Transit Network Node Intermediary Role for SIP Accounting

The patent introduces an intermediary accounting mechanism where the transit IMS network acts as a mediator in the accounting process. Instead of directly blocking accounting operations, the transit network inserts itself as an intermediate party that can properly handle and forward accounting information between the originating and terminating networks, thus resolving the contradiction between providing routing functionality and enabling reliable inter-operator accounting.

The patent creates a universal accounting framework that can accommodate different operator approaches while maintaining consistency. The solution defines a multi-functional accounting mechanism that works across different operator implementations, allowing each operator to maintain their preferred approach while ensuring that the overall accounting process remains consistent and reliable through standardized intermediary handling.

The patent segments the charging functionality from the core SIP session handling mechanism. Instead of complicating the basic SIP handling, it introduces separate, optional charging-related message elements and procedures that can be added when needed. This allows the core SIP mechanism to remain simple and easy to operate, while transit networks can implement charging functionality through the added segmented components.