Lawful Intercept Target Provisioning in IMS Networks
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Solution Overview
Problem
Current IP Multi-media Subsystem (IMS) networks face challenges in efficiently provisioning target-related information for lawful intercept due to the lack of standardized interfaces between Lawful Intercept Server (LIS) and Call Session Control Function (CSCF) components, leading to increased development and maintenance costs and complexity in managing multiple interfaces.
Innovation Solution
A method is introduced where the LIS provides a target list containing information about surveillance targets to a Home Subscriber Server (HSS), which then distributes this list to logically attached CSCFs, using existing Diameter Dh and Sh interfaces, simplifying the deployment and management of lawful intercept functionality by reducing the number of interfaces and allowing CSCFs to be moved without reconfiguration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the LIS interfaces directly with each CSCF to provision target information, then complete target lists are available at each CSCF, but the number of interfaces to manage increases significantly and development/maintenance costs become significant
Solution Approach 1:
The patent introduces the HSS as an intermediary component between the LIS and multiple CSCFs. The HSS receives target information from the LIS and distributes it to attached CSCFs, eliminating the need for the LIS to maintain separate interfaces with each CSCF. This mediator approach reduces the number of interfaces while ensuring target information availability at all necessary CSCFs.
2Adaptability or versatility
If the LIS provisions complete target lists to each CSCF, then all CSCFs have access to all targets, but the complexity of adding or removing CSCFs increases due to required LIS reconfiguration and testing
Solution Approach 1:
The patent segments the target provisioning architecture by introducing the HSS as a centralized provisioning point. Instead of provisioning each CSCF individually from the LIS, the system divides the provisioning path into two segments: LIS to HSS, and HSS to individual CSCFs. This segmentation allows CSCFs to be added or removed without requiring LIS reconfiguration, as the HSS handles all provisioning operations independently.
3Adaptability or versatility
If proprietary interfaces are designed by each CSCF vendor for LIS communication, then each vendor can optimize their interface design, but multi-vendor implementation costs and maintenance complexity increase significantly
Solution Approach 1:
The patent makes the HSS a universal provisioning point that all CSCFs from different vendors can connect to using standardized interfaces. Instead of requiring the LIS to implement multiple proprietary interfaces for different vendors, the system uses a single universal HSS interface that all CSCFs can access, thereby reducing implementation costs and simplifying multi-vendor deployments while still allowing vendor-specific optimizations at the CSCF-HSS interface level.
Data Source
AI summary
Provisioning of target related information into an IP Multi-media Subsystem (IMS) communications network, to provide lawful intercept, utilizes an interface between a lawful intercept server (LIS) and one or more of the Home Subscriber Servers (HSSs) of the network. The LIS provisions an HSS with target information for LI, with respect to a subset of the overall list of LI targets, that is to say with respect to those of targets homed on the respective HSS. The HSS provisions the target list for its subset down to Call Session Control Function elements (CSCFs) logically attached to that HSS, to enable each CSCF to intercept signaling messages relating to communication for identified target user equipment (UE) devices. The intercepted signaling enables the LIS to identify a location of a target UE device in an access network and instruct a network control point to intercept content of communications for that UE device.