Hub-and-Spoke Routing Truncation Preventing Spoke Transit
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Solution Overview
Problem
In hub-and-spoke network topologies, existing methods fail to prevent spoke routers from being used as transit paths between hub routers, leading to potential network unreliability and packet dropages due to bandwidth limitations, especially when core links fail.
Innovation Solution
The method involves generating a link-state advertisement, computing a shortest path tree that excludes links from spoke to hub, creating a routing table based on this tree, and transmitting data packets accordingly, ensuring that spoke routers are not used as transit paths by truncating the tree at hub routers for such links.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If link state protocol computes shortest path tree including all available links, then routing flexibility is improved, but spoke routers are incorrectly used as transit paths causing network unreliability
Solution Approach 1:
The patent segments the shortest path tree computation by introducing a truncation mechanism that divides the routing decision process into two stages: first computing the complete shortest path tree using Dijkstra's algorithm, then selectively truncating paths that would transit through spoke routers. This segmentation allows the system to maintain routing flexibility for valid paths while preventing unreliable transit paths through spoke routers.
Solution Approach 2:
The patent extracts and removes the problematic transit paths through spoke routers from the shortest path tree. By identifying paths that traverse spoke routers and excluding them from the routing table, the system eliminates the reliability issue while preserving all valid routing options. This is achieved by modifying the path selection logic to reject any path containing spoke-to-spoke links.
2Ease of operation
If metric adjustment is used to prevent spoke transit, then routing control is improved, but device complexity increases due to manual configuration requirements
Solution Approach 1:
The patent implements a self-service mechanism where the routing protocol automatically identifies and prevents transit paths through spoke routers without requiring manual metric adjustment. The system autonomously computes the shortest path tree, detects paths traversing spoke routers, and excludes them from routing tables through programmatic logic, eliminating the need for manual configuration while maintaining precise routing control.
Solution Approach 2:
The patent performs preliminary action by pre-computing the shortest path tree and pre-identifying valid paths before actual data transmission occurs. The routing table is populated in advance with only acceptable paths, preventing spoke transit from the outset rather than requiring reactive metric adjustments. This preliminary path validation simplifies operation while maintaining control.
3Adaptability or versatility
If spoke routers are used as transit paths during core link failure, then routing redundancy is improved, but bandwidth limitations cause packet dropages
Solution Approach 1:
The patent applies preliminary anti-action by proactively preventing the use of spoke routers as transit paths even before core link failures occur. The routing protocol is configured to exclude spoke-to-spoke paths from the routing table in advance, anticipating that using these paths during failures would cause packet dropages due to bandwidth limitations. This preventive approach maintains routing redundancy through alternative hub-connected paths while avoiding the harmful effect of spoke transit.
4Reliability
If direct hub-to-hub link is required for reliable communication, then network reliability is improved, but device complexity increases and adaptability decreases
Solution Approach 1:
The patent introduces the hub router as an intermediary that mediates communication between spoke routers. Instead of requiring direct hub-to-hub links or allowing spoke-to-spoke paths, the system routes traffic through the hub as an intermediate node. The hub receives packets from one spoke, forwards them through the core network to another hub, and then to the destination spoke, ensuring reliable communication while maintaining the hub-and-spoke topology without requiring complex direct connections between all hubs.
Data Source
AI summary
In one embodiment, a method and apparatus of controlling transmission of data packets in a communications network includes designating all networking devices in a portion of the communications network as either hubs or spokes, communicating a link-state advertisement to each connected hub and spoke in the portion of the communications network, computing a shortest path tree at all the hubs and the spokes based on the link-state advertisement, the computing including truncating the shortest path tree at the hubs only for links leading from the spoke to the hub, creating a routing table at each of the hub and the spoke based on the truncated shortest path tree, and transmitting the data packets in the communications network based on the link-state advertisement. The shortest path tree includes all data transmission routes in the tree except links leading from a spoke to a hub.