[sargun]

The biggest thing that companies miss when they're building SaaS applications is that the network fucking matters. I'm talking from a internet-connectivity perspective. The view here is that you can take any ol' 'enterprise' ISP and put your servers on it, and you'll be good to go.

Unfortunately, no two ISPs are equal, which often times, forces you to purchase from both. TCP implementations of OS's today have been tuned for the late 90s, which requires dives under the hood to tune them for today's TCP.

When your application performance is pegged on the network the, most people say just put static content on a CDN - and that works. But for dynamic content, most people think you're screwed. While you can't main any gigantic gains on it, there are a few things you can do for speed: TCP tuning, compression, path optimization, and pipelining.

[Terretta]

> TCP implementations of OS's today have been tuned for the late 90s,

Here's where you need to slow down and think for a moment before you re-invent TCP.

If you "retune" everything for broadband, you're crippling your ability to reach your emerging mobile audience, whose TCP metrics look for all the world like dial up and ISDN of the late 90s.

[moe]

Actually they don't. Dial-up is low bandwidth, low latency. Mobile is high bandwidth, high latency.

[Terretta]

Dial up is low latency when a modem adds 200 ms by itself?

Mobile is high bandwidth when an EDGE connection might pull 110 Kbps when the rural user is lucky?

Either you're confused, or talking about different tech.

[moe]

Dial up is low latency when a modem adds 200 ms by itself?

Closer to 100ms and, more importantly, constant not variable.

Mobile is high bandwidth when an EDGE connection might pull 110 Kbps when the rural user is lucky?

The fastest modems sold were 56kbps.

[Terretta]

I had ISDN in the 90s, at dual 64k.

Was in ISP business since early 90s, and in streaming business since before broadband, so familiar with connection profiles, latency, and effects of tuning TCP. There's a lot of lost or forgotten art being reinvented or rediscovered for today's mobile.

[mnutt]

Are there any up-to-date resources you could recommend for TCP tuning?

[sargun]

I would look at Google's papers regarding TCP tuning mostly. They're very well written with some real-world data.

What kind of applications are you creating?

[mnutt]

Thanks! I'll check those out.

We've built an app that dynamically generates images and serves them up inside of emails. People skim through emails pretty quickly so it's important that the images load as quickly as possible. And we usually can't use a CDN since the images are often personalized for each user. The images vary in size, but for the smaller images I'd like to see if slow-start tuning could help.

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