TCP and the Lower Bound of Web Performance

Web Performance 209/210
Average rating: ****.
(4.77, 35 ratings)

This talk begins with the physics of network latency as explained in Cheshire’s famous paper “Its the Latency, Stupid.” Then I review the basic TCP algorithm and its history up to 1986, when the nascent internet experienced a series of congestion collapse events. I explain the nature of congestion collapse, and Jacobsen’s research which led to the creation of TCP slow start and congestion control in general. Finally I explain how TCP’s congenstion control algorithms impact web application latency, and give some general guidelines for application design that result from these observations.

Photo of John Rauser

John Rauser


John has been extracting value from large datasets for 15 years at companies ranging from hedge funds and small data-driven startups to retailing giant He has deep experience in the areas of personalization, business intelligence, website performance and real-time fault analysis. An empiricist at heart, John’s optimism and can-do attitude make “Just do the experiment!” his favorite call to arms.

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Picture of Mike Bailey
Mike Bailey
07/09/2010 1:34am PDT

Your talk inspired me to plot some real world measurements. I measured the time taken to load 200 files (1-200KB) from two locations (AU and US). The results show the huge impact latency has on load times.

Chetan Ahuja
06/25/2010 9:53am PDT

Now that I look at the pdf, it captures the “animations” that I was referring to. Thanks a lot. Great deck that I’m sharing with

Larry Liu
06/25/2010 9:05am PDT

Thanks, John!

Picture of John Rauser
John Rauser
06/25/2010 8:56am PDT

Actually, I use very little animation in my decks (it’s usually both fussy and distracting), so hopefully the PDF will be what you’re looking for.

Chetan Ahuja
06/25/2010 8:48am PDT

PDF’s would be great. Not to be greedy/pushy, but for that particular presentation—the animations/progressions were quite valuable and PDF conversion would lose that component. But still, preparing those slides quite clearly involved a lot of hard work. Thanks a lot for sharing it with us.

Picture of John Rauser
John Rauser
06/25/2010 8:27am PDT

Hello all. I’m glad you enjoyed the talk. I’ve sent a PDF of my slides to the good folks at O’Reilly and they should post them here soon.

Larry Liu
06/25/2010 7:18am PDT

The notes of this session is on any url?

Picture of Tom Croucher
Tom Croucher
06/25/2010 3:11am PDT

This was the best talk of the conference for me. Great information and very well presented.

Picture of Jake Brutlag
Jake Brutlag
06/24/2010 9:42am PDT

A clear, concise, entertaining presentation of a complex topic that is very relevant to web performance.

Chetan Ahuja
06/24/2010 4:41am PDT

Great session yesterday. One of the best of the conference. Would really really love to get my hands on the slides.

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kathy allen
06/23/2010 3:51pm PDT

kick ass

Picture of Daniel Lamb
Daniel Lamb
06/23/2010 11:13am PDT

My fav session today! Fantastic! Inspired me to optimize more for TCP.

Picture of Roman Fuchs
Roman Fuchs
06/23/2010 10:56am PDT

Excellent talk! Thanks for wrapping up the day so nicely!

Picture of Steve Souders
Steve Souders
05/18/2010 4:24am PDT

I met John years ago. He’s the Freakonomics person in web performance – always analyzing data and finding interesting insights. John’s a great speaker, so I’m looking forward to this talk. Also, the actual topic is critical. I’m seeing more and more web publishers focusing on TCP optimizations, and even startups focusing on this area of performance optimization. People interested in this talk should also checkout Tom’s I Made a Map of the Internet workshop.

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