Question: In an IP Multimedia Subsystem (IMS), how does a Home Subscriber Server (HSS) typically initiate a response to alleviate its own overload situation, affecting communication with the I/S-CSCF?
Option 1: By sending a Diameter Credit-Control Request to the Online Charging System
Option 2: Through a SIP overload control mechanism directly to User Equipment (UE)
Option 3: Via an SMS notification to subscribers to reduce usage
Option 4: By requesting traffic reduction from the I/S-CSCF using an OC-OLR AVP in answer commands
Explanation: In IMS, when a Home Subscriber Server (HSS) detects an overload situation (e.g., high Cx interface traffic, CPU usage), it can proactively manage this by requesting the I/S-CSCF to reduce incoming traffic. This is achieved through including an Overload Control - Overload Reduction (OC-OLR) Attribute-Value Pair (AVP) in its answer commands, as per IETF standards for Diameter overload control. This mechanism allows for efficient network resource management without directly involving end-users or using less relevant protocols like SIP for this specific purpose.