Section: 12.3.3 Node level overload control
Content: Node level overload control refers to advertising of the overload information at node level, i.e. overload information at node level granularity, and applying the mitigation policies towards the target node based on this information. This helps in preventing severe overload and hence potential breakdown of the GTP-C node. When a GTP-C entity determines that the offered incoming signalling traffic is growing (or is about to grow) beyond its nominal capacity, it may signal an Overload Control Information IE to instruct its GTP-C peers to reduce the offered load accordingly. Overload Control is performed independently for each direction between two GTP-C entities. Overload Control may run concurrently, but independently, for each direction between the two GTP-C entities. Overload control of SGW originated traffic towards the MME/S4-SGSN shall rely on Downlink Data Notification throttling, as specified in clause 4.3.7.4.1a of 3GPP TS 23.401[ General Packet Radio Service (GPRS) enhancements for Evolved Universal Terrestrial Radio Access Network (E-UTRAN) access ]  [3] and 5.3.6.5 of 3GPP TS 23.060[ General Packet Radio Service (GPRS); Service description; Stage 2 ]  [35], with the addition that the SGWs should be allowed, by configuration, to throttle DDN requests for low priority, as well as normal priority traffic (the SGW shall then throttle by priority DDN requests for low priority traffic).