The present document investigates various aspects related to the support of the GTP-C signalling based load / overload control solution as specified in TS 23.401 and TS 23.060, as also concluded in TR 23.843, with the main focus on:

• Definition of "Load Control" and "Overload Control" related information with enough precision to guarantee a common multi-vendor interpretation of this information allowing inter-operability between various GTP-C nodes;
• Mechanisms to address various "Notes", which are targeted to the stage 3, specified in clause 8.2.5 of TR 23.843, clause 8.2.6 of TR 23.843 and clause 10.2 of TR 23.843 v1.0.0.

This technical report addresses the following aspects related to the "GTP-C signalling based load and overload control" feature in detail:

• Investigation and study of the following aspects related to the "Load Control Information" to fulfill the normative requirements or to produce recommendations.
  • Definition of the "Load Control Information" by evaluating various parameters which can be exchanged under this information.
  • Inclusion of "Load Control Information" in GTP-C messages.
  • Potential enhancements to the existing node selection algorithm to take information received from "Load Control Information" into account.
• Investigation and study of the following aspects related to the "Overload Control Information" to fulfill the normative requirements or to produce recommendations.
  • Definition of the "Overload Control Information" by evaluating various parameters which can be exchanged under this information.
  • Inclusion of the "Overload Control Information" in GTP-C messages.
  • Message throttling algorithms and message prioritization when congestion mitigation is applied.
  • Propagation of the MME/SGSN identity to the PGW to ensure that the overload mitigation is always applied to the currently serving MME/SGSN.
  • Potential interactions with the existing overload control mechanisms when the overload factor is received within the "Overload Control Information".
• Investigation and study of the following the other deployment related aspects to fulfill the normative requirements or to produce recommendations.
  • Applicability of this feature to 3GPP and non-3GPP based GTP-C interfaces.
  • Methods to discover the support of this feature by the peer node in the network.
  • Supporting the feature across the PLMN boundary.
  • Issues within the network with partial support of this feature.
  • Overload mitigation policies when this feature support is not enabled in the network.