SDN Midlay Segmentation for Slice Bandwidth Isolation
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Solution Overview
Problem
Current software-defined networking (SDN) implementations face challenges in efficiently managing bandwidth and resource allocation across network slices, leading to issues like incast and resource overutilization, as routing decisions are made in the underlay, preventing each overlay from having its own dedicated physical resources.
Innovation Solution
The introduction of midlays, which are intermediate layers formed by configuring subinterfaces with fixed bandwidths, allowing for dynamic allocation of bandwidth to network slices, effectively creating virtual underlays for overlays and enabling a Fat Tree-as-a-service model, where each slice can have dedicated resources and adjustable bandwidth based on requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a shared, flat CLOS/Fat-Tree model is used for SDN implementation, then device complexity is reduced and ease of operation is improved, but resource isolation is lost and incast/drops affect all slices
Solution Approach 1:
The patent divides the shared network into multiple isolated segments by creating separate underlays for each network slice. Each slice gets its own dedicated physical resources and routing infrastructure, preventing resource contention and incast issues from affecting other slices while maintaining manageable complexity through standardized segmentation procedures
Solution Approach 2:
The patent introduces a new architectural dimension by placing the underlay infrastructure below the overlay network slices. This dimensional separation allows each slice to operate independently with dedicated resources while the centralized controller manages all slices through this new hierarchical layer, resolving the conflict between simplicity and isolation
2Device complexity
If routing is decided in the underlay, then routing decisions are centralized and control is simplified, but physical resources cannot be associated with overlays and true slicing is prevented
Solution Approach 1:
The patent performs preliminary action by pre-establishing dedicated underlay infrastructures for each network slice before deploying overlay networks. This preliminary segmentation of physical resources enables true slicing capability while the centralized controller maintains simplified routing decisions within each isolated underlay, resolving the contradiction between complexity and adaptability
3Productivity
If overlays share a common underlay, then device complexity is reduced and resource utilization is improved, but bandwidth allocation cannot be isolated and performance of one slice affects others
Solution Approach 1:
The patent segments the shared physical infrastructure into multiple isolated underlay networks, each dedicated to a specific overlay slice. This segmentation enables bandwidth isolation where each slice guarantees performance without being affected by other slices, while the modular structure maintains efficient resource utilization through standardized deployment patterns
Data Source
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AI summary
In one embodiment, a device configures a plurality of subinterfaces for each of a plurality of physical ports of a software defined network (SDN). The device allocates a fixed amount of bandwidth to each of the subinterfaces. The device forms a plurality of midlays for the SDN by assigning subsets of the plurality of subinterfaces to each of the midlays. The device assigns a network slice to one or more of the midlays, based on a bandwidth requirement of the network slice.