Businesses today rely heavily on SD-WAN to deliver optimal Internet, cloud, and voice performance. While SD-WAN offers many advantages, network problems, if not adequately understood and mitigated, potentially still impact performance. The most common issues, such as network bandwidth congestion or high resource utilization, often occur on the last mile or customer premise equipment (CPE), which are highly prone to congestion and related symptoms. Understanding where these problems occur and how to address them effectively can optimize the deployment of SD-WAN solutions and network performance overall.

The Role of Underlay & Overlay Networks in Problem Resolution

• The Underlay Network: The underlay refers to the physical or virtual network infrastructure supporting the SD-WAN deployment. Problems such as network congestion, link failures, or inadequate bandwidth in the underlay network can severely impact SD-WAN performance. SD-WAN solutions that cannot adequately address underlay issues will experience poor performance, regardless of how advanced the overlay is.

• The Overlay Network: The overlay is created by the SD-WAN solution and operates on top of the underlay network. Overlay problems can include misconfigurations, policy conflicts, or suboptimal routing decisions, all of which can impact the overall performance and reliability of the SD-WAN solution. Proper monitoring and configuration of the overlay can help mitigate these issues. One of the primary problems around the overlay is a poor choice of architecture.

The Common Problem Areas in Networking

1. Last Mile Connectivity: The last mile is the weakest link in most network infrastructures and represents the final segment that connects businesses to the broader network. SD-WAN’s effectiveness hinges on this link, but up to 75% of network problems stem from last-mile issues. Problems here include single points of failure, limited route diversity, and slower speeds, all of which hinder the SD-WAN’s ability to deliver optimal performance.

   Many SD-WAN deployments use link diversity to mitigate the risks of last-mile problems, relying on multiple transport links like leased lines, broadband, or 4G/LTE. The idea is that a failure in one link won't affect the others, allowing traffic to be dynamically routed over the best available link. However, while link diversity reduces risks, it doesn’t always eliminate them, especially if other aspects of the SD-WAN solution are lacking.

2. ISP Backbone Congestion: Even though ISP backbones are more robust and reliable than other parts of the network, congestion and performance degradation on their peering and transit paths can still cause problems. This problem can even stretch to the IP Transit being used by the ISP. The interaction between your SD-WAN solution and the ISP's backbone can sometimes be impacted by congestion points, which can lead to performance hiccups.

3. Network Congestion & Bandwidth Limitations: The majority of network problems businesses experience, including those on SD-WAN networks, are attributed to bandwidth congestion or bottlenecks. These bottlenecks typically occur on the last mile, where the connection between the business's premises and the ISP can easily get congested. Additionally, network bottlenecks can arise from high resource utilization on customer premise devices, like routers and firewalls, especially if these devices are overloaded with tasks such as packet inspection and encryption.

4. Packet loss: Packet loss is potential triggered by a number of underlying causes. A packet loss of 1% can result in a minimum of 16% degradation on performance.

Identifying & Addressing Common Problems

1. Transport Link Issues: SD-WAN leverages different transport methods, such as leased lines, broadband, or 4G/LTE, for connectivity between locations. If these links are unstable, congested, or underperforming, businesses may experience latency, packet loss, or unreliable connectivity. Without the use of WAN optimization, which many firewall-based SD-WAN solutions lack, these problems can worsen, resulting in degraded performance.

2. Dynamic Routing & Application Prioritization Problems: SD-WAN dynamically routes traffic based on policies, prioritizing applications for optimal performance. If traffic isn’t accurately identified or prioritized, it may lead to suboptimal routing or performance degradation. This problem is often seen with solutions that lack robust application identification features or are complex to configure. Solutions like Fusion's SD-WAN, which comes with battle-hardened templates out of the box, are designed to avoid such misconfigurations.

3. Controller Overload: SD-WAN solutions have centralized controllers that manages network policies and orchestrates routing. When a controller is overloaded or misconfigured, it can disrupt the entire SD-WAN deployment. Scalable controllers, like those in Fusion's SD-WAN, can adjust to increasing loads, ensuring that performance remains unaffected.

4. Application-Specific Issues: SD-WAN aims to optimize application performance by routing traffic dynamically. Problems can occur if critical applications aren't properly identified, leading to degraded performance. Packet-based solutions, such as Fusion’s, help eliminate these problems by improving traffic flow and ensuring critical applications get the necessary resources.

5. Edge Device Failures: SD-WAN deployments typically involve edge devices at remote sites. Hardware or software failures, misconfigurations, or compatibility issues with other network components can degrade the network. Ensuring that these devices are properly configured and monitored is essential, as a single failure can lead to site-wide network problems. Fusion’s SDWAN uses premium grade Intel appliances and not plastic dinky toys.

Security, Compatibility, & Management Challenges

1. Complexity in Deployment & Management: Some SD-WAN solutions, particularly those from Silicon Valley "gorillas," are complex and difficult to deploy, manage, and troubleshoot. By contrast, solutions like Fusion’s SD-WAN offer more user-friendly and cookie-cutter implementations, reducing complexity and streamlining the deployment process.

2. Security Vulnerabilities: While SD-WAN enhances security through features like encryption and segmentation, misconfigurations can introduce vulnerabilities, making the network susceptible to breaches or data leakage. Firewall-based SD-WAN solutions, in particular, have been known to have vulnerabilities. This can easily be observed via viewing the CISA Known Exploited Vulnerabilities Catalog. Ensuring robust security measures are in place and configuring the solution properly is crucial.

3. Network Compatibility: SD-WAN often integrates with existing network infrastructure like firewalls, routers, and switches. Compatibility problems between different vendors can lead to limited functionality and configuration difficulties. Businesses should ensure their SD-WAN solution is agnostic and can seamlessly integrate with various components of the network.

Visibility & Troubleshooting | Key to Proactive Management

Visibility is crucial for identifying and troubleshooting SD-WAN issues. Businesses need end-to-end visibility into their SD-WAN deployment to monitor resource usage, bandwidth consumption, and packet loss effectively. High resource usage on SD-WAN devices can severely impact performance, leading to delays and packet loss that affect network sessions.

With advanced traffic analytics solutions, like Fusion’s Illuminate, businesses can gain full visibility into their network, enabling proactive management and troubleshooting of performance issues.

Wrap | Optimizing SD-WAN for Your Business

By understanding the most common SD-WAN problems and implementing proactive measures, businesses can mitigate performance issues and ensure optimal operation. Identifying bottlenecks in the last mile, addressing controller scaling, and ensuring proper configurations are all key to avoiding potential pitfalls.

Whether you're using SD-WAN for cloud applications, VoIP, or business-critical data, adopting a battle-tested solution like Fusion’s SD-WAN will help your business sidestep many of the common issues associated with complex, multi-vendor, or legacy-based deployments.

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Ronald Bartels ensures that Internet inhabiting things are connected reliably online at Fusion Broadband South Africa - the leading specialized SD-WAN provider in South Africa. Learn more about the best SD-WAN in the world: 👉Contact Fusion🚀

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