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Why PGW sends Downlink TFTs to UE?

+2 votes
153 views

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

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posted Jan 16, 2017 by Jim Tan

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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).

1 Answer

0 votes

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.

answer Jan 16, 2017 by Harshita
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.
Similar Questions
+1 vote

What are the modulation schemes used for the Downlink Channel in LTE?

+1 vote

Few doubts about TFT -
1. What is the role of TFT in LTE is it just limited at PGW or more then that.
2. How this is applied at PGW.

+2 votes

Hi Folks,

I am trying to create multiple dedicated bearers for UE with same tft set. Is it possible to have same tft set for multple dedicated bearers.?

The reason for asking this is I am actually facing a problem while creating multiple dedicated beares. As soon as second dedicated bearer established for UE, UE is sending Bearer Resource Modification with cause (Regular Deactivation). Couldn't able to find why it is happening.!

Please provide some suggestions..

Thanks.
Naveen.

0 votes

At what stage before a UE sends attach request, the DCI is seen in the downlink? I assume it's conveyed in the RRC, but not clear where to look for it in the RRC log. May be I'm not searching for the right keyword.

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