Skip to content Skip to navigation Skip to footer

What is Packet Loss?

Packet Loss Definition

Network packets, or just packets, are small units of data transported over a network. All internet communication activities involve packets, including sending and receiving emails, downloading web content, streaming videos, and listening to podcasts. 

Packets are sent to their destinations along the best path possible to ensure network efficiency. A network that is configured properly and optimally can more evenly distribute its load across several pieces of hardware, enhancing performance and delivering a seamless experience for end-users.

Most internet users are blissfully unaware of packets. However, when a file refuses to download properly or a video has issues playing, users become concerned and usually get IT involved to investigate. The issue might be packet loss. 

But what is packet loss, exactly? 

When connecting the internet or networks units of data called packets begin to be sent out and received between a router and the device. When a packet or more fails to travel between the router and the device this is when a packet loss occurs. The farther the packets have to travel, the higher the chances of loss.

Packets that do not get through properly are a drain on the entire network, driving down network speeds and throwing off a network's throughput and bandwidth. Packet loss can also have economic consequences. Aside from having to spend on additional IT equipment and bandwidth to accommodate the lag, organizations can suffer from lower productivity because employees might be unable to carry out their everyday tasks on the job. 

According to Gartner, the average cost of IT downtime is $5,600 per minute. At scale, this can escalate to as much as $140,000 per hour on the low end to as much as $540,000 per hour on the high end. Indeed, packet loss can have negative economic effects on the enterprise.

What Causes Packet Loss?

Let us look at several factors that can cause packet loss:

Network Congestion

This is the most common cause of packet loss. Network congestion, as its name implies, is like congestion you would find on a highway. Cars on an eight-lane highway might be traveling at normal speeds, but during peak times, the number of cars on the same highway could triple, even quadruple, preventing them from traveling at their normal speeds and slowing everyone down. An exit, or when lanes merge, could cause further slowdowns.

It is the same with network traffic. When network traffic reaches maximum capacity, some packets will invariably need to wait. Unfortunately, a connection can only handle so much, and packets are the first things to get abandoned when a network plays catch-up. Fortunately, software today is programmed in such a way that it tries to go back for "lost" packets by resending the data or reducing transfer speeds in order to give each packet an opportunity to travel through the network.

Problems with Network Hardware

Aging, outdated hardware in the form of firewalls, network routers, and switches could affect network performance and cause packet loss. Older endpoints, including older models of smartphones and laptops used by employees, can also cause packet loss. Older devices, with outdated chipsets, could hog power and cause bottlenecks in the network.

Software Bugs

Bugs might also cause packet loss. They usually appear in older versions of software and can cause issues with file transmission. For example, the size of a Word document created with an older version of Word might be larger than it would be had the creator used a newer version of the application. This could slow the document's transfer and cause packet loss.

Software Threats

Packet loss can also occur as a result of a security breach. Cyber criminals have figured out a way to launch something called a packet drop attack. In this type of breach, a cyberattacker takes control of a router and sends instructions that drop packet data into a stream. When an organization experiences an unusually high rate of packet loss across a network in a very short amount of time, it is possible that a packet loss attack is underway.

Overloaded Devices

With so many online services running and apps launched simultaneously, a device might simply be overloaded. At scale, with hundreds, if not thousands, of devices connected to the network all at the same time, the entire network might be operating at a capacity level it was not initially designed to accommodate.

Packets on overstressed devices sometimes arrive at their intended destinations. But by then, the network might already be too vulnerable to process the packets and send them back out. Many devices have temporary storage to keep packets in a holding pattern until they can be sent out. Of course, even this resource can quickly get overwhelmed, leading to excess packets being dropped.

Wired vs. Wireless Networks

Data traveling over a Wi-Fi connection can suffer from packet loss much more frequently than that via a wired connection. Unfortunately, with so many remote employees working from home and from disparate locations, data that once was shared via a wired corporate local-area network (LAN) or wide-area network (WAN) is now entering the corporate network via a wireless connection to the public internet. As such, networks can quickly become overwhelmed, leading to packet loss.

Faulty Configuration

Something as simple as a faulty network configuration can cause packet loss. As companies merge and divest assets, and as full-time IT staff positions become outsourced, network configurations may fall by the wayside. It may also be that aging network equipment cannot handle more modern network management protocols, such as network automation and software-defined wide-area networking (SD-WAN).

What Does Packet Loss Mean for Users?

For most users, packet loss comes in the form of a slow document download, frozen video, or a garbled Voice over Internet Protocol (VoIP) call. Packet loss will generally reduce the speed or throughput—the actual amount of data that flows through the network—of a given connection. 

The term latency is a general term referring to many types of delays typically found in the processing of network data. Packet loss is one type of latency. 

Packet loss affects different applications differently. Packet loss may be no bother for some users when it comes to simple document downloads. For example, a 10% packet loss, resulting in an extra second added to a 10-second document download, may not cause much frustration. However, in other applications, even a smaller packet loss, such as 2%, can result in a noticeable and unpleasant reduction in the quality of a streaming video or voice call. 

Packet loss might even increase the central processing unit (CPU) load to process the additional network overhead. This is why newer models of hardware are needed to handle larger volumes of network traffic.

How to Diagnose Packet Loss

Packet loss can be diagnosed with two words: network monitoring. Network monitoring can rapidly and reliably determine the reasons behind packet loss in the enterprise. Let us take a look at a few examples. 

Example 1

During a Zoom call, the call quality deteriorates to the point that you cannot continue with the call. However, a few minutes later, you try placing a call using Google Meet, and all is fine. While this does not represent a formal monitoring assessment for packet loss, you can deduce that the way each communications vendor transmits data over the internet is different, and the route that the packets take differs significantly.

Example 2

Employees and customers accessing data stored on a server in one location do not experience any interruptions, yet other employees and customers accessing data stored on another server in another location are experiencing long delays. Of course, to everyone, the user experience—whether as an employee or a customer—should be identical regardless of the location. The second server's connection problems likely indicate high packet loss and an issue with the network connection that needs to be addressed immediately.   

Several tests exist to determine the performance of your network. One is the ping test, which measures the amount of time it takes for a round-trip Internet Control Message Protocol (ICMP) packet, or ping, to reach and then return from a certain destination. Deep packet inspection (DPI) is a comprehensive and significant way of investigating and measuring private network traffic by locating and examining the packets for anomalies.

How to Stop Packet Loss

It is important to note that there is no options for 100% prevention of packet loss, meaning there can only be a reduction of packet loss stemming from preventative measures, but zero packet loss is impossible. This is because the causes of packet loss, such as an overloaded system, can never be completely eliminated. Systems and networks keep growing larger and larger, so engineers and IT staff can only do their best to address the increasing problem.

Restart Your System

Rebooting not just employee devices or endpoints but also the routers can help. Often, when a system reboots, software is updated, temporary files are deleted, and additional memory becomes available.

Check Network Connections

Make sure that your network is configured properly. Even a single cable that is not plugged in correctly can cause packet loss. Further, another look at the network's multiprotocol label switching (MPLS), which is a protocol designed to get data packets to their destinations quickly, might be necessary.

Use Cable Connections Instead of Wi-Fi

Since packets are more likely to get lost via Wi-Fi, check whether a wired, Ethernet connection will fix the issue, but it's a temporary solution at best.

Update or Upgrade Your Software

Updating your operating system (OS) and your most used programs will also help. The most recent version of an OS is less likely to have bugs, which means there is a lower likelihood of packet loss. Lean on the hard work of the dozens, if not hundreds, of engineers working for software vendors such as Apple, Microsoft, and Mozilla, who fix errors on an ongoing basis to improve your computing experience.

Replace Old Hardware

Sometimes older hardware can be an issue. This goes for employee endpoints as well as the firewalls, network switches, and routers that make up your network infrastructure. Determine whether an older and possibly faulty piece of hardware on the network is causing packet loss and replace it with a new one.

Use QoS Settings

Quality of service (QoS) settings help manage packet loss by organizing network resources. QoS settings will assign more network traffic to the places that can best accommodate more resource-intensive data, such as voice and video.

Strengthen Security

As mentioned above, a security threat can cause packet loss. As a preventative measure, organizations and certainly remote employees working from home can strengthen their security posture to prevent a cyberattacker from taking control of a router and carrying out a packet drop attack. Updating the security settings on a router, using a virtual private network (VPN), turning on encryption, and using strong passwords—and changing them frequently—can help.

How Fortinet Can Help

Network monitoring is the go-to strategy for maintaining the strength of your network environment. A regular device scan can confirm that your network is capable of accommodating increasing capacity and that your system has defenses in place to prevent data loss.

FortiClient offers next-generation endpoint protection, monitoring, and assessment of endpoint risks. It can also determine whether there are network issues causing packet loss. The Fortinet Secure Web Gateway (SWG) technology is another line of defense against packet loss. Because it filters unwanted software, including malware, from user-initiated internet connections, packet loss due to security threats is minimized.