP-EP forwards the DDN ACK success to the SGW-service pod.

9

Transaction S-T3 completed.

SGW-service pod triggers No User Connect timer and updates session to CDL.

10

SGW-UP sends the Sx Session Report Request to the PFCP-EP with report type as DLDR for bearer whose ARP priority value is three.

11

New P-T5 transaction is started and routed the session report to all the available service pods.

PFCP-EP sends the Sx Session Report Request to the SGW-service pod.

12

New transaction S-T6 started

SGW-service pod sends the Sx Session Report Response to the PFCP-EP when bearer found as per the received PDR ID.

13

Transaction S-T6 and P-T5 completed and PFCP-EP forwards the Sx Session Report Response to the SGW-UP.

14

New transaction S-T7 started and data, high priority DDN sent with the flag value as False.

No User Connect timer is topped.

SGW-service pod sends the DDN Request to the S11-GTP-EP.

15

New E-T8 transaction is started and the S11-GTP-EP forwards the DDN Request to the MME.

16

MME sends the DDN ACK success to the S11-GTP-EP.

17

S11-GTP-EP forwards the DDN ACK success to the SGW-service pod for this PDR ID.

18

Transaction S-17 completed. SGW-service pod triggers the No User Connect timer when received DDN ACK success and updated the session to CDL.

19

Bearer received the downlink data with ARP priority value as two.

SGW-UP sends the Sx Report Request to the PFCP-EP with report type as DLDR with corresponding PDR ID.

20

New transaction P-T9 started and routed the session report to all the available service pods.

PFCP-EP sends the Sx Session Report Request to the SGW-service pod.

21

New transaction S-T10 started and the SGW-service pod sends the Sx Session Report Response to the PFCP-EP when the bearer found as per the received PDR ID.

22

Transaction S-T10 and P-T9 completed and the PFCP-EP forwards the Sx Session Report Response to the SGW-UP.

At SGW-service pod:

  • New transaction S-T11 started and data, high priority DDN sent with the flag value as True. SGW-service pod stops No User Connect timer.

  • SGW-service pod doesn't trigger DDN when high priority DDN already initiated. Transaction S-11 is completed.