Dynamic Per-Hop Bandwidth in Multi-Path Label Switched Paths
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Solution Overview
Problem
Current traffic engineering techniques in computer networks, such as MPLS, face challenges in efficiently managing bandwidth and quality of service due to fixed bandwidth constraints along label switched paths, leading to congestion and suboptimal network utilization.
Innovation Solution
The introduction of multi-path label switched paths (MP-LSP) with sub-label-switched paths that allow varying bandwidth constraints at each hop, enabling ingress routers to dynamically adjust bandwidth between sub-LSPs to match incoming and outgoing constraints, reducing the need for additional sub-LSPs and improving network resource allocation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If fixed bandwidth constraints are applied along label switched paths, then bandwidth management is simplified, but network utilization becomes suboptimal and congestion occurs
Solution Approach 1:
The patent segments the single LSP into multiple sub-LSPs (first sub-LSP and second sub-LSP) that share common path segments. This segmentation allows independent bandwidth constraint management for each sub-LSP while maintaining overall path efficiency, resolving the contradiction between simplified management and optimal utilization.
Solution Approach 2:
The patent implements dynamic bandwidth constraint adjustment by allowing different bandwidth constraints (first bandwidth constraint and second bandwidth constraint) for different sub-LSPs along the same path. This dynamic approach enables the system to adapt bandwidth allocation to actual traffic needs, improving network utilization while maintaining manageable complexity through structured constraint propagation.
2Productivity
If multiple sub-LSPs are created to handle varying bandwidth requirements, then network utilization improves, but the number of sub-LSPs and state maintenance increases
Solution Approach 1:
The patent merges common path segments into a shared resource that is dynamically allocated to multiple sub-LSPs. By allowing sub-LSPs to share common links with different bandwidth constraints, the system achieves optimal utilization without creating completely separate paths for each bandwidth requirement, thereby reducing the total number of sub-LSPs needed.
Solution Approach 2:
The patent makes path segments universal by enabling them to serve multiple sub-LSPs simultaneously with different bandwidth constraints. This multi-functionality allows a single physical path segment to fulfill multiple logical routing requirements, reducing the overall number of sub-LSPs and state maintenance while maintaining high network utilization.
3Ease of operation
If bandwidth constraints are propagated uniformly across all hops, then protocol simplicity is maintained, but flexible bandwidth allocation at specific hops is prevented
Solution Approach 1:
The patent applies local quality by allowing bandwidth constraints to vary at specific hops (first bandwidth constraint at first hop, second bandwidth constraint at second hop) while maintaining uniform constraint propagation mechanisms. This enables flexible bandwidth allocation at critical points in the network without complicating the overall protocol, as the constraint modification is localized to specific hops rather than requiring complex per-link negotiation.
Data Source
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AI summary
Techniques are described for varying a bandwidth constraint at one or more hops along a path of a sub-label-switched path (sub-LSP) of a multi-path label-switched path (MP-LSP). The techniques include computing, by an ingress router, a plurality of paths for a plurality of sub-LSPs of a MP-LSP and outputting, by the ingress router, for each path of the plurality of paths, a respective resource reservation request message to establish a respective sub-LSP of the plurality of sub-LSPs, each respective resource reservation request message including an indication of an explicit route, a tunnel identifier indicating the MP-LSP, an identifier for the respective sub-LSP, an indication of a per-hop bandwidth constraint that corresponds to a respective incoming per-hop bandwidth constraint of the plurality of incoming per-hop bandwidth constraints, and one or more instructions to modify the indication of the per-hop bandwidth constraint.