Network Metrics

    What you are going to learn:

  • What are the network metrics measures by the network performance monitoring features.

Once a Network Monitoring Session is established between two Monitoring Agents, the session will start collecting network metrics. This article will describe the network metrics that are measured for each and every session.

Basic Network Metrics
Basic Network Metrics

While sending the network performance measurement packets, the client and server agents add timing and sequence information that are analyzed by the client agent to measure the following network metrics:

  • Latency refers to the measure of time it takes for data to reach its destination across a network. It is usually measured as a round trip delay, in milliseconds (ms), taking into account the time it takes for the data to get to its destination and then back again to its source.

  • Jitter refers to the variation of the latency. To calculate the jitter, the current latency for a session is compared to the previous latency value. For example, if the latencies are 5ms 10ms 5ms 10ms 50ms, the jitter values will be 5ms 5ms 5ms 40ms.

  • Packet Loss refers to the percentage of data packets that were sent by the client agent, and which received no response from the server. Over a period of 1 minute, 120 measurement packets are sent. If 5 packets are dropped by the network, the packet loss rate will be 4.2%.

In the Network Monitoring Session Graphs, the multiple percentiles of the latency and jitter are shown.

Quality of Experience Metric
Quality of Experience Metric

Based on the basic network metrics introduced in the previous section, the Quality of Experience (QoE) metric is calculated to figure out how good or bad the user's experience was with a VoIP call during a period of time. Learn more on the VoIP Quality experience metric.

Advanced Network Metrics
Advanced Network Metrics

In addition to the basic network metrics, the network performance measurement packets also offer some advanced metrics such as Packet Reordering, Packet Duplication and QoS DSCP Mismatch.

Blog Post
Blog Post

A more detailed article about network metrics is available in our Blog: How to Measure Network Performance: 5 Network Metrics.