What is the role of diameter proxy agent?

Question

Please find the description of the problem:
A diameter client and server communicates in the network through Proxy Agent.
Here, I have assumed PCEF is a diameter client and PCRF is a diameter server. Interface between the PCEF and the PCRF is known as Gx.

Does Proxy agent, which sits between PCEF and PCRF, need to support Gx application ?
Does Proxy agent validate presence of any mandatory or optional AVP when it receives a message from a diamter client (PCEF) before forwarding it to diameter server (PCRF) ?

Can someone please provides the detailed behavior of a proxy agent ?

Answer 1

Diameter proxy agent is a diameter node which can modify a diameter message and its AVPs if some policies need to impose. A diameter proxy agent is also known as Diameter X agent where X denotes an application identifier. There are two other types of nodes are well known i.e. relay and re-direct nodes.

Answer 2

on behaf of Bart (https://www.facebook.com/groups/LTE.Professionals/ )

Proxy Agent, similarly to Relay Agent, can redirect messages using the Diameter Routing Table. The difference is that Proxy Agent can modify the message content and, therefore, provide value-added services, enforce rules or perform administrative tasks for a specific realm.