Reporting Load Information to SMF
The UPF sends its load control information to reflect the operating status of its resources at the node level. It allows the SMF to use this information to augment the UPF selection procedures. The load control information is piggybacked in PFCP request or response messages such that the exchange of load control information does not trigger extra signaling.
Considering the processing requirement of the receiver of the load control information, a larger variation in the Load Metric, example 5 or more units are reasonable value to send the new load control information.
The following criteria is used to send the Load Control Information IE:
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Whenever there is an increase or decrease in the load by 5% or more
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At 95% or above, LCI is reported for any increase
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At 5% or below, no LCI is reported
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At 100%, LCI is reported in all messages.
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System timestamp is used as Sequence Number.
NOTES:
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Currently, only session-load is considered to calculate Load Metric in the UPF.
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Multiple SessMgrs report same value of Load Metric with same sequence number.