Multicast Tree Calculation via Routing Control Plane
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Solution Overview
Problem
Existing multicast solutions in routed Ethernet mesh networks require significant forwarding state and complex computation, especially as the number of multicast instances increases, leading to inefficient use of network resources.
Innovation Solution
Advertise multicast group membership and specify algorithms for calculating multicast trees within the routing system, allowing nodes to determine the appropriate tree type (shortest path or spanning tree) and reduce forwarding state requirements by using algorithms like shortest path or spanning tree algorithms, which enable simpler computation and load distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If forwarding state is installed for each multicast source-group pair (S,G) to implement multicast connectivity, then multicast service coverage is improved, but forwarding state consumption increases significantly
Solution Approach 1:
The patent merges multiple source-group (S,G) forwarding states into a single group-based (*,G) forwarding state by implementing source-independent multicast forwarding. Nodes install forwarding state only for multicast group addresses rather than maintaining separate state for each source, thereby reducing forwarding state consumption while maintaining multicast service coverage through the algorithm specification mechanism.
Solution Approach 2:
The patent changes the forwarding state parameter from source-specific (S,G) to group-only (*,G) by introducing algorithm specifications that enable nodes to compute multicast trees without source-dependent state. This parameter change allows nodes to use less state-intensive tree constructs while still providing comprehensive multicast connectivity.
2Measurement precision
If complex multicast tree computation is performed for each multicast instance to ensure optimal routing, then routing precision is improved, but computational complexity increases
Solution Approach 1:
The patent implements a universal algorithm specification mechanism where nodes compute a single multicast tree using a specified algorithm (such as shortest path or spanning tree) that serves all multicast groups. This universal approach eliminates the need for separate complex computations for each multicast instance, reducing computational complexity while maintaining routing precision through the standardized algorithm application.
Solution Approach 2:
The patent performs preliminary algorithm specification and tree computation at the control plane before data plane forwarding. Nodes pre-compute multicast trees using the specified algorithm and install the resulting forwarding state, avoiding the need for complex real-time computation during actual multicast traffic forwarding. This preliminary action separates computation from forwarding, reducing operational complexity.
Data Source
AI summary
Interest in multicast group membership may be advertised via a routing system on an Ethernet network along with an indication of an algorithm to be used by the nodes on the network to calculate the distribution tree or trees for the multicast. Each node, upon receipt of the advertisement, will determine the algorithm that is to be used to produce the multicast tree and will use the algorithm to calculate whether it is on a path between nodes advertising common interest in the multicast. Example algorithms may include shortest path algorithms and spanning tree algorithms. This allows multicast membership to be managed via the routing control plane, while enabling spanning tree processes to be used to forward multicast traffic. Since spanning tree is able to install multicast state per service rather than per source per service, this reduces the amount of forwarding state required to implement multicasts on the routed Ethernet mesh network.