The present document investigates core network signalling overload scenarios and potential general handling solutions, in particular:

1. Identify and document events that have occurred and caused network disturbances due to signalling overload. In addition, identify and document scenarios that have high probability of occurrence in the 3GPP network, which may result in signalling overload for core network entities. Such scenarios/events may include HLR/HSS overload by RNC restart, denial of service attacks, and misbehaving/3GPP-non-compliant mobiles causing unpredictable system response;
2. Analyse the criticality of the scenarios and determine whether it is required to take actions for the identified scenarios;
3. Study ways to mitigate and/or eliminate the impact on the core network from signalling overload scenarios that are identified to be critical.

The information provided about the HSS/HLR overload will serve as a starting basis for the study. All currently deployed 3GPP networks should be covered in the study, including LTE The study should avoid overlap with other parallel activities within 3GPP, and work in close cooperation with the specific WG needs to be maintained. During the study, if potential security threats such as denial of service attack scenarios are identified, SA WG3 must then be informed to take appropriate measures.

The following documents contain provisions which, through reference in this text, constitute provisions of the present document.

• References are either specific (identified by date of publication, edition number, version number, etc.) or non specific.
• For a specific reference, subsequent revisions do not apply.
• For a non-specific reference, the latest version applies. In the case of a reference to a 3GPP document (including a GSM document), a non-specific reference implicitly refers to the latest version of that document in the same Release as the present document.