IMS Capacity Management via Pre-Routing Server Load Checks
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Solution Overview
Problem
IMS networks face challenges in managing capacity effectively, leading to unnecessary resource utilization and call rejections due to overloaded terminating servers, as existing systems reject calls only after reaching capacity, wasting resources and processing power.
Innovation Solution
Implementing a Usage and Capacity Control Server (UCCS) that identifies terminating VoIP call servers and returns a call rejection indicator without sending a request to overloaded servers, allowing for proactive admission control decisions based on server workload and resource utilization, thereby reducing unnecessary resource usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the terminating server rejects calls only after reaching capacity, then the server can handle maximum load, but unnecessary resources and processing power are wasted
Solution Approach 1:
The system performs preliminary capacity checking at the I-CSCF server before calls are routed to terminating servers. The I-CSCF queries the Home Subscriber Server (HSS) to determine if the terminating server has available capacity, and only routes calls to servers that can accept them. This preliminary action prevents wasted processing power on calls that would be rejected anyway.
Solution Approach 2:
The HSS maintains real-time capacity information for terminating servers and provides feedback to the I-CSCF. When a terminating server reaches its capacity threshold, the HSS updates its records, and subsequent call routing decisions are based on this feedback, directing new calls to alternative servers with available capacity instead of overloading the current server.
2Ease of operation
If calls are routed to overloaded servers, then routing simplicity is maintained, but call rejection rates increase
Solution Approach 1:
The I-CSCF server acts as an intermediary between the calling party and terminating servers. It queries the HSS to obtain capacity information and makes intelligent routing decisions, selecting appropriate terminating servers based on their current load. This intermediary function maintains routing simplicity while improving call acceptance rates by avoiding overloaded servers.
Solution Approach 2:
The system performs preliminary capacity verification through HSS queries before final call routing. This advance check ensures that calls are only routed to servers that can accept them, thereby maintaining high call acceptance rates without significantly complicating the routing process.
3Productivity
If capacity monitoring is implemented, then resource utilization is optimized, but system complexity increases
Solution Approach 1:
The HSS automatically maintains capacity information for terminating servers and makes this information available to I-CSCF servers on demand. The system serves itself by having the HSS, which already stores subscriber information, also track and provide capacity status without requiring separate complex monitoring infrastructure.
Solution Approach 2:
The HSS performs multiple functions: it stores subscriber information, manages authentication, and now also tracks terminating server capacity. By making the HSS multi-functional, the system avoids adding separate dedicated capacity monitoring systems, thereby optimizing resource utilization without significantly increasing overall system complexity.
Data Source
AI summary
Methods and apparatus to manage Internet Protocol (IP) Multimedia Subsystem (IMS) network capacity are disclosed. An example method comprises identifying a terminating voice over Internet protocol (VoIP) call server associated with a called device, and returning a call rejection indicator when the terminating VoIP call server is in a first condition, the call rejection indicator returned without a call initiation request message sent to the terminating VoIP call server.