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Jitter is a sneaky problem that ruins the experience of live streaming. It lurks in the shadows, manifesting as missed video frames, stuttering audio, crackling voices, or that missed game-winning shot when your ping suddenly spikes.
A common definition of jitter in network streaming is: unpredictable changes in network latency. In our upcoming series, “Fighting with Jitter,” we’ll embark on a journey to understand this mysterious adversary. First, we’ll unmask its true nature and learn how to uncover its cloak of invisibility. Then, we’ll gear up with tools and strategies to manage it effectively. Spoiler alert: we won’t completely defeat jitter, and we won’t make peace with it either. The real world isn’t a cartoon where problems disappear. Instead, we’ll learn to manage jitter so it doesn’t scare us anymore.
Where does jitter have the biggest impact?
How does it sneak into your network and cause trouble? Let’s figure it out step by step. And speaking of steps, let’s begin by looking at the battlefield: network streaming. This is where jitter causes the most trouble.
The diagram shows how jitter and bandwidth impact two types of network streaming: static media and live media. For static media like YouTube, Netflix, and Spotify, jitter isn’t much of a problem. These platforms handle delays by preloading media before playback, a process known as buffering. This ensures smooth playback even with low bandwidth by storing data in advance. However, live media such as video calls, gaming, and AI-generated content faces a different challenge. Here, low latency is critical, and small buffers make these streams highly sensitive to jitter. In live media, jitter causes stuttering, lag, and interruptions, making it the biggest obstacle to smooth performance.
Is jitter truly unpredictable?
Even if it can appear so from the perspective of the end user, Jitter in a network is not entirely random. Jitter refers to the variation in packet arrival times during data transmission. While some of this variation may seem unpredictable, it is usually caused by specific factors within the network, such as:
- Network Congestion: High traffic volumes can lead to delays in some packets as they wait in queues at routers or switches.
- Routing Changes: Packets may take different paths through the network, causing variations in travel time.
- Hardware or Processing Delays: Devices like routers and switches introduce delays due to processing time, which can vary depending on workload.
- Queuing Mechanisms: When multiple packets arrive at a router simultaneously, some are queued while others are forwarded, leading to uneven packet delivery times.
- Interference or Noise: In wireless networks, signal interference and environmental factors can cause variations in packet transmission.
- Network Protocols: Some protocols introduce delays due to retransmissions, acknowledgments, or error correction mechanisms.
While these factors are deterministic in nature (i.e., they have specific causes), their interaction can create complex patterns of delay that may seem random without detailed analysis. Advanced tools can be used to identify and measure these patterns to better understand and mitigate jitter.
Can a Simple IT Enthusiast Take on Jitter?
Of course, controlling major root causes of jitter primarily falls within the domain of network providers. The 5G standard takes latency and jitter very seriously, as highlighted in this article. Additionally, initiatives like the GSMA Open Gateway and CAMARA aim to provide developers with APIs to access network performance data, including metrics like latency and jitter. While these APIs are still in development and not yet widely adopted, they show promise for future use (source).
Even though you might not be able to control jitter directly at this time, understanding how it can impact your solution allows you to take proactive steps. By employing techniques to measure jitter and mitigate its effects, you can still enhance the user experience, even without full access to the developing APIs.
So, Jitter Unmasked. What's Next?
Jitter, the not enitrely unpredictable variation in packet arrival times, disrupts live streaming, gaming, and other low-latency applications by causing stuttering, lag, and interruptions. While network providers and emerging 5G APIs play a key role in addressing its root causes, IT enthusiasts can still measure and mitigate jitter's impact. By understanding its sources—such as network congestion, routing changes, and interference—proactive strategies can be applied to enhance user experiences, even in the face of this persistent network challenge.
In the next article of this series, we’ll explore how jitter affects packet flow in media streaming, introduce tools for measuring it, and dive into a case study. We'll measure a couple of realistic network connections using the iperf3 network measurement tool and then simulate jitter with the tc (Traffic Control) tool. Excited? We are too! :)
