Where Can I Use This?	What Do I Need?
Prisma SD-WAN	Active Prisma SD-WAN license

Prisma SD-WAN allows network administrators to meet their application Service Level Agreements (SLAs) with its Path, QoS, and Security policies. Through the Prisma SD-WAN path policy, you can define rules to express business intent for which paths are allowed per application. The ION devices evaluate each application session against the defined path policy and select the WAN path that meets the application-specific SLA. One of the many mechanisms used to determine if a path will meet an application’s SLA is monitoring the Link Quality.

The Dashboard > Overall Link Quality on the Prisma SD-WAN web interface provides the aggregate link quality metrics of all branch and data center sites at a glance. It includes information on the MOS, packet loss, jitter, and latency of the links. View data in the last available 5 minutes' time frames and the last available 1 hour of any metric.

Prisma SD-WAN determines link quality by actively probing the Secure Fabric VPN paths over public and private transports and the private WAN underlay paths. The probes provide a constant measurement of network performance metrics, such as jitter, latency, and packet loss. These metrics, along with application-specific performance metrics and Layer 1 – Layer 7 reachability inform traffic forwarding decisions for new and existing application flows.

By default, Link Quality metrics influence path selection for all real-time voice and video applications. If a link is considered acceptable, the real-time application will stay on the initially selected path. Still, when the link is degraded or considered inadequate, the ION device will seamlessly move all existing and subsequent real-time application flows to a suitable alternate path as allowed by policy, if available.

Based on the link quality metrics chosen, you can filter the information based on Interval, Start Time, and Direction. Using the interactive dashboard, you can change the metric to any other link quality metrics to view the corresponding graphs. The last distribution range of the bar graph up to the 90th percentile of the available data.

The Link Quality Metrics provides a snapshot of the current state of the links you are monitoring. You gain insight into the dashboard's Link Performance, Link Packet Loss, Link Jitter, and Link Latency. Links are displayed by default for all your sites and for the most recent time period (last available 5 minutes or last available hour). The interactive dashboard provides filters to change the scope of information displayed; it allows you to analyze information you want to view in greater detail in the Link Quality Details tab.

Click View Details to see the detailed view of the links table. The table enables you to view all secure fabric links between two sites along with Circuit and WAN information. You can also view the link quality metrics and link type for each link. You can sort the table information based on a particular link quality metric displaying the corresponding worst value on top. Expand the site detail to view the link quality metrics for ingress and egress flows. It enables you to view the link quality chart per site and path. The chosen site and active path are the pre-selected filter criteria for the Activity chart that displays the corresponding information.