Label-Based Backup Path Activation in Transport Networks
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Solution Overview
Problem
Current restoration methods in transport networks are slow due to decentralized network management and require extensive reconfiguration activities in the control plane, leading to increased restoration times and reduced network availability.
Innovation Solution
A label-based restoration method that pre-configures backup paths using pre-defined tables and internal tandem connections, allowing for fast activation of backup paths without consuming transmission resources until needed, and reduces reconfiguration activities by using restoration groups and prioritization rules.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If pre-configured backup paths are established in the management plane before failure, then restoration capacity is prepared in advance, but signaling message exchange in the decentralized network management leads to slow restoration times in the range of at least some hundred milliseconds
Solution Approach 1:
The patent pre-configures backup paths and stores them in local backup tables at network elements before any failure occurs. When a failure is detected, the system performs a simple local table lookup and activation rather than exchanging signaling messages, achieving restoration in the range of a few milliseconds. This preliminary action eliminates the need for slow decentralized signaling during actual restoration events.
Solution Approach 2:
The patent extracts the restoration path calculation and configuration from the decentralized management plane and places it locally at each network element in the form of backup tables. This extraction eliminates the need for signaling message exchange between distributed management entities during restoration, reducing restoration time from hundreds of milliseconds to just a few milliseconds while maintaining pre-configured restoration capacity.
2Reliability
If backup paths are established before failure in transport networks, then restoration routes are pre-calculated, but by definition the full bandwidth requested by the path is consumed independent of whether traffic is transmitted over this path
Solution Approach 1:
The patent creates a virtual copy of the backup path configuration in local backup tables at network elements, rather than establishing actual physical connections. This virtual copy allows the network to prepare restoration routes without consuming real bandwidth resources. When needed, the backup path is activated by switching to the pre-configured route, ensuring restoration reliability without premature resource consumption.
Solution Approach 2:
The patent changes the state of backup paths from physically established (consuming bandwidth) to virtually configured (not consuming bandwidth). By storing restoration route information as data in local backup tables rather than as active connections, the system maintains the parameter of route availability while changing the bandwidth consumption parameter from high to zero until actual activation is needed.
3Adaptability or versatility
If decentralized network management exchanges signaling messages for backup path activation, then restoration paths can be dynamically established, but the interaction of decentralized network management is a relatively slow process leading to restoration times of at least some hundred milliseconds
Solution Approach 1:
The patent performs the complex restoration path calculation and configuration actions in advance, storing the results in local backup tables at each network element. When a failure occurs, the system only needs to perform a simple local table lookup and activation, eliminating the need for slow signaling message exchange. This preliminary action maintains adaptability through pre-calculated alternative routes while achieving restoration speeds in the range of a few milliseconds.
4Quantity of substance
If restoration mechanisms establish completely new paths through the network after failure, then spare capacity is used efficiently, but the masking of failure occurs at a lower speed typically in the range of a few seconds
Solution Approach 1:
The patent pre-calculates and stores backup paths in local backup tables before failures occur. When a failure is detected, the system immediately activates the pre-configured backup path by performing a local table lookup and switching, achieving restoration in the range of a few milliseconds. This eliminates the need to establish completely new paths after failure, maintaining efficient spare capacity utilization while dramatically reducing failure masking time from seconds to milliseconds.
Data Source
AI summary
Paths in a transport network are identified by labels (n1-n4, b1-b4) and more than one restoration resources that can be used for setting up a particular backup path form a restoration group. Backup tables (R1, R7) are provided, which define restoration groups per path labels (b1-b4), only, rather than individual restoration resources. Upon initial receipt of a path label (b1-b4), a network element (1-13) selects according to pre-determined rules a particular restoration resource from the restoration group defined in the backup table (R1-R7) for this backup path label.