Multicast Terminal IGMP Global Leave for Bandwidth Recovery
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Solution Overview
Problem
In multicast data transmission, when a user terminal becomes power off abnormally, it fails to send an IGMP Leave message, leading to continued data forwarding by multicast routers, resulting in bandwidth wastage and potential packet loss, as the router cannot initiate a real-time query to stop forwarding.
Innovation Solution
Implementing an IGMP Global Leave message mechanism where the user terminal notifies the multicast device upon startup to delete unwatched multicast groups, allowing the device to free up bandwidth by querying and deleting unused groups.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the multicast router uses periodic query to detect abandoned multicast groups, then the router can identify groups with no members, but there is a time delay in confirming no members exist in the sub-network
Solution Approach 1:
The system performs preliminary actions by having the terminal send an IGMP leave message before actually leaving the multicast group. This advance notification allows the router to prepare for group abandonment without waiting for the next periodic query cycle, thus reducing the time delay while maintaining detection accuracy.
Solution Approach 2:
The terminal provides feedback to the router by sending an IGMP leave message when it intends to leave the multicast group. This feedback mechanism enables the router to immediately know about the terminal's departure intention and stop forwarding data promptly, eliminating the waiting time inherent in periodic query methods.
2Productivity
If the host sends an IGMP Leave message to notify the multicast router, then the router can stop forwarding in real-time, but the method fails when the user terminal becomes power off abnormally and cannot notify initiatively
Solution Approach 1:
The terminal sends a global leave message as a preliminary action when it is about to power off abnormally. This message is sent before the terminal completely shuts down, ensuring the router is notified of the impending departure. The router receives this advance notice and can prepare to stop forwarding data, thus maintaining real-time stopping capability even under abnormal power off conditions.
Solution Approach 2:
The system provides beforehand cushioning by implementing a mechanism where the terminal attempts to send a global leave message before abnormal power off occurs. This cushioning measure ensures that even though the power off is abnormal, the router has been预先 notified and can gracefully stop forwarding data, preventing resource waste and maintaining system reliability.
3Device complexity
If the multicast router continues forwarding data to a terminal that has powered off abnormally, then no additional query mechanism is needed, but bandwidth is wasted and packet loss occurs
Solution Approach 1:
The terminal performs self-service by autonomously sending an IGMP global leave message when it powers off abnormally. This self-initiated notification eliminates the need for the router to implement complex detection mechanisms or continuous querying. The router simply receives the leave message and stops forwarding data, maintaining operational simplicity while preventing bandwidth wastage.
Solution Approach 2:
The terminal takes preliminary action by sending the global leave message before completely shutting down. This advance notification allows the router to stop forwarding data before the terminal is fully offline, preventing unnecessary bandwidth consumption and packet loss while keeping the router's operation simple and straightforward.
Data Source
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AI summary
A method and a system for processing abnormally becoming power off of a multicast user terminal are disclosed, and the method includes: a multicast device deletes multicast group(s) corresponding to the multicast user terminal and not watched by any multicast user terminal, upon receipt of a notification from the multicast user terminal for exiting all multicast groups when the multicast user terminal becomes powered off and started up again. Embodiments of the present invention can save bandwidth of a line effectively, and enable bandwidths of other services to be guaranteed better.