SIP Session Refresh Using Reduced Header Messages
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Solution Overview
Problem
In VoIP networks, SIP messages often get lost due to unpredictable IP network delays and packet loss, leading to hanging sessions, and existing refresh mechanisms are costly and inefficient as they use bulky messages designed for other purposes.
Innovation Solution
Implementing a simplified refresh method using reduced SIP messages, such as reINVITE messages without SDP or XML bodies, for session refresh, and negotiating support for this method between refresher and refreshee to determine if a session is active, reducing processing time and bandwidth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional SIP refresh messages (reINVITE, UPDATE, OPTIONS) are used to refresh sessions, then session activity can be determined, but message size and processing overhead become excessively large
Solution Approach 1:
The patent extracts only the essential elements needed for session refresh (message type indicator, session identifier, timestamp) from the complete SIP message structure, eliminating unnecessary headers, bodies, and SDP information. This creates a minimal refresh message that retains functionality while dramatically reducing size.
Solution Approach 2:
The patent applies different message formats to different purposes: full SIP messages (reINVITE, UPDATE, OPTIONS) are used when complete session information is needed, while simplified refresh messages are used for routine session activity checks. This local differentiation optimizes each message type for its specific function.
2Adaptability or versatility
If full SIP messages with headers and bodies are sent for session refresh, then session parameters can be updated, but bandwidth consumption and processing time increase significantly
Solution Approach 1:
The patent removes unnecessary message components (full headers, SDP bodies, XML information) from refresh messages, keeping only the critical elements needed to verify session activity. This extraction reduces processing time while maintaining the ability to detect session state.
Solution Approach 2:
The patent sends minimal information (just enough to verify session activity) rather than complete session parameters during routine refreshes. Full parameter updates are reserved for when actually needed, reducing overall processing time while maintaining adaptability when required.
3Reliability
If reliable delivery protocols are used to prevent message loss, then hanging sessions are reduced, but network overhead and complexity increase
Solution Approach 1:
The patent implements periodic session refreshes using simplified messages at configured intervals. This periodic verification detects lost messages and hanging sessions without requiring complex real-time reliability mechanisms, balancing reliability with simplicity.
Solution Approach 2:
The patent uses response messages from refresh attempts to detect session status. If a refresh message is not acknowledged within a timeout period, the system infers the session may be hanging and takes appropriate action, providing reliable detection through simple feedback loops.
Data Source
AI summary
In one embodiment, a session is refreshed using a message that is simplified for refresh purposes. The refresh message that is used is a message used for another purpose in a protocol (e.g., SIP). For example, a reINVITE message may be used as a refresh message. If the reINVITE message is used for its intended purpose, the reINVITE message may be used to change the characteristics of a session. This reINVITE message includes an SDP and full header such that the parameters can be properly changed. However, the reINVITE message may be used to refresh a session. This may be referred to as a simple refresh message. But, the simple refresh message does not include an SDP or any other message body. The simple refresh message includes only a reduced header. This reduces time spent building and parsing the simple refresh message.