What Is Network Latency?
The latency of a network is the time it takes for a data packet to be transferred from its source to the destination. Also known as lag, network latency is generally measured in milliseconds. Network latency tools measure the amount of time a data packet takes as it’s transmitted and processed through various network devices until it finally reaches its destination and gets decoded by the receiving machine.
An acceptable latency range will depend on the network and the applications using the bandwidth on the network. The bandwidth required by different applications on a network can vary significantly. Applications like video or VoIP calls, require more bandwidth and lower latency range to function efficiently. Whereas, other applications (e.g., email) may allow higher latency range. Network administrators need to take such factors into account to allocate adequate resources and bandwidth and ensure mission-critical operations of the company run smoothly.
The problem of high latency is becoming more common as networks are growing bigger day by day. As the number of nodes or resources in a network increase, networks get overburdened over a period. Moreover, resolving network issues gets complicated as most businesses today have remote offices, multiple applications, and cloud and virtualized resources.
It may be noted that an application may experience issues even when a network is working perfectly fine. It’s not always easy to detect whether it’s a network latency or application bug leading to application performance degradation. Modern network latency tools can help IT teams deal with such issues with higher efficiency.
Possible Causes of Network Latency
DNS Server Errors
A faulty DNS server can be a cause of the poor performance of an application. Errors like 404’s and incorrect pathways can prevent potential visitors to reach your website.
Poorly Optimized Backend Database
Over-utilized databases can slow down your website severely. Also, higher table joins, complicated calculations, presence of large tables with long fields, and improper use of indexes are some of the common reasons for slow databases.
Low Memory Space
Low disk space is another reason system performance can decrease. In case of low disk space, the operating system will struggle and try to maintain RAM requirements being used by programs.
Selection of Transmission Mediums
Companies must carefully select the transmission media as it directly affects the speed of a signal. In a fiber-optic network, when an optical signal travels in a fiber link, latency occurs at every stage. Latency keeps increasing during every conversion, right from the time when the signal converts from electrical to optical domain, when it goes through the fiber, and finally when it converts from optical to electrical domain.
Multiple Routers
Routers take time to process the information in the header of a packet. When a packet transfers from router to router, the latency time gets increased.
How to Measure Latency?
Round Trip Time (RTT)
RTT is a common metric for latency measurement. It’s the total time taken by a data packet as it travels from its source to the destination and back. This time is also known as “round-trip time” (or RTT). This method of evaluation has a few disadvantages as it might not present a clear picture in cases when the return path is different.
Time to First Byte (TTFB)
Another metric for latency calculations is known as “time to first byte” (or TTFB). TTFB records the difference in time from the moment a data packet leaves a point on the network to the time it takes to reach the destination.
Ping
Ping is another commonly used latency testing method for the Internet Control Message Protocol (ICMP). The Ping command is used by network admins to measure the time it takes for 32 bytes of data to reach its destination plus the time it takes to receive a response in return. This command works on all operating systems with networking capabilities.
Ping is good for quick investigations. However, it doesn’t allow you to fix latency problems. It doesn’t give adequate information if you’re trying to check multiple paths from the same console. You’ll need additional network testing tools to get a clear view of your network flow and bottlenecks.
How to Resolve Latency Issues?
As every network is designed for particular workloads, network administrators have to keep track of any deviations or spikes in their bandwidth consumption. Firewalls provide options to define user groups and enforce bandwidth and QoS limits for different users in an organization. QoS (Quality of Service) allows you to prioritize time-sensitive application traffic over all other traffic. The method allows applications requiring time-sensitive data such as audio/video playback or VoIP calls to get prioritized bandwidth over other applications. Another solution is to implement sophisticated traffic shaping methods like queuing algorithms to optimize network traffic flow.
However, in complex networks, it isn’t easy to detect the root cause of network latency related issues. Organizations employ a range of network analysis and latency testing tools to reduce latency and manage bandwidth in their networks. These tools offer packet sniffing, NetFlow analysis, SNMP (Simple Network Management Protocol) monitoring, CBQoS (Class Based Quality of Service) monitoring and other proprietary network analysis features to help you keep track of network and resolve latency issues proactively.
Best Latency Testing Tool
There’s a wide variety of latency testing tools available in the market to help you measure the latency and pinpoint issues in the network. Tools like Paessler PRTG Network Monitor, ManageEngine NetFlow Analyzer, and Ping Plotter may suit your organization’s network testing requirements. However, based on user reviews, ease of usage, performance, and a wide coverage of features for network monitoring and analysis, we find SolarWinds® Network Performance Monitor is the best solution in the market.
SolarWinds Network Performance Monitor (NPM)
SolarWinds Network Performance Monitor helps you monitor all your network devices, physical and virtual servers, and applications using a single interface. SolarWinds proprietary NetPath feature enables visual analysis of a network with intelligent network maps. With these maps, you can track the flow of traffic between different nodes in your network. It also offers deep packet inspection. The feature helps you monitor response times and latency in a network over a Quality of Experience (QoS) dashboard. You can also use the network packet analyzer, which supports 1000-plus applications. This feature helps you to differentiate between network latency and application issues to identify what’s impacting application performance and user experience. Intelligent alerts and notifications along with a user-friendly dashboard, are some other major highlights of Network Performance Monitor. You can learn more about the product or sign up for a free trial for 30 days here.