Multicast Packet Delivery in Wireless Non-Storing Networks
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Solution Overview
Problem
In wireless networks operating in non-storing mode, existing technologies face challenges in efficiently delivering multicast packets due to limited memory and power constraints, as only the root node has complete routing information, requiring each node to rely on it for packet forwarding, which is inefficient for multicast communications.
Innovation Solution
Router nodes maintain multicast information to identify child nodes registered for specific multicast addresses and unicast multicast packets at the L2 level to registered child nodes, reducing memory requirements and avoiding unnecessary broadcast overhead, while the root node handles registration requests and forwards packets only to registered devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multicast packets are delivered using traditional routing in non-storing mode, then routing information is centralized at the root node, but multicast delivery efficiency deteriorates due to excessive memory requirements and power consumption at intermediate nodes
Solution Approach 1:
The patent segments the multicast delivery function by distinguishing between unicast routing (handled by root node only in non-storing mode) and multicast group management (handled by intermediate nodes). Intermediate nodes maintain only local multicast group information rather than complete routing tables, dividing the information storage burden while maintaining delivery reliability.
Solution Approach 2:
Intermediate nodes maintain multicast information locally relevant to their immediate children rather than global routing information. Each node stores multicast group membership data specific to its local context, reducing memory requirements and power consumption while ensuring accurate delivery to registered devices through localized decision-making.
2Reliability
If intermediate nodes maintain complete routing information for multicast delivery, then packet delivery accuracy improves, but memory requirements increase significantly
Solution Approach 1:
Each intermediate node maintains only the multicast group information relevant to its local context - specifically, which of its child nodes are members of which multicast groups. This localized information storage ensures accurate packet delivery to registered devices while minimizing memory consumption by avoiding storage of global routing tables.
Solution Approach 2:
The patent extracts only the essential multicast group membership information from complete routing tables. Intermediate nodes store minimal data structures containing only the multicast addresses and corresponding child node identifiers needed for local forwarding decisions, discarding unnecessary global routing information.
3Reliability
If multicast packets are broadcast to all nodes, then delivery coverage is maximized, but network overhead increases due to unnecessary transmissions
Solution Approach 1:
The patent implements a feedback mechanism where intermediate nodes maintain state information about which child nodes are registered for which multicast groups. This feedback loop allows nodes to make informed forwarding decisions - packets are transmitted only to children that have expressed interest through registration, eliminating wasteful broadcasts to uninterested nodes while ensuring complete coverage of registered recipients.
Data Source
AI summary
A router node according to an aspect of the present disclosure maintains multicast information indicating child nodes registered for respective multicasts, while operating in a non-storing mode along with other router nodes of a wireless network for processing unicast packets. Upon receiving a layer-3 multicast packet, the router node examines the multicast information to identify a set of child nodes registered for the corresponding multicast. The router node thereafter unicasts, at L2-level, the layer-3 multicast packet to each child node of the set of child nodes. In an embodiment, the router node participates in a routing protocol (e.g., RPL) to form a hierarchy of nodes constituting the wireless network, with the hierarchy containing a root node and a set of end devices as leaf nodes.