2.2 Understanding SoR Functionality

Different methods can be used within the roaming platform to control outbound roaming registration traffic. For each roaming partner providing service in a given country to the home network's outbound roamers, the home network can define static proportion of successful registrations.

The following factors are used to determine whether a request is accepted:

• Desired distribution of the registrations
• A subscriber that has successfully connected and registered through some vMNO should be allowed to keep on using this vMNO, even if the subscriber has changed location
• The number of registration attempts should be limited to some predefined value regardless of the distribution preferences of the home operator. After a maximum number of registration attempts, the subscriber should be allowed to register through any vMNO.

To distribute the registration requests in accordance to some distribution preferences and limit the number of rejections, the SoR application keeps the following types of data:

• Information about the distribution of registrations in the form of X registrations from MCC in country MCC
• Information about how often the registration attempt by a subscriber is rejected and through which MNO was the last successful registration of that subscriber

When a client attaches to the network of an operator (vPLMN), an Update Location Request (ULR) is generated that indicates the operator through which the subscriber is trying to register. The SoR application is deployed as part of the DSR logic. When receiving an ULR from a roaming subscriber, the SoR logic determines (based on a predefined profile) whether the request should be processed and forwarded to the HSS or rejected. If the ULR is rejected by SoR, then the subscriber initiates another registration and thus a new ULR, possibly through another operator.

ULR messages of the same subscriber can arrive through different vPLMNs and be processed by different DSR instances. This information is kept in a database that can be accessed by different DSR instances, such as the UDR. Thus, when the SoR application rejects or accepts a registration request, it also updates the subscriber information in the UDR.

The Home-MNO define roaming steering profile tables and includes the following:

• Country (MCC)
• The list of MNC values (one or more) that are owned by the visited-MNO
• Per Visited-MNO traffic rate
• Unique identification of a Visited-MNO (MNO-ID)
• A textual representation of the visited operator (V-MNO Name)
• Visited-MNO status (Preferred/Non-Preferred)

The SoR menu options allow you to:

• Perform SoR configuration tasks
• View information about SoR settings and tables
• Work with SoR provision tables