1. Feature Guide
  2. DSR Features and Functions
  3. Topology Hiding
  4. S9 PCRF Topology Hiding

2.12.3 S9 PCRF Topology Hiding

S9 PCRF topology hiding is concerned with hiding the identity of a Protected Network’s PCRFs, as well as the number of PCRF’s in the network, when it exchanges messages with Untrusted Networks. A PCRF’s identity is embedded in the Origin-Host and Session-Id AVPs sent in Request messages and the Origin-Host AVP sent in Answer messages. This capability is associated with the Diameter S9 and Rx application messages over the S9Reference Point. This S9 PCRF Topology Hiding feature encompasses:

  • PCRF Topology Hiding in inbound and outbound roaming use cases – Hiding of PCRF host names in S9messages over the S9 Reference Point in Local Breakout (LBO) roaming architecture with the AF in the Visited Network or with the AF in the Home Network. Also hiding of PCRF host names in S9 messages over the S9Reference Point in the Home Routed Access roaming architecture.
  • PCRF Topology Hiding in outbound roaming use case: Hiding of PCRF host names in Rx messages over the S9Reference Point in Local Breakout (LBO) roaming architecture with the AF in the Visited Network.
  • PCRF Topology Hiding in inbound roaming use case – Hiding of PCRF host names in Rx messages over the S9Reference Point in Local Breakout (LBO) roaming architecture with the AF in the Visited Network where the Visited PCRF is implemented as a client/server of Rx messages to/from the Home PCRF.

The technique to hide and restore PCRF identities is similar to as described in S6a/S6d MME Topology Hiding.