Local Path Protection in Optical Networks Using Pre-configured Identification
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Solution Overview
Problem
Current optical networks face challenges in providing local path protection without a control plane, as they rely on distributed signaling protocols, which can lead to delays in communication between ingress nodes and centralized Path Computation Elements, impacting restoration times in case of failures.
Innovation Solution
Implementing a method for local path protection in optical networks using lambda-switching or time-division multiplex (TDM) switching, where identification information is used to forward signals on a shared alternative path, allowing for local protection decisions without a control plane, enabling efficient rerouting of optical signals based on pre-configured cross-connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If distributed signaling protocols are used for path protection in optical networks, then protection capability is provided, but communication delays between ingress nodes and centralized PCE impact restoration time
Solution Approach 1:
The patent pre-configures cross-connection information and identification information in nodes along the primary path before failures occur. When a failure happens, nodes can immediately switch to the pre-configured alternative path using local identification information without waiting for centralized PCE computation, thus reducing restoration time while maintaining protection capability
Solution Approach 2:
The patent extracts the control plane functions from the centralized PCE and implements local path protection decisions at individual nodes. Nodes independently make protection decisions based on pre-configured information and local failure detection, eliminating the need for time-consuming communication with the centralized controller
2Device complexity
If centralized PCE computation is used for alternative path routing, then path computation is centralized, but communication complexity and delays increase
Solution Approach 1:
Alternative path information and cross-connection details are pre-computed and configured in nodes before failures occur. This eliminates the need for real-time centralized computation and communication during failure events, reducing both complexity and delay
Solution Approach 2:
Nodes autonomously make path protection decisions using locally stored pre-configured information and identification data. Each node independently determines when to switch to alternative paths without requiring centralized control or inter-node signaling, simplifying the control plane architecture
3Ease of operation
If packet network FRR schemes are used with pre-configured forwarding tables, then local protection decisions can be made, but optical networks cannot add additional labels in the same manner
Solution Approach 1:
The patent uses identification information that copies the concept of label-based routing from packet networks. Instead of adding MPLS labels to optical signals, the system embeds identification data in optical overhead that serves the same function of identifying destination and routing decisions, adapting packet network FRR concepts to optical wavelength switching
Solution Approach 2:
The patent changes the parameter used for routing identification from packet labels to optical wavelength identification information. By modifying how routing information is represented and processed in the optical domain, the system achieves similar local protection capabilities without requiring label addition mechanisms incompatible with optical switching
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables fast and efficient local path protection in optical networks by eliminating the need for a control plane, reducing resource requirements and minimizing restoration time, while maintaining network resilience without the need for distributed signaling protocols.
Implementation Method 1
The signal is switched by lambda-switching or time-division multiplex TDM switching
Implementation Method 2
The signal is switched by lambda-switching or time-division multiplex TDM switching
Data Source
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AI summary
A method of local path protection in a node on a shared alternative path of a network (1). The method comprising receiving (201) a signal switched on a primary label switched path LSP. The signal is switched by lambda-switching or time-division multiplex TDM switching. The method further comprises receiving (203) identification information arranged to identify the signal,and forwarding (205) the signal on the alternative path based on the identification information.