Deterministic Multicast Path Establishment in LLNs
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Solution Overview
Problem
Deterministic networking in low power and lossy networks (LLNs) faces challenges such as lossy links, low bandwidth, and resource constraints, making it difficult to ensure simultaneous and precise delivery of data packets across multiple destinations.
Innovation Solution
The establishment of deterministic multicast paths using a multicast forwarding tree, where network devices are scheduled to deliver messages simultaneously by identifying a multicast routing graph that optimizes buffering in penultimate and parent nodes, ensuring messages are delivered to terminal destination devices at the same arrival time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If deterministic multicast paths are established in LLNs, then simultaneous delivery to multiple destinations is achieved, but resource constraints (bandwidth, memory, processing) make path establishment difficult
Solution Approach 1:
The patent pre-calculates and stores optimal multicast paths and timing information in routing tables before actual data transmission. The border router computes deterministic multicast paths ahead of time, considering network topology and link characteristics, so that when data needs to be transmitted, the path is already established and ready for immediate use, avoiding real-time computation overhead
Solution Approach 2:
The patent introduces border routers as intermediary devices that specialize in deterministic routing functions. These border routers act as mediators between the data source and terminal devices,集中化处理路径计算和转发控制, reducing the processing burden on resource-constrained terminal devices while ensuring deterministic delivery
2Manufacturing precision
If network devices buffer messages to achieve simultaneous arrival, then delivery synchronization is improved, but buffer memory requirements increase
Solution Approach 1:
The patent implements differential buffering strategies where different network devices buffer different amounts of data based on their specific positions in the multicast tree and their downstream destination requirements. Each device's buffer size and timing are locally optimized rather than uniformly applied, reducing total memory requirements while achieving synchronization
Solution Approach 2:
The system pre-calculates the exact buffering duration required at each network device to achieve simultaneous arrival at terminal devices. The routing table stores predetermined timing information that tells each device exactly how long to buffer before forwarding, eliminating the need for complex real-time buffer management and reducing overall memory requirements
3Reliability
If deterministic paths are established with precise timing, then packet delivery reliability is improved, but network device processing capability requirements increase
Solution Approach 1:
The patent pre-computes deterministic multicast paths and timing parameters before data transmission. The border router calculates optimal paths considering network topology, link characteristics, and device capabilities in advance, storing results in routing tables. This eliminates the need for complex real-time path computation and timing adjustment during actual data forwarding
Solution Approach 2:
The patent enables network devices to automatically forward packets according to pre-configured routing table entries without requiring complex real-time decision-making. Each device simply matches incoming packets against its routing table and forwards according to predetermined instructions, reducing processing requirements while maintaining deterministic delivery
4Productivity
If multicast forwarding trees are used for simultaneous delivery, then delivery speed is improved, but path establishment complexity increases
Solution Approach 1:
The patent pre-establishes multicast forwarding trees and computes optimal paths before actual data transmission. The border router performs comprehensive path calculation considering network topology and device capabilities in advance, storing results in routing tables that guide rapid packet forwarding without requiring complex real-time tree construction
Solution Approach 2:
The patent introduces border routers as intermediary devices that集中化处理 multicast tree construction and path computation. These border routers act as specialized mediators that handle the complex path establishment tasks, allowing terminal devices to simply forward packets according to predetermined routing instructions, reducing overall system complexity
Data Source
AI summary
In one embodiment, a method comprises identifying, by an apparatus in a deterministic network, a multicast forwarding tree comprising a single multicast source as a root of the multicast forwarding tree, a plurality of terminal destination devices as respective leaves of the multicast forwarding trees, and forwarding network devices configured for forwarding a message, transmitted by the root, to the terminal destination devices; and causing, by the apparatus, the forwarding network devices to deliver the message to each of the terminal destination devices simultaneously at a same arrival time.