Section: 4.3.7.1a.1 GTP-C Load Control
Content: GTP-C Load Control feature is an optional feature which allows a GTP control plane node to send its Load Control Information to a peer GTP control plane node which the receiving GTP control plane peer node uses to augment existing GW selection procedure (i.e. as described in "PDN GW Selection" and "Serving GW Selection" according to clauses 4.3.8.1, and 4.3.8.2 respectively). Load Control Information reflects the operating status of the resources of the originating GTP control plane node. NOTE 1: How a node computes its Load Control Information is implementation dependent. Where certain pre-condition as described in clause 12.2.4.1 of TS 29.274[ 3GPP Evolved Packet System (EPS); Evolved General Packet Radio Service (GPRS) Tunnelling Protocol for Control plane (GTPv2-C); Stage 3 ]  [43], is applicable, an optional feature APN level load control may be supported and activated in the network. If this feature is activated, the PDN GW may convey the Load Control Information at APN level (reflecting the operating status of the resources at the APN level), besides at node level. GTP-C Load Control feature allows the Serving GW to send its Load Control Information to the MME/SGSN. GTP-C Load Control feature also allows the PDN GW to send its Load Control Information to the MME/SGSN via a Serving GW. Upon receiving Load Control Information the MME/SGSN supporting GTP-C Load Control feature uses it according to clauses 4.3.8.1, and 4.3.8.2 for "PDN GW Selection" and "Serving GW Selection" respectively. A node supporting GTP-C Load Control feature sends Load Control Information in any GTP control plane request or response message such that exchange of Load Control Information does not trigger extra signalling. A node supporting GTP-C Load Control feature sends Load Control Information to a peer GTP control node based on whether local configuration allows for it. A node supporting GTP-C Load Control feature may decide to send different values of Load Control Information on inter-network (roaming) and on intra-network (non-roaming) interfaces based on local configuration. Local configuration may allow the VPLMN to decide whether or not to act upon Load Control Information sent from a peer GTP control plane node in the HPLMN. NOTE 2: Refer to clause 12 of TS 29.274[ 3GPP Evolved Packet System (EPS); Evolved General Packet Radio Service (GPRS) Tunnelling Protocol for Control plane (GTPv2-C); Stage 3 ]  [43] for the details, such as exact format of the Load Control Information, mechanisms to discover the support of the feature by the peer node, interfaces for which this feature is applicable, APN level load control, etc.