Multicast Communication Device Hybrid IGP TE Route Control
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Solution Overview
Problem
Current multicast transfer systems, such as PIM-SSM and BIER-TE, face challenges in flexibility and scalability, particularly in large-scale networks, where route control and traffic management become complex due to the need for extensive route information and potential delays in fault recovery.
Innovation Solution
A communication device that employs a hybrid approach combining IGP and TE routes, allowing for flexible traffic control by prioritizing transfers to specified interfaces and destinations, reducing the need for comprehensive route allocation and enabling high-speed fault recovery by using bypass routes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If PIM-SSM is used for multicast transfer, then IP multicast transfer can be achieved in large-scale networks, but route flexibility is limited because the passing route is determined by IGP route calculation
Solution Approach 1:
The patent segments the routing control into two independent parts: IGP routes for basic connectivity and TE routes for service-specific optimization. This allows multicast transfer to use TE routes for flexible distribution tree specification while relying on IGP routes for underlying connectivity, thereby improving route flexibility without overwhelming device complexity
Solution Approach 2:
The patent introduces TE routes as an intermediary layer between the application layer multicast requirements and the network layer IGP routing. This intermediary enables service characteristic-based route optimization without directly modifying the IGP protocol, achieving route flexibility while maintaining manageable device complexity
2Reliability
If all devices on the join message passing route hold route information for each registration channel, then complete route information is available, but device load increases when the number of registration channels rapidly increases
Solution Approach 1:
The patent applies local quality by having devices hold only the route information they need for their specific function. Edge routers hold detailed registration channel route information, while relay devices hold only TE route information for efficient packet forwarding. This distribution reduces device load while maintaining route information completeness where needed
3Reliability
If IGP route switching is performed after fault detection, then route convergence is achieved, but communication recovery time increases due to join message retransmission delay
Solution Approach 1:
The patent prepares bypass routes in advance for potential failures. When a fault occurs, the system can immediately switch to the pre-calculated bypass route without waiting for IGP convergence and join message retransmission. This preliminary preparation significantly reduces communication recovery time while maintaining fault recovery capability
Data Source
AI summary
There is provided route control with excellent flexibility even in a large-scale multicast transfer system. A multicast transfer system transfers a multicast packet arriving at a plurality of destinations between multicast communication devices 1, and a packet transfer processing unit 15 of the multicast communication device 1 transfers, when an interface of a multicast communication device 1 adjacent to itself is specified as a transfer destination of a received multicast packet, the multicast packet to the specified interface, and transfers, when the interface of the multicast communication device 1 adjacent to itself is not specified as the transfer destination of the received multicast packet, the multicast packet to an interface to a multicast communication device 1 specified as the destination.