Packet loss is one of the most important network performance metrics, but what is packet loss, what causes it and how do you fix it?
What is packet loss?
Packet loss refers to any packets of data that are lost or dropped in transit during travel across a computer network.
Packet loss could be due to a failure or an inefficiency of a component that carries data across a network, such as a faulty router, a loose cable connection or a bad wifi signal.
Lost packets can also be intentional, for instance when it is used to restrict throughput during VoIP calls or video streams so as to avoid time lags, particularly during times of high network congestion. This results in lower quality streams and calls which negatively affect user experience. To fix packet loss and keep high latency, you need to determine which parts of your network are contributing to the problem.
- 1 What is packet loss?
- 2 How to fix packet loss
- 3 Network monitoring tools to stop packet loss
- 4 Determining the likelihood of packet loss
- 5 Packet loss considerations
- 6 Tools to detect and troubleshoot packet loss
- 7 Packet Loss FAQ
- 8 What causes packet loss on a network?
- 9 How do you calculate packet loss?
- 10 Why do I have packet loss with Ethernet?
- 11 Conclusion
How to fix packet loss
- Check physical network connections – Check to make sure that all cables and ports are properly connected and installed.
- Restart your hardware – Restarting routers and hardware throughout your network can help to stop many technical faults or bugs.
- Use cable connections – Using cable connections rather than wireless connections can improve connection quality.
- Remove sources of interference – Remove anything that could be causing interference. Power lines, cameras, wireless speakers and wireless phones all cause interference in networks.
- If your running WIFI – Try switching to a wired connection to help reduce packet loss on your network.
- Update device software – Keeping your devices updated will help to ensure that there are no bugs in the OS causing packet loss.
- Replace outdated or deficient hardware – Upgrading your network infrastructure allows you to get rid of deficient hardware altogether.
- Use QoS settings – Prioritize your network traffic based on the applications that are most important. For example, prioritize voice or video traffic.
Network monitoring tools to stop packet loss
The more tightly knit a network, with better routers and connections in place, the less likely it is to face packet loss. But invariably many communications happen using the Internet Protocol, and not all hops are known along the way. The endpoints are in the best position to work out if retransmission of dropped packets should take place. This means that we should always anticipate some level of packet loss and therefore packet recovery in data communications. Fortunately, some very effective network monitoring systems are available today.
We cover each of the tools that made this list in much more detail below, but if you only have time for a summary, here is our list of the 5 best network monitoring systems:
- SolarWinds Network Performance Monitor EDITOR’S CHOICE Comprehensive network device health checker, running on Windows Server, that employs SNMP for live monitoring.
- Paessler Packet Loss Monitoring with PRTG (FREE TRIAL) A network, server, and application monitoring tool that includes a Ping sensor, a Quality of Service sensor, and a Cisco IP SLA sensor.
- ManageEngine OpManager Network management system for Windows and Linux that uses SNMP to check on device statuses.
- Nagios XI Free network management suite that runs on Linux.
- Progress WhatsUp Gold Windows-based network management tool that uses SNMP procedures to communicate with network devices.
Determining the likelihood of packet loss
Packet loss is less likely on private, wired networks, but highly probable on long-distance internet connections. The IP philosophy of passing data packets across networks gives each router the decision on where a packet should be passed to next. The sending computer has no control over the transfer speed or the route that the packet will take.
The reliance on individual routers to make routing decisions means each access point on the route must maintain a database of preferable directions for each ultimate destination. This disconnected strategy works most of the time. However, one router cannot know instantly if another router further down the line is overloaded or defective.
All routers periodically inform their neighboring devices of status conditions. A problem at one point ripples through to recalculations performed in neighboring routers. A traffic block in one router gets notified to all of the routers on the internet, causing all routers to recalibrate paths that would otherwise have passed through the troubled router. The chain of information takes time to propagate.
Sometimes a router will calculate the best path and send a packet down a blocked route. By the time the packet approaches that block, the routers closer to the problem will already know about it and reroute the packet around the defective neighbor. That rerouting can overload alternative routers. If the defect on a router prevents status notifications from being sent out, then the packet will be sent to that router regardless.
In short, the further a packet has to travel, the more routers it will pass through. More routers mean more potential points of failure and a higher likelihood that dropped packets will occur.
Packet loss considerations
You will never reach a point where your company’s network infrastructure achieves zero packet loss. You should expect this performance drag when making connections over the internet, in particular.
Once you understand the reasons for packet loss, keeping the network healthy, packet recovery becomes an easier task. Install a network monitor to prevent equipment failure, security risks, and system overloading that escalates packet loss to critical conditions.
Packet loss costs your business money because it causes extra traffic. If you don’t deal with packet loss, you’ll have to compensate by purchasing extra infrastructure and higher levels of internet bandwidth usage than you would need with a well-tuned system.
Tools to detect and troubleshoot packet loss
These tools both help you identify the equipment causing packet loss and provide continuous device monitoring to prevent packet loss whenever possible.
The SolarWinds Network Performance Monitor includes an autodiscovery function that maps your entire network. This discovery feature sets up automatically and then recurs permanently, so any changes in your network will be reflected in the tool. The autodiscovery populates a list of network devices and generates a network map.
The monitor tracks the performance of wireless devices and VM systems.
The tool picks up SNMP messages that report on warning conditions in all network devices. You can set capacity warning levels when monitoring router traffic to spot routers and switches nearing capacity. Taking action in these situations helps you head off overcapacity which results in packet loss.
The management console includes a utility called NetPath that shows the links crossed by paths in your network. The data used to create the graphic is continually updated and shows troubled links in red so that you can identify problems immediately. Each router and switch in the route is displayed as a node in the path. When you hover the cursor over a node, it shows the latency and packet loss statistics for that node.
Network Performance Monitor extends its metrics out to nodes on the internet. It can even see inside the networks of service providers, such as Microsoft or Amazon, and report on the nodes within those systems.
NetPath gives great visibility to packet loss problems and lets you immediately identify the root cause of the problem. The SNMP controller module lets you adjust the settings on each device remotely, so you can quickly resolve packet loss problems on your network.
If you run your voice system over a data network, you should consider the SolarWinds VoIP and Network Quality Manager. This tool particularly focuses on network conditions important to successful VoIP delivery. As packet loss is a major problem with VoIP, this module hones in on that metric. The system includes a visualization module that shows the paths followed by VoIP, along with the health of each node in color-coded statuses. This tool extends VoIP quality monitoring across sites to cover your entire WAN.
Both of these SolarWinds products run on a common platform and can be integrated together. All SolarWinds infrastructure monitoring systems run on Windows Server. You can get a 30-day free trial for both of these tools.
SolarWinds Network Performance Monitor: Map your entire network to get visibility on packet loss and identify the root cause of the problem. Overall, a vital tool that is great for reducing packet loss to 0% or as close as possible
Get 30 Day Free Trial: solarwinds.com/network-performance-monitor/
OS: Windows Server 2016 or later
Paessler is a significant player in the network monitoring software sector and it puts all of its expertise into one killer product: PRTG. The company prices its product by a count of sensors. A “sensor” is a network or device condition, or a hardware feature. You need to employ three sensors to prevent or resolve packet loss.
The Ping test sensor calculates packet loss rate and trip time at each device. The Quality of Service sensor checks on packet loss over each link in the network. The third is the Cisco IP SLA sensor that only collects data from Cisco network equipment.
The ongoing system monitoring routines of PRTG head off conditions that cause packet loss. First of all, you need to make sure that no software bugs or hardware failures will cripple the network. PRTG uses SNMP agents to constantly monitor for error conditions on each piece of hardware on the network. Set alert levels at the processing capacity of each network device and marry that to a live monitor of the network’s throughput rate per link. The build-up of traffic in one area of the network may cause overloading on the related switch or router and in turn cause it to drop data packets.
The PRTG system monitors application performance, too. You can prevent network overloads if you spot a sudden spike in the traffic generated by one application just by blocking it temporarily. You can also track the source of traffic back to a specific endpoint on the network and block that source to head off overloading.
The dashboard of PRTG includes some great visualizations, which include color-coded dials, charts, graphs, and histograms. The mapping features of PRTG are impressive and offer physical layout views both on the LAN and across a real-world map for WANs. A Map Editor lets you build your own network representations by selecting which layer to display and whether to include the identification of protocols, applications, and endpoints.
Paessler PRTG’s monitoring extends into the Cloud, will enable you to monitor remote sites, uncover network problems, while also covering wireless devices and virtual environments. You can install PRTG on the Windows operating system or opt to access the system over the internet as a Cloud-based service. Paessler offers a 30-day free trial of PRTG.
OpManager features a very sophisticated dashboard that manages to crowd in a lot of information without overwhelming the viewer. You can customize the dashboard and make different versions for different team members. The installation process ends with a network discovery phase, which populates the OpManager system database. The monitor builds a graphical representation of your network that can extend to WANs and wireless equipment. If you have virtual environments, OpManager maps both the virtual and physical elements of your system.
The network monitoring system uses SNMP to continue monitoring the health of all devices on the network. The SNMP system gives device agents the power to send out alert messages called “traps.” The controller displays these alerts on the dashboard immediately and can also be set to issue notifications by email or SMS. This monitoring system helps prevent any emergency performance issues that cause packet loss.
The alert logging system offers you the easiest way to detect and resolve issues that result in packet loss. One of the alert conditions is packet loss. That alert is tied to a specific network device. On clicking on the notification, the OpManager dashboard takes you to a page about that piece of equipment and shows performance metrics in visual formats. This gives you a quick way to check which condition caused the increased packet loss rate.
If no aspect of the router’s performance shows you problems, you can also click through to read the configuration changelog. If raised packet loss rate coordinates with a configuration change, you can roll back the settings of the device to its state before those changes to see whether that resolves the problem.
OpManager gives you all the information you need to prevent, resolve or reduce packet loss with just a few clicks. This system can be installed on Windows or Linux and is available for a 30-day free trial.
Nagios Core is a free and open-source program. The only problem is that no user interface is included. In order to get full GUI controls, you must pay for the Nagios XI system.
Like all of the other recommendations on this list, Nagios XI discovers all of the devices connected to your network and lists them on the dashboard. It will also generate a map of your network. Ongoing status check head off potential packet loss-provoking performance problems.
Statuses are checked by the proprietary Nagios Core 4 monitoring system rather than SNMP. However, Nagios can be extended by free plug-ins, and an SNMP-driven monitoring system is available in the plug-in library. Traffic throughput rates, CPU activity, and memory utilization appear as statuses on the dashboard include. By setting alert levels on these attributes, you can get sufficient warning to prevent overloading of each of your network devices.
A Configuration Management module checks the setup of each device on the network and logs it. The log records changes made to those configurations. If a new setting impacts performance, such as increased packet loss, you can use the Configuration Manager to instantly roll back settings on a device to an earlier configuration.
The dashboard of Nagios XI includes some very attractive visualizations with color-coded graphs, charts, and dials. You can customize the dashboard and create versions for different team members as well as non-technical managers who need to stay informed.
The Nagios XI package includes all the widgets needed to assemble a custom dashboard through a drag-and-drop interface that makes it easy to stop packet loss. The system comes with standard reports and you can even build your own custom output.
Nagios records and stores performance data, so you can operate the interface’s analysis tools to replay traffic events under different scenarios. The capacity planning features of this system will help spot potential overloading that would cause packet loss.
Nagios XI will cover virtual systems, cloud services, remote sites, and wireless systems as well as traditional wired LANs. You can only install this monitor on CentOS and RHEL Linux. If you don’t have those but do have VMware or Hyper-V machines, you can install it there. Nagios XI is available for a 60-day free trial.
The Progress (formerly Ipswitch) product WhatsUp Gold monitors network devices and warns of potential error conditions, including device memory and CPU exhaustion. These alerts are managed via SNMP and you can head off capacity and failure problems that cause packet loss.
This software includes a network discovery feature, that collects all of the data for the monitor. It continually updates the topology of the LAN, detecting inventory additions, relocations, and removals. The discovery process creates a device list and builds a network map. This map is compiled from data gathered at the Data Link and Network layers. The map displays troubled devices in red. The mapping of network links extends out to the Cloud and also includes virtual environments and wireless devices.
Performance metrics like packet loss are shown in the device list and on the network map.
The WhatsUp Gold dashboard provides access to both live and historical data. This performs analysis on traffic demand trends. Live alerts raised when certain conditions are met according to pre-set rules, and you can set your own custom alert conditions. The alerts can be sent out to team members as emails, SMS messages, or Slack notifications.
WhatsUp Gold installs on Windows Server and you can get a free trial.
Packet Loss FAQ
What causes packet loss on a network?
The most common cause of packet loss on a network is overloaded network devices. Switches and routers will drop packets if they cannot process them in time. Other major packet loss causes include faulty equipment and cable.
How do you calculate packet loss?
Take a count of the number of packets sent at one point on the network and the number of packets received at another node. Subtract the number of packets received from the number of packets sent and divide the result by the number of packets sent to get the packet loss rate.
Why do I have packet loss with Ethernet?
Ethernet cables will lose packet is there is heavy electromagnetic interference nearby, if part of the cable is damaged or if the connectors at each end are loosely plugged into equipment.
Being able to easily remedy unforeseen buildup in packet loss will greatly assist you in performing your job well. Although the tools on this list are a little pricey, they pay for themselves in the long run through productivity increases and lower bandwidth requirements.
Fortunately, all of those expensive tools we outlined above are available for free trials. Check out a few to see which gives you the best opportunity to prevent or reduce packet loss in your network.
Have you experienced overwhelming levels of packet loss that impacted your network performance? Do you find that overloading occurs frequently on your network? Which tools do you use to monitor your network and prevent dropped packets? Leave a message about your experience in the comments section below, and help others in the community learn from your experience.