SIP Session Stuck Call Detection via RTP Probe
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Voice over Internet Protocol (VOIP) calls using Session Initiation Protocol (SIP) can become 'stuck' when one endpoint leaves the session without notification, leading to issues like media stream glitches and problems with reusing RTP destination ports, especially since many devices do not support session timers or intentionally disable them due to glitching issues.
Innovation Solution
Implementing a method where each participant in a SIP session uses timers to detect the absence of RTP/RTCP packets and sends probe messages only when no packets are received for a specified period, allowing the session to be cleared if no response is received, thus avoiding glitches and ensuring proper termination of sessions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If session timers are used to detect stuck calls, then call reliability is improved, but media stream glitches occur due to periodic interruption
Solution Approach 1:
The patent implements periodic probe messages (INVITE requests) to detect stuck calls, where probes are sent at intervals to check if the other endpoint is still active. This periodic detection mechanism allows the system to identify stuck calls without continuously interrupting the media stream, as probes are only sent when no media packets have been received for a specified duration.
Solution Approach 2:
The system uses the existing media packet flow itself as the detection mechanism. By monitoring whether media packets are received from the other endpoint, the system can detect stuck calls using the media stream's own characteristics rather than requiring separate detection protocols, thereby avoiding additional interruptions.
2Duration of action of stationary object
If session timers are disabled to avoid glitches, then media stream continuity is improved, but stuck call detection capability deteriorates
Solution Approach 1:
The patent establishes a predetermined threshold duration for media packet absence before triggering probe messages. This preliminary condition setup allows the system to wait for a specified period without receiving media packets before initiating detection, thereby avoiding unnecessary probes during temporary interruptions while still detecting actual stuck calls.
Solution Approach 2:
The system changes the detection parameter from continuous periodic probing (which causes glitches) to event-driven probing triggered only when media packet absence exceeds a threshold duration. This parameter change allows the system to maintain media stream continuity while still providing stuck call detection capability.
3Speed
If probes are sent frequently to detect stuck calls, then detection speed is improved, but network overhead and potential glitches increase
Solution Approach 1:
The patent applies partial action by sending probe messages only when necessary - specifically, when no media packets have been received for a predetermined duration. This avoids excessive probing during normal operation while ensuring detection occurs when actually needed, balancing detection speed with network overhead reduction.
Data Source
AI summary
A method and apparatus for terminating a communication session at a first communication device that had established a communication session with a second communication device in response to a determination that the first communication device has not received any media packets from the second communication device within at least one predetermined time period. In the event the first device determines that no media packets have been received from the second device within a first predetermined time period, a probe is sent to the second device. If a positive response is not received by the first device within a second predetermined time period from the sending of the probe, the first device terminates the session. If a positive response is received by the first device in response to the probe, the first device transmits additional probes during the session whenever media packets are not received from the second device within a third predetermined time period and the session is terminated by the first device if a response to the respective probe is not received within the second predetermined time period.