The Diameter base protocol as defined in the IETF RFC 3588 was designed to be extensible, It has been adopted by the 3GPP for most interfaces in the Evolved Packet Core (EPC) and extended to include new applications, commands and Attribute-Value Pair’s (AVP) as required by the specific interface, for example Gx to the Policy and Charging Rules Function (PCRF), S6a to the Home Subscriber Server (HSS) and Gy to the On-line Charging System (OCS).

The problem is that, even though 3GPP have given guidelines for how to extend Diameter, each working group is free to make their own decision and results in different styles of extending Diameter that need to be handled by a common Diameter stack.

Also there is the need to interwork EPC interfaces based on different 3GPP releases, different versions of the same release, different vendors “interpretation” of the same version of the same release and also vendor-specific extensions. How will operators buy equipment from different vendors, and make them work in light of these challenges?

By: Chris Knight