Latency

Definition

Latency refers to the delay that occurs in the transmission of data over a network, measured as the time taken for a packet of data to travel from the source to the destination. It is a critical factor in determining the responsiveness and overall performance of networked applications, affecting everything from file transfers to real-time communications.

5 Must Know Facts For Your Next Test

1. Latency can be affected by various factors including propagation delay, transmission delay, queuing delay, and processing delay within routers and switches.
2. In general, lower latency leads to better user experience, especially in applications requiring real-time interaction like online gaming or video conferencing.
3. Latency is measured in milliseconds (ms) and can vary significantly based on network conditions, distance between nodes, and types of connections (wired vs. wireless).
4. Different protocols may handle latency differently; for example, TCP includes mechanisms for retransmission which can introduce additional latency under certain conditions.
5. Latency can be a critical consideration for Quality of Service (QoS) architectures, which aim to prioritize traffic types that are sensitive to delays.

Review Questions

• How does latency impact the performance of real-time applications such as video conferencing?
  • Latency significantly affects the performance of real-time applications like video conferencing by introducing delays that can lead to lag between participants' audio and video feeds. High latency can cause interruptions in conversation flow, making interactions feel disjointed and frustrating. For optimal user experience in video conferencing, it’s essential to minimize latency to ensure that all participants can engage in a timely manner without noticeable delays.
• Compare the effects of latency in file transfer protocols versus streaming applications.
  • In file transfer protocols like FTP, latency primarily affects the time it takes to initiate and complete file transfers, potentially leading to longer wait times if the connection experiences high latency. Conversely, in streaming applications, latency impacts not only loading times but also playback quality; high latency can cause buffering issues or interruptions in viewing. Therefore, while both scenarios suffer from high latency, its implications differ based on the nature of the application being used.
• Evaluate how latency interacts with throughput and jitter in a congested network environment.
  • In a congested network environment, latency tends to increase as packets face longer queuing times and more processing delays. This increase in latency can adversely affect throughput since the effective data transfer rate may decrease as more time is spent waiting for packets to be transmitted. Additionally, jitter can increase due to variable delays among packets arriving at their destination, leading to inconsistent experiences for applications sensitive to timing, such as voice over IP or online gaming. The interplay among these factors highlights the complexity of managing network performance effectively.

Related terms

Throughput: Throughput is the rate at which data is successfully transmitted over a network, typically measured in bits per second, and often contrasted with latency to assess network performance.

Round-Trip Time (RTT):

Round-Trip Time is the total time it takes for a signal to go from the sender to the receiver and back again, encompassing both latency and processing delays.

Jitter:

Jitter refers to the variability in packet arrival times over a network, which can be influenced by latency and impact the quality of real-time applications like audio and video streaming.