Drop Port SRLG Assignment for Multi-Layer Network Diversity
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Solution Overview
Problem
In fiber-constrained optical networks, overlapping network types lead to single points of failure due to incomplete understanding of shared risk link group (SRLG) information, causing unpredictable failure modes and unidentified shared risks across different network layers.
Innovation Solution
Assigning SRLG details to drop ports instead of line ports, allowing for the sharing of SRLG information between network layers, enabling the control plane to consider these details when calculating paths and ensuring absolute route diversity across networks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If SRLG details are assigned to line ports, then network resource allocation is simplified, but shared risk identification between overlapping networks is incomplete
Solution Approach 1:
The patent segments SRLG assignment by introducing drop ports as a separate assignment target from line ports. By dividing the port types into line ports (for NNI connections) and drop ports (for fiber access points), the system can independently manage SRLG information at each interface type, enabling complete shared risk identification while maintaining manageable complexity through structured segmentation.
Solution Approach 2:
The patent adds a new dimension to SRLG management by introducing drop ports as an additional assignment target beyond line ports. This dimensional expansion from solely line-port-based SRLG assignment to both line-port and drop-port assignment enables the system to capture shared risks at fiber access points, improving reliability without fundamentally redesigning the existing SRLG framework.
2Productivity
If network types overlap in fiber-constrained environments, then network resource utilization is optimized, but single points of failure increase due to incomplete SRLG understanding
Solution Approach 1:
The patent makes the SRLG assignment mechanism universal by applying it to both line ports and drop ports. This multi-functional approach allows the same SRLG management framework to handle different network interfaces and overlapping network types uniformly, enabling complete shared risk identification across all network layers while maintaining optimized resource utilization.
Solution Approach 2:
The patent introduces drop ports as intermediary elements that mediate between fiber access points and network nodes. By assigning SRLG details to these intermediary drop ports, the system can propagate shared risk information through overlapping networks, enabling predictable failure mode analysis while preserving the resource optimization benefits of network type overlap.
3Device complexity
If control plane systems operate independently at different layers, then system complexity is reduced, but path diversity calculation across layers is impossible
Solution Approach 1:
The patent merges SRLG information from multiple control plane layers by propagating drop port SRLG details between layers. This combining approach allows independent control plane operations at each layer while enabling cross-layer path diversity calculation through the shared SRLG information propagated via drop ports, resolving the contradiction between simplicity and versatility.
Data Source
AI summary
Drop port based shared risk link group (SRLG) systems and methods assign SRLG information to drop ports in another level or layer of a network. Thus, drop side SRLG information can be shared between different networks or layers enabling a combination with line side SRLG information within a network to identify and prevent single points of failure across the networks. Typically, SRLG details are assigned to line ports (NNI ports) within a network and this information is not shared with external networks or network layers for routing a connection through the network and the external networks. By assigning SRLG details to a drop port, this information can be relayed between the network and the external networks and considered when planning a route through all of the networks.