Topology Hiding Types

Topology Hiding can be a Diameter application-specific or Diameter application-independent procedure.

Topology Hiding is Diameter application-specific if the rules apply only to a Diameter application-specific message set (such as S6a).
Topology Hiding is Diameter application-independent if the rules apply to any Diameter message (any Command Code).

The information to be hidden can be controlled based upon the following Topology Hiding types:

S6a/S6d Topology Hiding
S6a/S6d Topology Hiding is applied only to the S6a/S6d Command Codes defined in 3GPP TS 29.272, "Mobility Management Entity (MME) and Serving GPRS Support Node (SGSN) related interfaces based on Diameter protocol", and requires knowing which S6a/S6d messages are HSS-initiated versus MME/SGSN-initiated.
- S6a/S6d HSS Topology Hiding
  S6a/S6d HSS Topology Hiding is concerned with hiding the identity(s) of a Protected Network's HSS when it exchanges messages with Untrusted Networks. An HSS's Hostname is embedded in the Origin-Host and Session-Id AVPs sent in Request messages and in the Origin-Host AVP sent in Answer messages.
  
  S6a/S6d HSS Topology Hiding determines which entity (HSS or MME/SGSN) initiated a message, based on the Command Code in the message.
  
  S6a/S6d HSS Topology Hiding can be enabled for each Protected Network, by assigning an S6a/S6d HSS Topology Hiding Configuration Set to the configured Protected Network.
- MME/SGSN Topology Hiding
  MME/SGSN Topology Hiding is concerned with hiding the identity of a Protected Home Network's MME/SGSNs, as well as the number of MME/SGSNs in the network, when it exchanges messages with Untrusted Networks. A MME/SGSN's identity is embedded in the Origin-Host and Session-Id AVPs sent in Request messages and in the Origin-Host AVP sent in Answer messages.
  
  MME/SGSN Topology Hiding determines which entity (HSS or MME/SGSN) initiated an S6a/S6d message, based on the Command Code in the message.
  
  MME/SGSN Topology Hiding can be enabled for each Protected Network, by assigning an MME/SGSN Topology Hiding Configuration Set to the configured Protected Network.
S9 PCRF Topology Hiding
S9 PCRF Topology Hiding is concerned with hiding the host names of PCRF's in a Protected Network, as well as the number of PCRFs from Untrusted Networks.
Note: S9 PCRF topology hiding is only applied to the S9 and Rx command codes.
S9 AF/pCSCF Topology Hiding
S9 AF/pCSCF Topology Hiding is only applied to the Rx command codes when Visited Access Roaming Architecture is used and AF/pCSCF is communicating to H-PCRF in Proxy Mode. It allows the operator to hide the host names of AF/pCSCF's in a Protected Network as well as the number of AF/pCSCF's from Untrusted Networks.
Path Topology Hiding
Path Topology Hiding is Diameter application-independent, and can be applied to any Diameter Command Code.
Path Topology Hiding is concerned with hiding a Protected Network's Hostnames and the number of hosts in the following AVPs:
- Route-Record AVP: Sent in Request messages. More than one Route-Record AVP can exist in a Request message.
- Proxy-Host AVP: An AVP embedded in the grouped Proxy-Info AVP that is sent in Request and Answer messages. More than one Proxy-Host AVP can exist in a message.
- Error-Reporting-Host AVP: Sent in Answer messages. More than one Error-Reporting-Host AVP can exist in an Answer message.
Path Topology Hiding can be enabled for each Protected Network, by assigning a Path Topology Hiding Configuration Set to the configured Protected Network.