GSMA PRD IR.88 INTERWORKING – There are two situations in which interworking between SS7 MAP and Diameter are required for LTE Roaming and for similar 2G to 3G IMS roaming situations. The interworking details are specified in 3GPP 29.305.
Case 1 – The Visited network has not implemented LTE, IMS. In this case, the Edge Router must provide the mapping to the Gr functionality so that from the 2G/3G VPMN, the EPS HPMN “looks like” a GPRS network.
Case 2 – The Home network has not implemented LTE, IMS but the HLR has been upgraded to support LTE security parameters (KASME) via the Gr+ interface (Release 8 or later).
The D7G (Diameter SS7 Gateway) addresses both of these cases as described in IR.88. Mavenir provides bidirectional interworking between Gr or Gr+ and the Diameter S6a and S6d interfaces. This means that the Diameter interfaces can be in either the home or visited network with corresponding support for Gr, Gr+ interfaces via SS7 MAP.
The D7G solution is suitable for deployment on a Linux platform using either SIGTRAN or traditional TDM SS7 interfaces. It may be co-deployed on the same hardware as a Mavenir DSC under certain circumstances.