LTE: What messages are exchanged between PCEF and PCRF while establishing dedicated bearer for an UE ?

Question

Lets say we have a session-0 established for the UE (IPaddress1) for the default bearer. This is when the PGW send the CCRequest(cctype=initial and ccnum=0). Lets say "Policy1" is sent by PCRF in CCA. Does this initial CCRequest has the "Flowdescription" AVP in this ?

Now a dedicated bearer1 is established so CCRequest is sent with (ccrtype =modify and ccnum=1). Lets say PCRF assigns "Policy 2".

Now dedicated bearer 1 is deleted, then what does the PGW send to PCRF ?

Another question: As of now I am storing the list of PolicyRules in PCRF, based on IMSI (IPAddress)..i.e c++ map of IPAddress and PolicyRules. But when the dedicated bearer is removed how do i access the map ? (to find which Policy is deleted)

Answer 1

Hi Vikram,

When the PCEF includes the Bearer-Usage AVP required for the bearer within the CCR command during the IP-CAN
session establishment procedure, the PCRF shall provide the Bearer-Usage AVP back in the response with the
authorized usage.

For example, If the PCEF includes IMS_SIGNALLING within the Bearer-Usage AVP and the PCRF accepts that
default bearer is dedicated to IMS signalling, the PCRF shall include the IMS_SIGNALLING within the Bearer-Usage
AVP. In this case, the PCRF shall restrict the bearer to only be used for IMS signalling by applying the applicable QCI for IMS signalling.

Thanks,
Chinmoy

Comments

Thanks Chinmoy to share your knowledge.