Packet Loss

Packet Loss (Taken from https://www.minitool.com/lib/packet-loss.html)

What is a Packet?

Before we get into packet loss, let’s unpack what packets are. Packets, or network packets, are small units of data carried over a network. Everything you do on the internet, from sending emails to downloading gifs, is made up of packets. Packets are sent to their destinations along the most sensible path to maintain network efficiency. By doing this, the network can more evenly distribute its load across many pieces of equipment, which enhances performance.

What does Packet Loss mean?

Packet loss refers to the number of data packets that get lost or are dropped during their travel across a computer network before reaching their destination.

Oftentimes, packets don’t successfully make it through the network to their destination. Internet packet loss, sometimes called latency, occurs when packets get lost in transit during their voyage. Wi-Fi packet loss is likely to occur in private, wireless networks because when things are sent through the air, it’s easy for them to get lost or dropped. This becomes even more likely on long-distance internet connections because the packets have farther to go and, by extension, more room for error.

Unsuccessful packets slow down network speeds, cause bottlenecks, and throw off your network throughput and bandwidth. Packet loss can also be expensive. If you don’t do all you can to cut down on packet loss in your system, you’ll have to spend a lot of money on extra IT infrastructure and more bandwidth to accommodate the lag.

What causes Packet Loss?

Packet loss can be caused by a number of issues, but the most common are:

Network Congestion

Network congestion, as its name suggests, occurs when a network becomes congested with traffic and hits maximum capacity. Packets must wait their turn to be delivered, but if the connection falls so far behind that it cannot store any more packets, they will simply be discarded or ignored so that the network can catch up. The good news is that today's applications are able to gracefully handle discarded packets by resending data automatically or slowing down transfer speeds.

Software Bugs

Software bugs are another common cause of packet loss. If rigorous testing has not been carried out or bugs have been introduced following software updates, this could result in unintended or unexpected network behavior. Sometimes rebooting can resolve this issues, but more often than not the software will need to be updated or patched.

Problems with Network Hardware

Faulty or outdated network hardware such as firewalls, network switches and routers can slow down network traffic considerably. As a company grows and starts to experience lag, packet loss and total connectivity drops, this hardware needs to be revised and updated so that it can manage the growing throughput.

Security Threats

In addition to problems with software and hardware, packet loss can also be caused by a security breach. One such attack that has become popular with cybercriminals in recent years is the packet drop attack. During an attack, a malicious user takes control of a router and sends commands that drop packets into a stream of data. If you suddenly notice high rates of packet loss across your network, it could be a cyber attack in progress.

Causes of Packet Loss (Taken from https://www.comparitech.com/net-admin/how-to-fix-packet-loss/)

What are the Effects of Packet Loss?

Packet loss affects different applications in different ways. For browsing and downloading data files, it will cause slowdowns. In many cases, the slowdowns may not be noticeable, as a 10% packet loss might just add 1 second to a 10 second download if you are working with a low-latency link. If the packet loss rate is higher, or there is high latency (like when browsing a website internationally) it can cause the slowdowns to be worse. For example: If you have 10% loss and 500ms of latency, a normal 10 second download might end up being over 20 seconds due to the number of packets that need to be retransmitted and the request time to have them re-sent.

For realtime applications like voice and video, the packet loss may be far more severe, as 2% packet loss is typically noticeable to a listener/viewer and can be irritating for conversations to occur without some amount of “what did you say?” questions being exchanged.

The impact of packet loss differs depending on the protocol/application. TCP is typically designed to handle packet loss because if a packet is lost, meaning it wasn’t acknowledged, it will be retransmitted. UDP does not have inbuilt retransmission capability, however, and does not handle packet loss as well. Regardless of the protocol/application, though, too much packet loss is a problem.

Typical examples of packet loss experienced by the end user are performance issues with Voice over IP (VoIP) and video calls. You have likely been on a Skype call or other type of virtual meeting, and there was a noticeable performance issue, like robotic sounding, or missed audio. This was probably the result of packet loss (along with other factors like bandwidth, delay, and jitter).

Example of Packet Loss (Taken from https://help.ea.com/en-sg/help/connection-quality/explaining-packet-loss-in-your-game/)

How to Reduce Packet Loss?

There are a number of ways to reduce of prevent packet loss, such as:

Check Your Connections

First, get rid of the obvious options. Make sure your cables and ports are plugged incorrectly.

Restart your system

If you haven’t turned off your system routers or hardware in a while, now is the time. This might give your network the jumpstart it needs to fix any tiny glitches or bugs.

Try cable connections instead of Wi-Fi

Since everything is connected by Wi-Fi nowadays, packets are more likely to get lost. Using an Ethernet connection instead of Wi-Fi can help move things along. A fiber-optic connection is even better.

Remove anything capable of causing static

Cut off surrounding cameras, devices using Bluetooth, wireless speakers, and headphones. You also might want to temporarily shut down your firewall since it uses a lot of bandwidth, and you shouldn’t be running more than one firewall program at a time.

Update your software

It’s time to stop putting off your software updates. An up-to-date operating system is less likely to have bugs, which inevitably leads to fewer opportunities for packet loss.

Replace out-of-date hardware

The same concept applies to your network infrastructure. Take some time to make sure your hardware is in good shape.

Use QoS settings

Quality of Service (QoS) settings help you manage packet loss by triaging your network resources accordingly. This is especially important if your network transmits resource-intensive data like streamed content, online games, video calls, or VoIP. QoS settings will devote more network traffic to the places that need it.

How is Packet Loss Related to Queuing Delay?

The maximum queuing delay is proportional to buffer size. The longer the line of packets waiting to be transmitted, the longer the average waiting time is. The router queue of packets waiting to be sent also introduces a potential cause of packet loss. Since the router has a finite amount of buffer memory to hold the queue, a router which receives packets at too high a rate may experience a full queue. In this case, the router has no other option than to simply discard excess packets.

In our discussion above, we have assumed that the queue is capable of holding an infinite number of packets. In reality a queue preceding a link has infinite capacity, although the queuing capacity greatly depends on the route design and cost. Because the queue capacity is finite, packet delays do not really approach infinity as the traffic intensity approaches 1. Instead, a packet can arrive to find a full queue. With no place to store such a packet, a router will drop that packet; that is, the packet will be lost.

From an end-system viewpoint, a packet loss will look like a packet having been transmitted into the network core but never emerging from the network at the destination. The fraction of lost packets increases as the traffic intensity increases. Therefore, performance at a node is often measured not only in terms of delay, but also in terms of the probability of packet loss.

If arrival rate (in bits) to link exceeds transmission rate of link for period of time, there are 2 scenarios: 1. packet will queue, wait to be transmitted on link 2. packet can be dropped (lost) if memory (buffer) fills

Citations

• What is packet loss? (2020, March 24). Forcepoint. https://www.forcepoint.com/cyber-edu/packet-loss
• What is packet loss: Definition, causes & top 2 test tools | tek-tools. (2020, December 23). TekTools. https://www.tek-tools.com/network/what-is-packet-loss-and-how-to-fix-it
• How to fix packet loss: Guide and top 5 tools. (2020, July 22). Software Reviews, Opinions, and Tips - DNSstuff. https://www.dnsstuff.com/reduce-packet-loss
• Titus, T. (n.d.). Diagnose and fix packet loss in your network. Total Network Visibility. https://www.pathsolutions.com/blog/diagnose-and-fix-packet-loss
• Queuing delay and packet loss. (2016, April 29). Electronics Post. https://electronicspost.com/queuing-delay-and-packet-loss/
• Queueing delay. (n.d.). ScienceDirect.com | Science, health and medical journals, full text articles and books. https://www.sciencedirect.com/topics/engineering/queueing-delay