AVPs
Certain AVPs are applicable in only one direction, while others are applicable to both directions.
AVPs sent by the 7750 SR are used to:
- 
                inform the PCRF of the host creation/termination and the subscriber host identity in the 7750 SR 
- 
                inform the PCRF of the functionality supported in the 7750 SR 
- 
                report specific events related to the subscriber-host 
- 
                report the status of the rules 
- 
                report usage monitoring 
- 
                report status of the host (existent/non-existent) 
AVPs sent by PCRF toward the 7750 SR are used to:
- 
                install or activate policies 
- 
                request usage monitoring 
- 
                terminate the subscriber-host 
- 
                request status of the subscriber-host (existent/non-existent) 
AVPs that apply to both directions are used for base Diameter functionality such as peering establishment, routing of the Diameter messages, session identification and reporting of catastrophic failures (OSI change).