Network Recovery Using Cross-Layer Resource Coordination
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Solution Overview
Problem
In optical networks with both IP and optical layers, network recovery from faults, such as optical fiber cuts, often fails due to lack of idle resources, leading to blocked IP links and congestion, potentially isolating parts of the network and disrupting IP services.
Innovation Solution
A method and apparatus that acquire network state and available resources to compute new optical and IP link path information, using idle and intact resources to establish new connections, ensuring network recovery by instructing nodes to set up new optical and IP links, thereby improving connectivity and reducing fault impact on other links.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If optical layer LSP performs recovery using protection switching or rerouting, then fault recovery is attempted, but recovery fails when no idle resource is available, leading to blocked IP links and network congestion
Solution Approach 1:
The patent transitions from single-layer recovery to multi-layer coordinated recovery by establishing correspondence between optical layer LSPs and IP layer links. When optical layer recovery fails due to resource constraints, the system utilizes intact resources in the IP layer to establish alternative paths, effectively adding a new dimension (IP layer) to the recovery process to overcome resource limitations in the optical layer.
Solution Approach 2:
The patent changes the recovery approach by computing new path information for both optical layer LSPs and corresponding IP links simultaneously. Instead of attempting recovery within the same layer, the system modifies the recovery parameters by allowing cross-layer resource utilization, where intact IP layer resources can compensate for depleted optical layer resources.
2Reliability
If traffic is redirected to other IP links during recovery, then alternative routing is achieved, but congestion occurs in other IP links
Solution Approach 1:
The patent computes new path information for both optical layer LSPs and IP links in advance before traffic redirection occurs. By pre-calculating alternative paths and establishing correspondence between layers, the system avoids abrupt traffic redirection that causes congestion. The preliminary computation ensures that alternative paths are identified and prepared before actual traffic flow changes.
Solution Approach 2:
The patent introduces a coordination mechanism between optical layer LSP recovery and IP layer link establishment as an intermediary process. This mediator computes and manages resource allocation across both layers, ensuring that traffic redirection is balanced and does not overload alternative IP links. The intermediary coordination prevents harmful congestion by regulating the recovery process.
3Device complexity
If single-layer recovery is used in optical layer, then recovery procedure is simple, but recovery fails when optical layer resources are exhausted, isolating network parts
Solution Approach 1:
The patent segments the recovery process into coordinated steps between optical layer and IP layer. Instead of a monolithic single-layer recovery, the system divides recovery into: (1) detecting optical layer fault, (2) attempting optical layer recovery, (3) if failed, utilizing intact IP layer resources to establish alternative paths. This segmentation maintains manageable complexity while improving reliability through cross-layer coordination.
Solution Approach 2:
The patent makes the recovery system multi-functional by enabling both optical layer and IP layer to participate in recovery operations. The system can perform optical layer protection switching, optical layer rerouting, and IP layer alternative path establishment depending on resource availability. This universality allows the recovery mechanism to adapt to different resource conditions while maintaining a unified recovery framework.
Data Source
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AI summary
Embodiments of the present invention disclose a network recovery method and apparatus. The method includes: when a fault occurs in an optical layer of a network, acquiring a network state and available resources in the network; where the available resources include idle resources in the optical layer and in an IP layer, and an intact resource in an optical layer LSP in which a fault occurs and an intact resource in an IP link corresponding to the LSP; according to the network state and by using the available resources, computing path information of a new optical layer LSP, a corresponding IP link, and configuration information corresponding to source and destination nodes of the IP link; instructing a source node of the new optical layer LSP to establish the optical layer LSP according to the path information of the new optical layer LSP; and after the optical layer LSP is successfully established, instructing the source and destination nodes of the IP link corresponding to the optical layer LSP to establish the IP link, and delivering, to the source and destination nodes, configuration information corresponding to them.