Why PGW sends Downlink TFTs to UE?

Question

Hi all

Downlink TFTs is used just for P-GW to decide which bearer that packet should go.
It is not useful for UE (or i miss something?)

Therefore, why PGW sends Downlink TFTs to UE?

thanks

**

Find the answer. The answer is include in comment.

**

Comments

I find the answer by myself, but the system here cannot post answer by questioner.
So i post the answer here down below.

---

In 23.401 4.7.2.1
The UE may use the UL TFT and DL TFT to associate EPS Bearer Activation or Modification procedures to an application and to traffic flow aggregates of the application. Therefore the PDN GW shall, in the Create Dedicated Bearer Request and the Update Bearer Request messages, provide all available traffic flow description information (e.g. source and destination IP address and port numbers and the protocol information).

Answer 1

For the uplink direction when different kinds of packets are generated by UE service application, TFT packet filters are required same as for DL traffic to map different kinds (QoS) packets to different radio bearers so that End to End QoS can be maintained in LTE network.

Comments

thanks for your reply. Do you mean that UE need to know what DL bearer that every packet goes, so UE can decide how to change QCI of DL bearer when UE needs? is there any spec mention about it?  thank you very much.