Study on General Packet Radio Service (GPRS) Tunnelling Protocol for Control plane (GTP-C) overload control mechanisms
The present document investigates various aspects related to the support of the GTP-C signalling based load / overload control solution as specified in 3GPP TS 23.401 [2] and TS 23.060 [3], as also concluded in TR 23.843 [4], 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, clause 8.2.6 & clause 10.2 of the 3GPP TR 23.843 v1.0.0 [4].
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.