Network Performance Metrics

Network performance metrics are a collection of metrics that measure how well or poorly a network performs. Network performance metrics can reveal when components of a network are behaving irregularly and need further investigation.

Network operations teams can select from hundreds of metrics to tailor their network health assessment to the most important metrics for the priorities of their network. Selecting the right combination of network performance metrics to give your NetOps teams the most meaningful metrics is a science that is unique to each organization’s specific needs. Some of the most common network performance metrics include:

Bandwidth Utilization

Bandwidth utilization refers to the amount of bandwidth consumed on a network or on a specific network segment and the breakdown of its composite traffic. Understanding how bandwidth is utilized in a network is of critical importance to a network manager who is chiefly responsible for ensuring peak network performance. Modern network monitoring software can track traffic throughout large and complex networks and determine how bandwidth is being utilized. For example, software solutions can monitor bandwidth utilization by port and even by direction to pinpoint problems or justify additional bandwidth.

Network Latency

Network Latency is the amount of time it takes a packet to go from its host to its destination, also characterized as travel delay.

Jitter

This is the change in latency between packet delivery. Low jitter is described as a consistent frequency in packet arrival. When the output signals begin to vary, but the changes are slow, this is called wander. Wander is the precursor behavior to jitter. Rapid variations and delays between packet arrivals are called high jitter. Jitter can be caused by routing changes, network congestion, inadequate resource allocation, distance, and changes in the weather.

Packet Loss

Packet loss happens when one or more packets fail to reach their destination. It can be caused by hardware failure, saturated network nodes, environmental or man-made interference, buggy software, or a cybersecurity attack.

Throughput

Throughput measures how much data can successfully be processed from a source to a destination over a given period of time. The formula used for the rate of throughput is bits per second (bps), bytes per second (Bps), or data packets per second (pps).

Error Rate

The error rate is the ratio of incorrectly transferred bits to the total number of bits received in the transfer, expressed in a percentage. This can also be measured at a packet level instead of by bits, called the Packet Error Rate. Errors can be caused by interference, noise, faulty devices, and congestion. A high error rate indicates an unreliable connection.

Round Trip Time (RTT)

RTT is a measurement in milliseconds of how long it takes a network request to go from its starting point to its destination and back to the starting point, or round trip. For example, RTT can measure how long it takes between when a browser sends a request to when it receives a response from a server. This metric helps network administrators understand the speed of page load time and the health of specific connections. A reduced RTT also means a reduction in network latency.

Retransmission Rate

Retransmission rate, also known as TCP retransmission, is what happens when packets that are dropped, damaged or held back due to buffering get resubmitted. Each TCP segment has a sequence number, if there is a gap in the numbers received, retransmission will occur. A retransmission rate above 2% impacts the user experience. Excessive retransmission can indicate packet loss or slow application performance that runs out the TCP timer.

Time to First Byte (TTFB)

TTFB measures how long it takes the first byte of an HTTP request to be received by the client’s browser. This measurement can tell network admins how responsive a webserver is to a site visitor’s browser request. TTFB should be 200 milliseconds or less. Slower TTFB can be caused by high traffic, network issues, server misconfiguration, or an overkill of dynamic content on a website that slows load time.

Benefits of Using Network Performance Metrics

Advanced Network Visibility

Network performance metrics give your team insights into failing devices and saturated links and provide notice when you might be outgrowing existing resource allocation for different sites or applications. Without network performance metrics it would be impossible to measure network health and performance over time.

Improved Network Troubleshooting

Network performance metrics can indicate potential trouble and move network troubleshooting into a more proactive than reactive activity for NetOps teams. Metrics like packet loss and round trip time (RTT) are critical to understanding where bottlenecks are happening in a network so they can be effectively addressed.

Access to Network Trends Analysis

Network performance metrics gathered over time can reveal important network trends like peak traffic hours or can help teams reevaluate QoS policies for more efficient routing.

Benefits of Using Network Performance Metrics

Advanced Network Visibility

Network performance metrics give your team insights into failing devices and saturated links and provide notice when you might be outgrowing existing resource allocation for different sites or applications. Without network performance metrics it would be impossible to measure network health and performance over time.

Improved Network Troubleshooting

Network performance metrics can indicate potential trouble and move network troubleshooting into a more proactive than reactive activity for NetOps teams. Metrics like packet loss and round trip time (RTT) are critical to understanding where bottlenecks are happening in a network so they can be effectively addressed.

Access to Network Trends Analysis

Network performance metrics gathered over time can reveal important network trends like peak traffic hours or can help teams reevaluate QoS policies for more efficient routing