What is the relation between DRA and IP CAN session and what is the IP CAN session and where it use in LTE and IMS?

Question

Can we have a live scenario wherein PCRF gets multiple attach request(CCR-I) where only the Framed-IP-Address and Session-Id are different but Subscriber-Id information and APN remain same? From network point of view, what can be the use case for this?

Answer 1

Diameter Routing Agent (DRA) can be used between any two Diameter nodes.
For example PCEF and PCRF in the context of LTE.
W.rt. LTE network, IP CAN session is established for an UE between PCEF and PCRF by exchanging the CCR and CCA messages.
In the context of IMS network, Diameter protocol is used between S-CSFF and HSS. Similarly, I-CSCF and HSS have Diameter based interface. It is not necessary all the nodes as mentioned above would be having direct connections . Diameter routing agent may be present in between.

Comments

Thank you very much, i got clear idea.

Answer 2

In between PCRF and PGW DRA could be present in different modes PA1, PA2 and Redirect DRA. You can get info on same in 29.213 spec