Encoding Trigger Points in SIP Session Identifiers
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Solution Overview
Problem
In telecommunications networks, maintaining state information for SIP requests is challenging, especially when there is no longstanding assignment of a subscriber to a network routing node, leading to issues with processing Initial Filter Criteria (IFC) and handling scenarios like calling card applications where state information needs to be retained beyond the SIP transaction lifetime.
Innovation Solution
Encoding trigger points, including IFC, into a communication session identifier within request messages, allowing network routing nodes to transmit these encoded identifiers and manage state information dynamically, enabling efficient processing without relying on local storage and adhering to IMS specifications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If state information is retained for the duration of the SIP dialog, then calling card applications and other scenarios requiring long-term state retention work correctly, but network routing nodes must maintain state information beyond the SIP transaction lifetime, increasing memory usage and complexity
Solution Approach 1:
The patent extracts the trigger point information from the local state of network routing nodes and encodes it into the ODI token, which is then transmitted in route headers. This removes the need for network routing nodes to maintain long-term state information, as the trigger points are now carried within the message itself rather than stored externally.
Solution Approach 2:
The patent creates a copy of the trigger point information and embeds it within the ODI token. This encoded copy travels with the SIP request through the network, allowing any network routing node to process the request without needing to maintain persistent state, thereby reducing memory usage and system complexity.
2Adaptability or versatility
If each network routing node processes requests independently without maintaining state, then system scalability and load distribution improve, but IFC re-evaluation must be performed hop-by-hop, increasing processing time and complexity
Solution Approach 1:
The patent performs preliminary encoding of trigger points into the ODI token before the SIP request enters the network. This pre-processing allows subsequent network routing nodes to simply decode and evaluate the already-prepared trigger points, rather than performing complex IFC re-evaluation from scratch at each hop.
Solution Approach 2:
The ODI token acts as an intermediary that carries the encoded trigger point information through the network. It mediates between the original S-CSCF that created the trigger points and subsequent network routing nodes that need to evaluate them, enabling stateless processing while maintaining correct IFC evaluation.
3Quantity of substance
If state information lifetime is set to match SIP transaction lifetime, then memory usage is reduced, but application servers cannot properly handle scenarios where they need to send requests back after the transaction ends
Solution Approach 1:
The patent extracts the essential trigger point information from the persistent state and embeds it directly into the ODI token. This allows the state information to effectively travel with the request throughout its entire lifecycle, including when application servers send requests back after the original transaction has ended, without requiring network routing nodes to maintain long-term memory of the state.
Data Source
AI summary
Measures for use in processing data in a telecommunications network. A request message is received in relation to establishment of a communication session involving a given subscriber. Subscriber configuration data is received in relation to the establishment. The subscriber configuration data includes a set of one or more trigger points at which one or more application services should be invoked in relation to communication sessions for the given subscriber. At least one trigger point from the set of trigger points is encoded into an identifier for the communication session within the request message. The request message including the identifier for the communication session in which the at least one trigger point has been encoded is transmitted.