LTE: What is the difference between PCC Rule and Packet Filter ?

Question

Depending on the packet filter, it is decided to which bearer does the incoming packet belongs to. If TFT does this job, then what is the use of Pcc-Rule ?

Is it that Pcc-Rules are not matched in case of dedicated bearers as in dedicated bearer packet filter are already matched ?
Is it that DPI is done only for default bearer packets and decided to which pcc-rule is belongs to ?

Please help with reference to spec...

Comments

On behalf of Venumadhav Josyula
In LTE UL ue/mobile terminal does tc (traffic classification). On p-gw,e DL side there is pcrf and pecf there is gx interface which uses pcc-rules. So the job of Tft and PC rules is different . One is for classification and other is pcrf charging and policy control. Even though they overlap they have different jobs.

Answer 1

Hi,

PCC rule includes Packet-Filter.

When we say PCC rule then it Packet-Filter is just a part of it. How Traffic shaping will happen depends on a lot of parameters.
Like QCI, ARP, and the QoS-Parameters MBR,GBR. Precedence plays a vital role in the packet filter treatment.

Eg : I have 5 filters in a particular session. Based on the precedence PGW will check if the packet matches the filter and then pass it towards SGW.
Also, there can be a possibility that you may have over-lapping filters. Now to which bearer the packet will go will be decided based on the precedence.

Check 29.212 for more information.

Regards,
Peeyush Sharma

Comments

Agreed with your answer, but where does the DPI come into picture ?

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DPI can be used to check the traffic based on the application like Http, IMS SIGNALLING, FTP, P2P traffic.
Like a particular type application can be allowed or blocked. It can also do the flow inspection based on the group of flows.
It can be integral part of PGW also.

Below link can help you in understanding the DPI functionality.
http://www.eetimes.com/document.asp?doc_id=1280856

DPI is not a mandatory part of PGW.
One use case can be that you want to allow only IMS Signalling through the default bearer and you do not have any filters applied on same.
This can be achieved through a DPI.

Regards,
Peeyush Sharma