On-Demand Direct Tunnel Establishment in SD-WAN
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Solution Overview
Problem
In SD-WAN networks, full-mesh and hub-and-spoke deployments face challenges with tunnel scalability due to low-end edge routers and latency issues, making it difficult to sustain connections and maintain application performance, especially for latency and bandwidth-heavy applications.
Innovation Solution
Implementing a hub-and-spoke deployment with on-demand direct site-to-site tunnel establishment, allowing sites to selectively switch to direct forwarding based on configured triggers, such as packet, application, or flow duration triggers, and tearing down tunnels when not needed, thereby avoiding the requirement for a full mesh of tunnels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a full-mesh topology is implemented in SD-WAN, then direct connectivity between all sites is achieved, but device complexity and memory requirements increase significantly for low-end edge routers
Solution Approach 1:
The patent segments the full-mesh topology into hierarchical levels: core sites maintain full-mesh connectivity while remote sites connect only to their nearest core site. This segmentation reduces the number of tunnels each router must maintain, lowering device complexity while preserving direct connectivity where most needed.
Solution Approach 2:
The patent introduces a spatial dimension to tunnel provisioning by geolocating sites and determining nearest core sites based on physical distance. This transforms the flat full-mesh approach into a geographically-aware hierarchical structure, reducing complexity while maintaining direct connectivity for remote sites to their nearest core site.
2Ease of manufacture
If low-end edge routers with reduced memory and processing capabilities are used, then deployment cost is reduced, but ability to sustain connections with every other remote site deteriorates
Solution Approach 1:
The patent segments the network into core sites (with high-capacity routers) and remote sites (with low-end routers). Remote sites only maintain connections to their nearest core site rather than all other sites, enabling low-end routers to sustain connections reliably within their reduced capacity constraints while maintaining overall network reliability.
Solution Approach 2:
Core sites act as intermediaries between remote sites. Remote sites with limited capabilities connect to their nearest core site, which then provides connectivity to other parts of the network. This intermediary approach allows low-end routers to participate in the network without needing to sustain direct connections to all other sites.
3Productivity
If direct tunnels are established between all sites, then application performance is improved, but bandwidth requirements and network resource consumption increase
Solution Approach 1:
The patent applies local quality by establishing direct tunnels only where they provide the most benefit: between remote sites and their nearest core sites based on geolocation. This selective approach improves application performance for latency-sensitive traffic while avoiding the excessive bandwidth consumption of full-mesh tunnels between all site pairs.
Solution Approach 2:
The patent implements partial direct tunneling rather than complete full-mesh tunneling. Direct tunnels are established partially - only for remote sites to their nearest core sites - which is sufficient to improve application performance for most traffic while significantly reducing bandwidth requirements compared to establishing excessive tunnels for all possible site pairs.
Data Source
AI summary
The present disclosure is directed to a mechanism for optimized application performance in SD-WAN, and includes the steps of receiving initial traffic packets at a first site for transmission to a second site; determining whether a direct tunnel is established between the first site and the second site based on a state of the second site, the state comprising an active state indicating that a direct tunnel is established between the first and second sites or an inactive state indicating that the direct tunnel is not established between the first and second sites; and in response to determining that the direct tunnel is not established, determining that the initial packets satisfy a configured trigger; forwarding the initial packets to the second site via a backup path; establishing the direct tunnel between the first and second sites; and forwarding subsequent traffic packets to the second site via the established direct tunnel.