SLA-Based Next-Hop Selection via Path Communities
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Solution Overview
Problem
Existing computer networks face challenges in maintaining Quality of Experience (QoE) by selecting paths that satisfy service level agreements (SLAs) due to link state violations, leading to suboptimal performance in parameters like latency, delay, jitter, and packet loss.
Innovation Solution
Implementing a controller that continuously monitors link state measurements and dynamically switches paths by instructing a virtual route reflector to add path communities to route advertisements, ensuring that traffic is forwarded over links that meet the defined SLAs, thereby improving QoE.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the network uses traditional routing protocols to forward traffic, then routing simplicity is maintained, but Quality of Experience (QoE) parameters such as latency, delay, jitter, and packet loss cannot be guaranteed to meet service level agreements
Solution Approach 1:
The patent introduces a Virtual Route Reflector (VRR) as an intermediary component that mediates between traditional routing protocols and SLA requirements. The VRR receives route advertisements, adds path community tags indicating SLA compliance, and reflects these enhanced routes to appropriate routers. This intermediary mechanism enables QoE guarantees without requiring fundamental changes to existing routing infrastructure, thus resolving the contradiction between reliability improvement and complexity increase.
Solution Approach 2:
The patent segments the routing information by introducing path communities that categorize routes according to their SLA compliance characteristics. Instead of treating all routes uniformly, the system divides routes into segments with different QoE properties (e.g., low-latency paths, high-bandwidth paths). This segmentation allows routers to select appropriate path segments based on service requirements while maintaining overall routing simplicity through standardized BGP extensions.
2Reliability
If the network dynamically switches paths based on link state measurements, then QoE is improved, but the complexity of path selection and monitoring increases
Solution Approach 1:
The patent implements self-service mechanisms where network elements autonomously monitor their own link state measurements and make path selection decisions based on pre-configured SLA policies. Routers continuously measure link performance metrics and automatically adjust path selection without requiring centralized control or complex coordination protocols. This self-service approach improves QoE while limiting complexity increase to local device operations rather than system-wide complexity.
Solution Approach 2:
The patent utilizes parameter changes in link state measurements (latency, bandwidth, packet loss) to dynamically adjust path selection. When measured parameters indicate SLA violations, the system automatically transitions to alternative paths with different parameter characteristics. This parameter-driven approach enables adaptive QoE management through standardized monitoring and adjustment mechanisms, avoiding the need for complex decision-making algorithms.
3Measurement precision
If path communities are added to route advertisements to indicate SLA compliance, then next-hop selection accuracy is improved, but processing overhead in route advertisements increases
Solution Approach 1:
The patent employs path communities as a universal mechanism that serves multiple functions simultaneously: they encode SLA compliance information, enable next-hop selection accuracy, and maintain compatibility with existing BGP infrastructure. The same path community tags used for SLA indication can also serve as standard BGP route attributes for general routing purposes. This multi-functionality improves next-hop selection precision without proportionally increasing processing overhead, as the same data structure serves multiple purposes.
Data Source
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AI summary
Techniques are described for selecting paths in accordance with service level agreements. For example, spoke and hub routers may advertise routes associated with virtual routing and forwarding (VRF) instances mapped to service level agreements (SLAs). A virtual route reflector of an intermediate router may receive route advertisements and may add respective path communities associated with particular links selected based on link state measurements in accordance with the SLAs. The hub or spoke routers may receive the route advertisements including a respective path community and install the selected path as a next-hop for a given SLA. In this way, spoke and hub routers may forward traffic on links that satisfy particular SLAs such that Quality of Experience (QoE) for an application may be restored or improved.