BIER Multicast Forwarding in SD-WAN Reduces Entry Convergence Time

The patent extracts the multicast distribution tree construction function from traditional PIM protocol and replaces it with BIER technology. Instead of establishing separate multicast distribution trees for each multicast flow, the patent uses BIER bit strings to directly identify destination nodes, eliminating the need for complex tree structures and reducing multicast entry convergence time while maintaining multicast service reliability

The patent changes the fundamental parameter of multicast routing from tree-based path identification to bit-string-based node identification. By using BIER bit strings where each bit position represents a destination node, the system transforms the complex multicast state information into compact binary representations, enabling faster convergence and reducing the quantity of multicast entries at each node device

The patent uses BIER bit strings as simplified copies of multicast destination information. Instead of storing complete multicast distribution tree structures and stream states, each node device stores compact BIER bit strings that represent the set of destination nodes. This copying approach reduces the quantity of multicast entries from complex tree structures to simple bit patterns, decreasing device complexity while preserving multicast service functionality

The patent inverts the traditional multicast routing approach by using destination-based bit string identification instead of source-based tree construction. Rather than building trees from the source and having nodes store stream states, the system uses BIER to directly encode destination sets, inverting the problem-solving approach and significantly reducing the number of entries needed at each node