Mobile Station Roaming Number

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A Mobile Station Roaming Number (MSRN) is an E.164 defined telephone number used to route telephone calls in a mobile network from a GMSC (Gateway Mobile Switching Centre) to the target MSC (see Network Switching Subsystem). It can also be defined as a directory number temporarily assigned to a mobile for a mobile terminated call. A MSRN is assigned for every mobile terminated call, not only the calls where the terminating MS lives on a different MSC than the originating MS. Although this seems unnecessary since many vendors' VLR's are integrated with the MSC, the GSM specification indicates that the MSC and VLR (Visitor Location Register) do not need to reside on the same switch. They are considered two different nodes as they have their own routing addresses. i.e.the MSRN is one of the returned parameters into SRI_Response message. In particular the MSRN is used into an MNP scenario (in this case it can be modified as 'RgN + MSISDN').

The Mobile Subscriber Roaming Number (MSRN) is a temporarily telephone number assigned for a mobile terminating call. This number is needed by the home network to forward incoming calls for the mobile station to the network it visits. It is stored in the Home Location Register (HLR).

This number can be assigned by the visited network upon initial registration, or it can be assigned on a per call basis. In the latter case the number has to be requested by the home network (HLR) for each incoming call before it can forward the call to the visiting network.