TFT filtering rule in LTE network

TFT

TFT is set of all packet filter associated with an EPS bearer. A packet filter may be associated with a protocol. A packet filter Identifier shall be used to identify a packet filter. For eg: lets say we have http traffic. Now we all know that destination port in Http is 80. So a packet filter can be created indicating destination port to 80 and this packet filter may associate with a ID which is nothing but packet filter ID. Now several packet filters can be combined to form a Traffic Flow Template.

One EPS bearer is established when UE connects to PDN and that remains lifetime of that PDN connection to provide UE with always on IP connectivity to PDN. This is default bearer. Any additional bearer that is established to the same PDN is referred as dedicated bearer.

Up Link Traffic Flow Template (UL TFT) : - Set of uplink packet filters in TFT
Downlink Traffic Flow Template (DL TFT) : - Set of downlink packet filters in TFT
Every dedicated EPS bearer is associated with TFT.

The following way we can define the TFT filtering rule for a bearer.

-       IP Network based

-       Port range base

-       Protocol base

-       Direction base

1. IP Network Base:

If each bearer will have distinct IP network then in this case the IP network base filtering can be used.

2. Port range Base:

If the network is same for the entire bearer then this can be used for TFT filtering.

3. Protocol Base:

This can be used to filter some protocol based TFT.

4. Direction Base:

This is a filtering rule for UL/DL direction.