Transport Network Restoration via Local Path Tags
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Solution Overview
Problem
Current restoration methods in transport networks are slow and require excessive spare resources, with restoration times ranging from several seconds to hundreds of milliseconds due to decentralized network management and the need for signaling messages across the entire network.
Innovation Solution
A method where each path is identified with a local identifier, such as a path tag, allowing network elements to pre-calculate and establish restoration paths without prior communication with the management plane, enabling faster and more flexible restoration by using locally available forwarding information to cross-connect traffic streams to alternate output ports.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If decentralized network management with local forwarding information is used, then restoration speed is improved, but network complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing restoration paths in forwarding information at network elements before failures occur. This allows immediate local decision-making during failures without waiting for centralized computation, significantly reducing restoration time while distributing the complexity burden across multiple elements rather than concentrating it centrally.
Solution Approach 2:
The patent segments the restoration function by distributing forwarding information locally at each network element, enabling independent restoration decisions at each segment. This segmentation eliminates the need for centralized coordination during failures, reducing overall restoration time while managing complexity through localized autonomy.
2Loss of time
If pre-calculated restoration paths are used, then restoration time is reduced, but resource consumption increases
Solution Approach 1:
The patent pre-calculates restoration paths and stores them in forwarding information at network elements. This preliminary action enables immediate local restoration decisions when failures occur, reducing restoration time to approximately 50 ms or less. The pre-stored forwarding information eliminates the need for real-time centralized computation, achieving fast restoration without requiring excessive spare resources.
3Stability of the object's composition
If centralized management plane signaling is used, then coordination is improved, but restoration speed deteriorates
Solution Approach 1:
The patent enables network elements to perform self-service restoration by using locally stored forwarding information to make independent restoration decisions. This eliminates the need for centralized signaling during failures, allowing immediate local action. The coordination function is maintained through pre-established forwarding information that ensures proper traffic routing without requiring real-time centralized control.
Solution Approach 2:
The patent applies preliminary action by pre-computing and storing restoration paths in forwarding information at network elements before failures occur. This allows network elements to autonomously execute restoration actions immediately when failures are detected, achieving fast restoration speeds while maintaining coordination through the pre-established forwarding information structure.
Data Source
AI summary
Transmission signals in a transport network are multiplexed from traffic streams respectively representing paths. Each path is identified with a path tag and forwarding information is provided in each network element. Failed paths in the network are restored in that the source network element crossconnects the affected traffic stream to an alternate output port and subsequent network elements receiving this unexpected traffic stream at an input port check the received path tag, determine an appropriate output port based on the tag and the forwarding information, and establish an internal cross-connection between the input port and corresponding output port.