Multilayer Network Failure-Independent Link Provisioning
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Solution Overview
Problem
Multilayer networks face challenges in protecting against unknown network failures, such as fiber cuts and software bugs, where conventional over-provisioning is insufficient, as it is unclear where failures will occur, and thus, selecting independent working and protecting links is crucial to prevent network downtime.
Innovation Solution
The method involves configuring multiple links into mutually disjoint link groups, calculating paths that are as disjoint as possible, and dynamically modifying existing paths to ensure that new links are added to the network topology in a way that they are completely independent from existing paths, using MDLG identifiers and client layer routing protocols to advertise and evaluate links for failure independence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional network over-provisioning is used to protect against network failures, then network reliability is improved, but network complexity and resource waste increase
Solution Approach 1:
The patent segments the network into mutually disjoint link groups (MDLGs) where each group contains links that are topologically independent. By dividing links into these segments and assigning MDLG identifiers, the system achieves failure independence without requiring complete network over-provisioning, thus improving reliability while controlling complexity.
Solution Approach 2:
The patent introduces a new dimension of protection by calculating disjoint paths through the server layer for client layer links. Instead of simply adding redundant links at the same layer, it uses multi-layer topology to create protection paths that traverse different network dimensions, reducing resource waste while maintaining reliability.
2Reliability
If redundant links are added to protect against failures, then network reliability is improved, but bandwidth availability and resource efficiency deteriorate
Solution Approach 1:
The patent enables links to serve multiple functions by belonging to different MDLGs. A single link can provide protection for multiple other links across different MDLGs, allowing the same bandwidth resource to be universally utilized for protection purposes, thus improving reliability without proportionally increasing total bandwidth requirements.
Solution Approach 2:
The patent changes the topological parameters of protection paths by enforcing disjointness constraints. By modifying path selection to avoid shared links and nodes within MDLGs, the system achieves failure independence while optimizing bandwidth utilization, preventing unnecessary over-provisioning.
3Reliability
If working links and protecting links are selected to be completely independent, then failure independence is improved, but path calculation complexity and network configuration difficulty increase
Solution Approach 1:
The patent performs preliminary action by pre-calculating and assigning MDLG identifiers to links based on their topological relationships. This preliminary classification of links into disjoint groups simplifies subsequent path calculations, as the disjointness constraint is already encoded in the MDLG assignments, reducing real-time computational complexity.
Solution Approach 2:
The patent introduces MDLG identifiers as an intermediary mechanism that mediates between topological structure and path calculation. Instead of directly computing complex disjoint paths, the system uses MDLG labels as intermediaries to enforce failure independence, simplifying the path calculation process while maintaining reliability guarantees.
4Adaptability or versatility
If new links are dynamically added to the network topology, then network adaptability is improved, but maintaining failure independence and path disjointness becomes more difficult
Solution Approach 1:
The patent implements dynamic adaptability by allowing links to be added or removed from the network topology while maintaining MDLG assignments. When new links are introduced, the system dynamically evaluates their topological relationships with existing links and assigns appropriate MDLG identifiers, ensuring failure independence is maintained without requiring complete reconfiguration.
Solution Approach 2:
The patent uses feedback mechanisms to maintain failure independence during dynamic topology changes. When a new link is added, the system evaluates its path relationships with existing links and provides feedback on MDLG assignments, adjusting configurations as needed to preserve disjointness constraints and reliability guarantees.
Data Source
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AI summary
A method and apparatus for providing network failure independent links in a multilayer network comprising a client layer and a server layer, wherein each link of said client layer is served by a connection provisioned in said server layer,wherein mutually disjoint paths for said connections which serve links in said client layer that belong to the same predetermined mutually disjoint link group are calculated.