SDN Switch Multicast Membership Maintenance via Local Query Filtering
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Solution Overview
Problem
In SDN networks, maintaining multicast group members is inefficient due to the high load on controllers from processing numerous query responses, especially when there are many members in a multicast group, as they periodically send and receive query messages to verify membership changes.
Innovation Solution
The controller sends query messages to a switch, which queries multicast group members and discards responses if a corresponding flow entry is found, reducing the need for the controller to process multiple responses. The controller also acquires count values from the switch to determine membership changes, allowing for efficient maintenance by using current and previous period values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the controller periodically sends general query messages to all multicast group members, then multicast group membership can be maintained, but the controller's processing load increases significantly when there are many members
Solution Approach 1:
The patent extracts the query response processing function from the controller and relocates it to the switch. The switch now handles querying multicast group members and processing their responses locally, while the controller only needs to send initial query messages and receive aggregated results. This extraction of the problematic processing function from the controller resolves the contradiction by maintaining membership reliability while improving controller productivity.
Solution Approach 2:
The switch acts as an intermediary between the controller and multicast group members. Instead of the controller directly communicating with all members, the switch mediates by receiving query messages from the controller, forwarding them to members, collecting responses, and returning aggregated results to the controller. This intermediary role reduces the controller's processing burden while maintaining the integrity of membership management.
2Measurement precision
If the controller processes all query responses from multicast group members, then accurate membership status can be determined, but the time consumed increases with the number of members
Solution Approach 1:
The patent merges multiple individual query responses from different multicast group members into a single aggregated response at the switch level. The switch combines the membership status information from all members and presents it as one consolidated result to the controller. This merging reduces the time the controller spends processing individual responses while maintaining accurate membership status determination through the aggregated data.
3Loss of information
If the switch forwards all query responses to the controller, then the controller has complete information, but unnecessary processing load is created when members do not change
Solution Approach 1:
The patent applies local quality by making the switch's response filtering behavior context-dependent. The switch examines each query response locally and determines whether to forward it to the controller based on whether actual membership changes are detected. When members remain unchanged, the switch filters out redundant responses locally. When changes occur, the switch forwards the relevant information. This local quality approach ensures information completeness is maintained only when necessary, while improving controller productivity by eliminating unnecessary data transmission.
Data Source
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AI summary
The present invention relates to the Internet field, and discloses a method and a device for maintaining a multicast group member. The method includes: sending a query message to a switch at intervals of a preset period, so that the switch sends the query message to each multicast group member included in a multicast group; acquiring a count value of current period query responses received by the switch in a current period; and maintaining, according to the count value of current period query responses and a count value of previous period query responses, the multicast group member included in the multicast group. The device includes: a first sending module, an acquiring module, and a maintenance module. In the present invention, a multicast group member is maintained by using a flow table maintained in a switch, which decreases load of a controller, and improves processing efficiency of maintaining, by the controller, the multicast group member.