The article "The Size of Packets" explores the distribution of IP packet sizes on the internet, emphasizing the enduring prevalence of small packets despite increasing bandwidth. It analyzes data from various sources, highlighting that the median packet size remains stubbornly around 400-500 bytes, even on high-speed links. This challenges the assumption that larger packets dominate modern networks and underscores the importance of optimizing network infrastructure for small packet efficiency. The piece also delves into the historical context of packet sizes, touching on Ethernet's influence and the continued relevance of TCP/IP headers, which contribute significantly to the overall size, especially for smaller payloads.
This comprehensive blog post, titled "The Size of Packets," delves into the intricate world of data packet sizes as they traverse the internet. The author, Geoff Huston, meticulously explores the evolution and current state of packet sizes, emphasizing the complex interplay between various factors that influence these sizes. Beginning with a historical overview, the post highlights the shift from earlier networks with relatively uniform packet sizes to the contemporary internet, characterized by a highly diverse and dynamic distribution of packet sizes. This diversity stems from the multitude of applications and protocols vying for bandwidth, each with its own optimal packet size considerations.
Mr. Huston elucidates the impact of various protocols, including TCP, UDP, and QUIC, on packet size determination. He underscores the role of TCP's congestion control mechanisms, which dynamically adjust packet sizes to respond to network conditions, thereby optimizing throughput while mitigating congestion. The discussion extends to the influence of the Path Maximum Transmission Unit (PMTU), a critical parameter that limits the maximum size of a packet that can be transmitted without fragmentation along a given network path. The intricacies of PMTU discovery and its impact on performance are thoroughly analyzed.
Furthermore, the post explores the rising prevalence of encrypted traffic and its implications for packet size distributions. The addition of encryption headers inevitably increases packet sizes, and this effect is carefully considered in the analysis. The author also scrutinizes the distribution of packet sizes across different network vantage points, contrasting observations from the "edge" of the network, closer to end-users, with those from the "core" of the network, where traffic is aggregated. These comparisons reveal valuable insights into how packet sizes are shaped by network infrastructure and user behavior.
Finally, the post provides a detailed examination of recent trends in packet size distributions, drawing upon extensive data analysis. It reveals a notable increase in the prevalence of smaller packets, a phenomenon attributed to the growing popularity of mobile devices and the increasing adoption of protocols like QUIC, which are designed for efficiency in mobile environments. The author concludes by speculating on the future trajectory of packet sizes, acknowledging the ongoing evolution of network technologies and applications and their continuing influence on this fundamental aspect of internet communication. He suggests that understanding these trends is crucial for network operators and application developers alike, enabling them to optimize performance and efficiency in the ever-evolving digital landscape.
Summary of Comments ( 28 )
https://news.ycombinator.com/item?id=43723884
HN users generally agree with the article's premise that smaller packets are better for latency. Several commenters note the importance of considering protocol overhead when discussing packet size, particularly in the context of VoIP and gaming where latency is critical. Some point out the trade-off between smaller packets (lower latency) and larger packets (higher throughput), suggesting that the "optimal" packet size depends on the specific application and network conditions. One commenter questions the article's dismissal of jumbo frames, arguing they can be beneficial in certain scenarios like data centers. Others offer additional resources and technical explanations regarding packet fragmentation and reassembly. A few commenters discuss the historical context of packet size, referencing older protocols and network limitations.
The Hacker News post "The Size of Packets" (https://news.ycombinator.com/item?id=43723884), which links to an article discussing internet packet sizes, has a moderate number of comments that delve into various aspects of networking and performance.
Several commenters discuss the historical context of packet sizes and the evolution of network technology. One commenter highlights the limitations of early Ethernet, which had a maximum transmission unit (MTU) of 1500 bytes, and how this influenced the common packet size seen today. Another points out that the introduction of jumbo frames, which allow for larger packets, aimed to improve efficiency but faced adoption challenges due to fragmentation issues and inconsistent support across networks. The complexities of balancing larger packet sizes for efficiency against the potential for increased latency and retransmissions due to errors are explored in several comments.
The topic of network overhead is also raised, with commenters discussing the proportion of a packet dedicated to headers versus actual data. The impact of different protocols, such as IPv4 and IPv6, on packet overhead is mentioned. One commenter provides specific calculations showing the overhead percentages for various scenarios, highlighting the significance of this overhead, especially with smaller packets.
Performance implications are a central theme. Some comments discuss the relationship between packet size, latency, and throughput, acknowledging that larger packets can reduce overhead and improve throughput but also increase latency in certain situations. The practical challenges of tuning network parameters to optimize for specific applications are also acknowledged.
Security considerations are briefly touched upon. One commenter points out that smaller packets can be beneficial for security in some contexts by reducing the impact of a single lost or corrupted packet.
Finally, a few comments offer anecdotal experiences and observations related to network performance and packet sizes in different environments. One commenter shares an experience with satellite internet where smaller packets were found to be more reliable, illustrating the real-world impact of these technical details.
Overall, the comments provide a range of perspectives on the nuances of packet sizes and their implications for network performance and efficiency. They highlight the ongoing balancing act between maximizing throughput while minimizing latency and ensuring reliability in diverse network environments. The discussion is grounded in technical details but also incorporates practical experience and historical context, offering a valuable supplement to the linked article.