Delay Tolerant Network Routing Using Path Log Distribution
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Solution Overview
Problem
The existing delay tolerant network (DTN) routing method, such as PROPHET, limits path selection by only updating distribution probabilities based on adjacency to the destination node, failing to increase transport factors for nodes beyond direct neighbors.
Innovation Solution
A routing method that calculates distribution probabilities based on a log of end-to-end paths stored in a routing table, allowing nodes to select next hop nodes by broadcasting path request messages and using distribution probabilities from path response messages to forward data to destination nodes, even when there is no direct end-to-end reachability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If distribution probability is updated based on only adjacency to destination node, then path selection is simplified, but transport factor for nodes beyond direct neighbors is limited
Solution Approach 1:
The patent extends the distribution probability calculation from direct adjacency (1-hop) to multi-hop paths by incorporating path log information. This adds a dimensional aspect to the routing decision process, allowing nodes to consider not only immediate neighbors but also nodes reachable through intermediate hops, thereby increasing the transport factor without overly complicating the operation.
Solution Approach 2:
The patent pre-calculates and stores path log information in routing tables before actual data forwarding occurs. By maintaining historical path information and pre-computing distribution probabilities based on path logs, the system prepares routing decisions in advance, enabling nodes to make informed forwarding choices without complex real-time calculations.
2Productivity
If distribution probability is calculated using path log from routing table, then transport factor increases, but device complexity increases
Solution Approach 1:
The patent uses path log information that is copied from routing tables of intermediate nodes. Instead of each node independently performing complex path analysis, nodes utilize pre-collected path log data that has been propagated through the network, reducing the computational burden while maintaining accurate distribution probability calculations.
Solution Approach 2:
The patent implements a feedback mechanism where path log information is continuously updated and fed back into the distribution probability calculation. By incorporating historical path data that reflects actual network conditions, the system adapts its routing decisions based on observed performance, improving transport factor while using manageable complexity through iterative updates rather than complex one-time calculations.
Data Source
AI summary
A routing protocol unit (11) of each node (1) in a delay tolerant network calculates the probability of distribution to the destination node based on the log of end-to-end paths to the destination node from the past to the present registered in a routing table (12). A DTN forward unit (13) of a source node determines a next hop node to be used to forward forwarding data, based on the calculated distribution probability of each node with respect to the destination node.