Estimating Throughput

This page contains information regarding the data shown in the Throughput and Quality Analysis graph for circuit bandwidth utilization. This user interface graph is described on Review the Throughput by Circuit and Recommendations: Throughput and Quality Analysis Timeline.

Throughput data is only available for cEdge routers. See Enabling WAN Insights for more information on supported SD-WAN software versions.

To calculate bandwidth utilization, WAN Insights analyzes deep packet inspection (DPI) telemetry data coming from cEdge routers. This data can be collected in a few different ways.

  • One way is by using a tool called cFlowd, which can sample IPv4, IPv6, and (sometimes) MPLS and Ethernet traffic data flows. cFlowd is an optional SD-WAN feature and is not enabled by default. WAN Insights doesn't rely on cFlow data. However, if you enable cFlowd for an external collector export and use the cFlowd sampling option, then that sampling will also impact the DPI telemetry that WAN Insights relies on. This DPI telemetry is pulled from vManage.

  • You can configure cFlowd on top of DPI. cFlowd exports the flows to an external Netflow collector. On cEdge, IPv4/IPv6 are the only supported protocols for this purpose. MPLS and Ethernet are not supported.

The following conditions may have an impact on bandwidth utilization as shown in WAN Insights:

  • DPI telemetry data includes only traffic flowing from or to the service VPN. Control traffic in the transport VPN (VPN 0) is not reported in DPI. Thus, reported bandwidth is slightly lower than actual. However, control traffic is less than 1% of total traffic.

  • cFlowd includes a user-defined sampling interval that can impact DPI telemetry. When cFlowd is configured with a sampling interval value that is greater than 1, the reported DPI telemetry is also sampled. The reported values in WAN Insights will be smaller. For example, if the cFlowd sampling interval is set to 10, the reported bandwidth will be 1/10th the actual usage.

  • Any ThousandEyes monitoring tests that you may be running are included in the bandwidth calculation.

For more information:

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