--- title: "SD-WAN Monitoring" slug: "sd-wan-monitoring-1-1" updated: 2026-01-13T03:10:04Z published: 2026-01-13T03:10:04Z canonical: "docs.catchpoint.com/sd-wan-monitoring-1-1" --- > ## Documentation Index > Fetch the complete documentation index at: https://docs.catchpoint.com/llms.txt > Use this file to discover all available pages before exploring further. # SD-WAN Monitoring ## Overview SD-WAN (Software-Defined Wide Area Network) is an intelligent, software-controlled approach to managing enterprise WAN connectivity. It uses multiple transport links such as MPLS, broadband, and LTE and automatically selects the best path for each application based on real-time conditions like latency, loss, and jitter. While SD-WAN optimizes network routing, it often hides where performance issues originate. The SD-WAN controller may report that all tunnels are healthy, yet users experience latency or application slowness. Monitoring SD-WAN provides the visibility needed to identify whether an issue lies in the overlay, underlay, or application layer. ## Key Concepts - **Underlay** The *underlay* refers to the physical transport layer MPLS, broadband, or LTE that carries traffic between sites. It provides basic connectivity but does not inherently manage or optimize traffic routing. - **Overlay** The overlay is a virtual layer built over the underlay using encrypted tunnels (typically IPsec). It intelligently routes traffic, applying SD-WAN policies and prioritization to ensure optimal performance and reliability. ## Why Monitoring SD-WAN is Important SD-WAN abstracts physical networks and dynamically reroutes traffic. However, this abstraction can mask performance issues such as: • Unstable ISP (underlay) connections • Misrouted SD-WAN tunnels (overlay) • SaaS, CDN, or DNS degradation Monitoring both overlay and underlay ensures that IT teams can quickly determine whether performance problems originate in the network, SD-WAN policy, or the application itself. ## Catchpoint SD-WAN Monitoring Approach Catchpoint provides **end-to-end visibility** across SD-WAN environments using **synthetic testing**. ![Image](https://cdn.document360.io/cb4af8f9-6751-4fd2-b39c-07aae832badb/Images/Documentation/image(597).png) **How It Works** 1. Deploy two Enterprise Nodes: - One *inside* the SD-WAN. (behind the edge router) - One *outside* on a public link. 1. Run tests such as Ping, Traceroute, HTTP/Chrome, and Object. 2. Compare overlay and underlay results to isolate the true cause of degradation. **Metrics Tracked** 1. Latency 2. Packet Loss 3. Jitter 4. Connection Errors 5. Bandwidth/Throughput 6. Application Load Time **Benefits** • Pinpoint whether degradation occurs in the overlay, underlay, or application. • Validate SD-WAN path selection and routing decisions. • Ensure end-user experience aligns with network health. ## Use Cases **Overlay vs Underlay Visibility** ![Image](https://cdn.document360.io/cb4af8f9-6751-4fd2-b39c-07aae832badb/Images/Documentation/image(599).png) **Purpose**: Identify where performance issues originate. **Description**: Tests overlay and underlay paths simultaneously to reveal latency, loss, and routing differences. **Outcome**: Quickly isolate whether an issue is within the SD-WAN tunnel or the physical ISP network. ## Branch Link and ISP Path Comparison ![Image](https://cdn.document360.io/cb4af8f9-6751-4fd2-b39c-07aae832badb/Images/Documentation/image(600).png) **Purpose**: Compare routing efficiency across multiple ISPs. **Description**: Catchpoint visualizes route hops and latency differences in real time, highlighting longer or unstable paths. **Outcome**: Select the optimal ISP per site and validate SD-WAN routing policies. ## PoP Reachability and Underlay Health ![Image](https://cdn.document360.io/cb4af8f9-6751-4fd2-b39c-07aae832badb/Images/Documentation/image(601).png) **Purpose**: Ensure stable branch-to-PoP connectivity. **Description**: Continuous Ping and Traceroute tests monitor link health between branches and SD-WAN provider gateways. **Outcome**: Detect underlay issues before they impact SD-WAN tunnels. ## Application Experience over SD-WAN ![Image](https://cdn.document360.io/cb4af8f9-6751-4fd2-b39c-07aae832badb/Images/Documentation/image(602).png) **Purpose**: Measure true SaaS performance across SD-WAN links. **Description**: Synthetic browser and transaction tests simulate user journeys to SaaS apps like Microsoft 365, Salesforce, or Zoom. **Outcome**: Correlate application performance with SD-WAN path quality. ## Failover Validation ![Image](https://cdn.document360.io/cb4af8f9-6751-4fd2-b39c-07aae832badb/Images/Documentation/image(603).png) **Purpose**: Confirm uninterrupted service during link outages. **Description**: Continuous Ping and HTTP tests detect rerouting behaviour and measure failover duration. **Outcome**: Validate SD-WAN failover efficiency and maintain uptime during link loss. ## Bandwidth Verification (Throughput Testing) ![Image](https://cdn.document360.io/cb4af8f9-6751-4fd2-b39c-07aae832badb/Images/Documentation/image(604).png) **Purpose**: Measure delivered bandwidth across SD-WAN links. **Description**: Catchpoint runs iPerf/FTP throughput tests between Enterprise Nodes to verify capacity and detect degraded links. **Outcome**: Confirm link SLA compliance and detect performance bottlenecks early. ## User and Endpoint Experience Monitoring ![Image](https://cdn.document360.io/cb4af8f9-6751-4fd2-b39c-07aae832badb/Images/Documentation/image(605).png) **Purpose**: Correlate user device performance with network metrics. **Description**: Endpoint Agents collect Wi-Fi, DNS, and latency data from user machines and correlate with SD-WAN branch data. **Outcome**: Quickly isolate whether slowness is caused by local, branch, or network-wide factors.