What is Latency? KB ID 0001874

What is Latency?

I hear people use the word ‘Latency‘ a lot, mostly without ever really understanding what it is, unlike its close relations bandwidth and thoughput* which are measurments of data, latency is a measurment of TIME, and in a lot scenarios is variable depending on what’s happening.

*Note: Too low bandwidth and thoughput can increase latency.

There will always be latency, becasue we are bound by the laws of physics, to pass a ‘light pulse’ down a fibre optic cable from London to Paris, will take less time than it will to pass that same lightpulse from London to New York. We call this propogation delay.

1. Propagation Delay: This is the time it takes for a signal to travel from the sender to the receiver through the physical medium (such as fiber optics or copper cables). The speed of propagation is close to the speed of light but can vary slightly depending on the medium.
2. Transmission Delay: This is the time required to push all the packet’s bits onto the wire. It is influenced by the size of the packet and the transmission rate of the network.
3. Processing Delay: This is the time taken by network devices like routers and switches to process the packet header and make forwarding decisions. Processing delays are generally very small but can add up across multiple devices.
4. Queuing Delay: This occurs when a packet waits in a queue before it can be transmitted. Queuing delays can vary significantly depending on the network congestion and the configuration of the network devices.
5. Propagation Distance: The physical distance between the source and destination plays a critical role in latency. Longer distances naturally result in higher latency due to the increased time it takes for signals to travel.
6. Network Congestion: High traffic volumes can cause congestion in the network, leading to increased queuing delays and, consequently, higher overall latency.
7. Bandwidth and Throughput: Although bandwidth is the maximum rate of data transfer, actual throughput can be lower due to various factors, including network congestion and overheads. Lower throughput can contribute to higher latency.
8. Protocol Overheads: Different network protocols have various overheads associated with them. For instance, the Transmission Control Protocol (TCP) has higher overhead due to its error-checking and recovery features compared to the User Datagram Protocol (UDP).
9. Hardware and Software Limitations: The performance of network hardware (like routers, switches, and network interface cards) and software (such as drivers and network stacks) can impact latency. Faster and more efficient hardware and software reduce latency.

Latency is typically measured in milliseconds (ms) and can be assessed using various tools and techniques, such as ping tests and traceroute commands. Lower latency is especially crucial for applications requiring real-time interaction, such as online gaming, video conferencing, and financial trading systems.

Minimizing network latency involves optimizing network infrastructure, improving hardware and software efficiency, and ensuring adequate bandwidth and throughput to handle the expected traffic load.

What is Latency and Why is this Important?

Well the complaint is nearly always “We are experiencing latency issues“, usually when the ‘users’ are having performance issues with ‘something’. Now sometimes the problem IS the network (shock & horror). But all the bandwidth/Thoughput and Low latency in the worlds will not help you if you have a poorley coded application, or your DNS is not seup correctly.

But it’s not just old and poorley coded applications that require low latency Some application platforms we take for granted can suffer for example.

1. Online Gaming: Real-time multiplayer online games require low latency to ensure smooth gameplay and quick reactions. High latency can result in lag, making the gaming experience frustrating and uncompetitive.
2. Video Conferencing: Applications like Zoom, Microsoft Teams, and Skype require low latency to facilitate real-time communication. High latency can cause delays, leading to awkward conversations and reduced communication quality.
3. Voice over IP (VoIP): Services like Skype, WhatsApp, and other internet-based telephony services need low latency to provide clear and immediate voice communication. High latency can cause echo and delays, making conversations difficult.
4. Financial Trading: Stock trading platforms and high-frequency trading systems rely on low latency to execute trades in milliseconds. Even minor delays can result in significant financial losses or missed trading opportunities.
5. Telemedicine: Remote medical consultations, surgeries, and other healthcare services often require low latency to ensure accurate diagnostics and timely intervention.
6. Augmented Reality (AR) and Virtual Reality (VR): AR and VR applications need low latency to provide immersive and responsive experiences. High latency can cause motion sickness and degrade the user experience.
7. Industrial Automation and Control Systems: Manufacturing processes, robotics, and other industrial applications require low latency for precise control and real-time monitoring to ensure safety and efficiency.
8. Autonomous Vehicles: Self-driving cars and drones rely on low latency for real-time data processing and decision-making to navigate safely and respond to dynamic environments.
9. Cloud Gaming: Services like Google Stadia, NVIDIA GeForce Now, and Xbox Cloud Gaming stream games from the cloud to users’ devices. Low latency is critical to provide a responsive gaming experience comparable to playing on a local console or PC.
10. Smart Grids: Advanced electrical grid systems require low latency for real-time monitoring and control to manage power distribution efficiently and respond to fluctuations in demand and supply.
11. Remote Desktop Applications: Tools like Remote Desktop Protocol (RDP) and Virtual Network Computing (VNC) require low latency to provide a seamless and responsive experience when accessing and controlling a remote computer.
12. Live Streaming: Interactive live streaming platforms like Twitch and YouTube Live require low latency to ensure minimal delay between the broadcaster and viewers, enabling real-time interaction through chat and other features.

Ensuring low latency for these applications often involves optimizing network infrastructure, using efficient communication protocols, and sometimes deploying edge computing to process data closer to the source.

Related Articles, References, Credits, or External Links

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