Diameter adoption and network geography

Diameter is used everywhere in the NGN core network – it is in the mobile, wireline, WiMax, Cable, from the ASN’s, GGSN’s and BRAS up to Application Servers. There isn’t a network core entity without at least Diameter interfaces, and some of them network functionalities have up to 4 different Diameter interfaces.
There are dozens of Diameter interfaces defined, over 110 interfaces are actually defined for Mobile, Wireline, Cable and WiMax and it seems also that the number is growing rapidly, new interfaces are introduced all the time, either for LTE (dozen of new interfaces), Lawful interception, interoperability, Roaming, IPTV, advanced policy and other needs.

But in reality most of those interfaces are still on the drawing boards or in the R&D labs, and not deployed and used yet in operators networks.
So what we see in the market, what places have the highest Diameter maturity, here is my view, top to bottom
I believe that the highest maturity is around the Charging and Billing systems ( what is called Rf, Ro, Gy, Gz, CCA interfaces)
It could be the connection from the Application to the Charging system, or from the GGSN to the Billing, or other network functionality, but it seems always to involve some charging component.
2nd place is given to the AAA servers and subscribers databases area, either HSS, NASS or other AAA Server, (interfaces like Sh, Dh, Cx, Dx), it could be CSCF connectivity to HSS, HSS to Application Server or one of many other scenarios of connecting to a AAA and subscriber databases using Diameter.
The 3rd place closely behind is taken by the policy and enforcement area. Policy is a spaghetti of Diameter with more than 9 Diameter interfaces (Gx, Rx, Gq, Gq’, Tx,Ty…) and we see almost any combination you can imagine of those policy related Diameter interfaces nd sometimes requests for all of them.

The rest of the network Diameter interfaces are defiantly behind, we see growing number of requests for almost all the 100+ defined interfaces, but they are still tailoring behind and you can find them today mainly in the vendors and operators labs and not in deployed operational networks.
Actually one of the emerging areas is the LTE related Diameter interfaces, although not finalized yet, and bearing a temporary name those Diameter interfaces are in high demand with strong interest by vendors starting to developing and testing LTE related equipment.