DSTE Compliant MPLS Fast Reroute Backup Path Selection
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Solution Overview
Problem
Current MPLS Fast Reroute techniques lack the ability to select Facility Bypass tunnels that are compliant with specified DiffServ Traffic Engineering (DSTE) Class Types, leading to inadequate traffic handling during failures, as they do not ensure that backup paths maintain the same DSTE Class Type as the primary paths.
Innovation Solution
Incorporating the DSTE Class Type into the FAST_REROUTE object in MPLS signaling messages, allowing Label Edge Routers and Point of Local Repair nodes to select Facility Bypass tunnels that support the specified DSTE Class Type, ensuring that traffic is routed through tunnels with matching bandwidth constraints during failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional Fast Reroute techniques are used to provide backup paths, then fast traffic recovery is achieved, but the backup paths do not maintain the specified DSTE Class Type, leading to inadequate traffic handling
Solution Approach 1:
The patent applies preliminary action by incorporating the DSTE Class Type information into the FAST_REROUTE object during the path setup phase. This allows the PLR node to pre-identify and select backup paths that comply with the required DSTE Class Type before any failure occurs, ensuring both fast recovery and service quality maintenance when switching to backup paths
Solution Approach 2:
The patent implements feedback by using the DSTE Class Type information carried in the FAST_REROUTE object to guide the PLR node's selection of backup paths. The PLR node uses this feedback information to filter and choose only those backup paths that match the required service characteristics, ensuring compliant traffic handling during failure scenarios
2Adaptability or versatility
If DSTE Class Type information is incorporated into FAST_REROUTE objects, then backup path selection compliance is improved, but signaling message complexity increases
Solution Approach 1:
The patent applies universality by extending the existing FAST_REROUTE object to serve multiple functions: it continues to provide fast reroute capabilities while simultaneously carrying DSTE Class Type information for service-compliant path selection. This multi-functionality approach avoids creating entirely new signaling objects, thereby limiting the increase in signaling complexity
Solution Approach 2:
The patent applies the nested doll principle by embedding the DSTE Class Type information within the existing FAST_REROUTE object structure. Rather than adding external or separate signaling elements, the additional information is nested inside the already-established message framework, minimizing the impact on overall signaling complexity
3Speed
If Facility Bypass tunnels are selected without DSTE Class Type consideration, then path selection speed is maintained, but service quality during failures deteriorates
Solution Approach 1:
The patent applies preliminary action by pre-populating the FAST_REROUTE object with DSTE Class Type information during the initial path setup. When a failure occurs, the PLR node can immediately use this pre-provided information to filter and select compliant backup paths without requiring additional signaling or complex real-time decisions, thus maintaining fast switching while ensuring service quality
Solution Approach 2:
The patent applies parameter changes by modifying the path selection criterion to include DSTE Class Type matching. The PLR node changes the selection parameter from purely topological (fastest available path) to a combined parameter set that includes both speed and service class compliance, ensuring that the selected backup path meets both performance and service quality requirements
Data Source
AI summary
A Point of Local Repair (PLR) network element includes one or more ports and circuitry connected thereto for forwarding and control, wherein the circuitry is configured to receive a PATH message for a Label Switched Path (LSP) tunnel in a Multiprotocol Label Switching (MPLS) network with a specified DiffSery Traffic Engineering (DSTE) Class Type, determine the DSTE Class Type based on the PATH message, and store the DSTE Class Type for the LSP tunnel to ensure a Facility Bypass tunnel used for the LSP tunnel supports the specified DSTE Class Type. The circuitry can be further configured to, responsive to a failure of the LSP tunnel, select the Facility Bypass tunnel for the LSP tunnel such that the Facility Bypass tunnel supports the specified DSTE Class Type.