HSS Overload Control via Severity Indicator
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Solution Overview
Problem
Current communication systems, such as the evolved packet system (EPS), lack effective overload protection mechanisms for the Home Subscriber Server (HSS), leading to service disruptions during high traffic conditions, such as simultaneous user registrations and resource allocation requests, without considering the severity of overload conditions.
Innovation Solution
Implementing a method to transmit an overload indicator with a severity indicator from the HSS to serving nodes, allowing them to adjust traffic volume and prioritize interfaces, and providing limited services until the overload condition is alleviated, including the use of 'congested mode' APNs and default profiles to reduce interaction with the HSS.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If overload control indication is implemented without severity information, then the HSS receives some protection from message flow restriction, but the serving nodes cannot differentiate between minor and severe overload conditions, leading to suboptimal traffic management
Solution Approach 1:
The patent introduces a severity indicator parameter that changes the state of the overload indication from a simple binary signal to a multi-level indicator. This allows serving nodes to differentiate between minor overload (first indicator value) and severe overload (second indicator value) conditions, enabling more granular traffic management and prioritization decisions without fundamentally changing the indication mechanism's structure
Solution Approach 2:
The overload condition is segmented into distinct severity levels (minor and severe) with different indicator values. This segmentation allows the system to handle different overload scenarios differently, applying appropriate traffic management strategies for each severity level rather than treating all overload conditions uniformly
2Ease of operation
If all user equipment continuously retry registration during overload, then users attempt to access services, but the HSS becomes overwhelmed with retry traffic, worsening the overload condition
Solution Approach 1:
The serving node receives feedback from the HSS in the form of an overload indication with severity indicator. Based on this feedback, the serving node adjusts user equipment behavior by preventing retries during severe overload conditions (when second indicator value is received) while allowing retries during minor overload conditions (when first indicator value is received). This feedback mechanism resolves the contradiction by making retry behavior adaptive to current HSS load conditions
Solution Approach 2:
The system dynamically adjusts retry behavior based on the received overload indication severity. When a second indicator value (severe overload) is received, the serving node configures user equipment to prevent retries. When a first indicator value (minor overload) is received, normal retry behavior is maintained. This dynamic adjustment allows the system to maintain ease of operation during minor overloads while protecting HSS stability during severe overloads
3Reliability
If the HSS processes all incoming traffic during overload, then service continuity is maintained, but the HSS may crash due to excessive load
Solution Approach 1:
During severe overload conditions (indicated by second indicator value), the system applies partial action by allowing only essential or high-priority traffic to reach the HSS while blocking non-essential traffic. The serving node prevents user equipment retries and may prioritize certain interfaces, allowing the HSS to process a reduced but critical subset of traffic that maintains essential service continuity without overwhelming the system
Solution Approach 2:
The serving node receives advance warning from the HSS through the overload indication mechanism before the HSS crashes. By receiving the second indicator value signaling severe overload, the serving node can proactively prevent further traffic from reaching the HSS, cushioning the system against complete failure and allowing the HSS to recover from the overload condition
Data Source
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AI summary
A method and apparatus can transmit communications traffic to a home subscriber server on a network. An overload indicator is received from the home subscriber server, with the overload indicator including a severity indicator. Traffic volume transmitted to the home subscriber server can be adjusted based upon the severity indicator.