Multicast Dictionary Compression for Reliable Point-to-Multipoint Delivery
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Solution Overview
Problem
In point-to-multipoint data communication systems, especially in satellite communications, existing methods for guaranteed delivery over multicast channels face challenges such as non-responding destinations causing channel capacity waste and unpredictable retransmission cycles, leading to inefficient bandwidth sizing and high operational costs.
Innovation Solution
The implementation of an Acknowledged Multicast data transfer mode, which uses multicast transmissions with acknowledgement sequences and block indices to manage data validity at destination nodes, allowing efficient data compression using Stream Compression techniques while avoiding unnecessary retransmissions and ensuring data integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multicast transmission is used for data transfer in P2MP systems, then data transmission efficiency is improved, but delivery reliability deteriorates due to lack of guaranteed delivery
Solution Approach 1:
The patent implements an acknowledged multicast mode where destination nodes send feedback messages to the source node to confirm successful reception of data blocks. This feedback mechanism allows the source node to track which blocks have been received and retransmit only those that were lost, thereby maintaining high transmission efficiency while ensuring reliable delivery.
Solution Approach 2:
The patent extracts the reliability guarantee mechanism from traditional unidirectional multicast by adding selective retransmission capabilities. Instead of relying solely on the multicast protocol's best-effort delivery, the system separates the data transmission function from the reliability function, implementing reliability through explicit acknowledgment and retransmission of lost blocks.
2Productivity
If compression dictionary is transmitted to all destination nodes, then data compression efficiency is improved, but channel capacity is consumed by dictionary transmission
Solution Approach 1:
The patent segments the compression dictionary into multiple data blocks that are transmitted separately to destination nodes. This segmentation allows for more flexible transmission and management of dictionary data, enabling the system to transmit only necessary portions and facilitating efficient storage and retrieval at the destination nodes.
Solution Approach 2:
The patent implements preliminary transmission of compression dictionary blocks to destination nodes before actual data compression begins. This preliminary action ensures that destination nodes have the necessary dictionary information stored and ready, enabling immediate compression of subsequent data transmissions without consuming additional channel capacity during the compression process itself.
3Reliability
If retransmission protocols are implemented for guaranteed delivery, then delivery reliability is improved, but system complexity and overhead traffic increase
Solution Approach 1:
The patent implements partial retransmission by sending acknowledgment messages that indicate specifically which data blocks have been successfully received and which need retransmission. Instead of retransmitting all data or using complex selective repeat protocols, the system performs only the necessary partial retransmission of lost blocks, reducing overhead and simplifying the protocol while maintaining reliability.
4Reliability
If multiple retransmission cycles are used to ensure all destinations receive data, then delivery completeness is improved, but bandwidth sizing becomes unpredictable and costly
Solution Approach 1:
The patent implements a self-service retransmission mechanism where individual destination nodes that fail to receive specific data blocks autonomously request retransmission of those blocks from the source node. This self-service approach allows the system to adapt to actual reception conditions, ensuring delivery completeness while minimizing unnecessary retransmissions and optimizing bandwidth utilization based on real-time needs.
Data Source
AI summary
Some applications that cannot operate over a non-reliable delivery service may operate sufficiently well over less than a completely guaranteed delivery service. Such an application may perform relatively well even if some transmitted data is not delivered, as long as the application has information regarding which receiving entities received what part of the data. In a point-to-multipoint system, data may be transmitted from a source node to a plurality of destination nodes using a plurality of multicast datagrams. Methods are presented herein for efficiently enabling the source node to determine for each of the plurality of destination nodes which multicast datagrams were successfully received. Also presented are methods for compressing data transmitted from the source node to the destination nodes, wherein a compression dictionary is transmitted from the source node to the destination node using multicast datagrams.