Distributed Network Path Diversity via Intermediate Node Crankback
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Solution Overview
Problem
In distributed connection-oriented networks, ensuring absolute route diversity between connections originating from different source nodes is challenging due to the lack of information exchange between these nodes during path computation, particularly for Open-Open and Open-Close services.
Innovation Solution
The method involves signaling a first path from a first source node, storing call information at intermediate nodes, and checking for absolute route diversity when signaling a second path from a second source node. If a diversity violation is detected, a crankback mechanism is triggered, allowing the second source node to recompute the path exclusively based on the stored call information, ensuring maximal diversity without direct coordination between the connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If path computation is performed independently on different source nodes, then each source node can compute paths autonomously, but absolute route diversity cannot be ensured between connections from different source nodes
Solution Approach 1:
The patent introduces an intermediary mechanism where intermediate nodes store call information (path details, node identifiers, link identifiers) of established connections. When a new connection requires absolute route diversity, these intermediate nodes act as mediators to check the new path against stored information and detect diversity violations, enabling diversity verification without direct coordination between source nodes.
Solution Approach 2:
The patent implements a feedback mechanism through crankback signaling. When an intermediate node detects a diversity violation, it sends a crankback signal to the source node with information about the violation. This feedback enables the source node to adjust its path computation to ensure absolute route diversity, resolving the contradiction between autonomous computation and diversity assurance.
2Reliability
If intermediate nodes store call information for all connections, then diversity checking becomes possible, but network memory requirements and processing overhead increase
Solution Approach 1:
The patent applies local quality by having intermediate nodes store call information selectively rather than universally. Each intermediate node stores information only for connections passing through it, and only stores the essential elements needed for diversity checking (path identifiers, node identifiers, link identifiers). This localized, minimal storage approach enables diversity checking while limiting the increase in memory requirements and processing overhead to only what is necessary at each node.
Data Source
AI summary
A method in a network utilizing a distributed connection-oriented control plane includes signaling a first path for a first connection from a first source node; storing call information for the first connection at any intermediate nodes in the first path; signaling a second path for a second connection from a second source node; checking at any intermediate nodes in the second path if there is absolute route diversity between the first connection and the second connection responsive to a requirement therein; and responsive to detecting a diversity violation at an intermediate node of the any intermediate nodes in the second path, signaling a crankback to the second source node with the call information for the first connection included therein; and recomputing the second path exclusive of the first path based on the call information responsive to receiving the crankback. A network and node are also described.