SPDY Brings Responsive and Scalable Transport to Firefox 11

That's fantastic news re nginx! The last I heard was that they were evaluating it and it's good that they are now committing to deliver support for SPDY.

Is Apache mod-spdy useful yet? The project page says "still an early beta and is not yet suitable for production environments" and everything I've read elsewhere says it's not ready. But things have a way of moving fast, is that outdated info?

To address some of your points:

- pipelining is still single-file request-response though. With SPDY, you can send multiple requests at once, and the server responds to them in whatever order it likes.

- The point of removing the FIFO queuing is that the server can start responding with simple files before the more expensive resources are calculated. Usually the HTML itself can take a while to be generated server-side, where as CSS and JS files are usually just served straight off disk.

In a FIFO model, the 200ms the client is waiting for the HTML to be generated is just wasted. You could be using that time to be downloading CSS or JS or images, etc.

- There's two options for server-initiated requests in SDPY. One where the server says "Since you requested this resource, you'll probably also want this, this, and this." (i.e. it sends links to the client with the related resources). Other other option is where it actually says, "Since you request this resources, here's these other resources you might be interested in as well."

In the first case, the client can begin processing those other files (e.g. checking it's local cache or actually making a request for them) before the original resource has completed downloading/parsing. In the second case, it could be that the original resource and the "sub-resource" (e.g. HTML file and attached CSS file) have similar caching rules, so if a client requests one it's likely that it'll request the other anyway.

- SDPY also has options for not including those kinds of things (e.g. User-Agent, Host, Accept-*) on every request. But even when you do that, compression still has benefits. Even once you've removed all the redundant data, compression will still help, so why wouldn't you?

- I agree there's certain kinds of content which don't benefit greatly from compression. But on almost all platforms, CPU power is much higher than network capacity. In fact, I can't think of a single platform where that's not the case...

Http pipelining is quite different. When the server takes a long time to respond to a single request, it stalls the entire pipeline. To efficiently use parallelism you have to start multiple http tcp connections, but that is less efficient than a single connection because they all have to slow start.

As for header compression, have you checked how large headers are these days? They can easily be 1.5 kb.

- Pipelining would be pretty cool if it worked. There are a number of problems with it: * head of line blocking * transparent proxies that don't support pipelining properly * error detection - FIFO queuing: Why is the client in a better position to know in what order the page needs to be rendered than the server? Isn't the server the one that knows all the resources that need to be sent to the client? - Client initiated request: Yeah, server push is a complicated area. But there are some cases where server push is clearly superior. For example, data URI inlining ruins cacheability. It's better to server push an already cached resource that can be RST_STREAM'd than inline a resource and make it larger and uncacheable. - While we'd like to get rid of headers as much as possible, it's still impractical to completely eliminate headers like User-Agent. - SPDY does not force data compression, and optional data compression has been removed in draft spec 3.

which is to be expected with a TLS connection. OTOH you get to drop all the extra TCP handshakes, you get better congestion control, you get header compression, and that encrypted connection is often a really good thing.

http://bitsup.blogspot.com/2011/09/spdy-what-i-like-about-yo...

But yes, there remains no silver bullet, and you'll have to pick the right tool for the job.

It looks like SPDY will/could support proxies: http://www.chromium.org/spdy/spdy-proxy http://dev.chromium.org/spdy/spdy-proxy-examples

Wouldn't this be solved by sending a Cache-Control: public, max-age=<long-duration-in-seconds> header so that the assets can be stored in ISP proxy caches as well as browsers on-disk caches

It may be not difficult to do lazy image loading in javascript but ideally you wouldn't have to do it at all. It doesn't encourage lazy or shoddy work. it just allows web developers to focus on creating value rather than just figuring out how to efficiently load images. It's kind of like the argument that garbage collectors are bad because encourage people to use memory inefficient designs, when in fact the reason that garbage collectors are good is because it allows you to focus on more important problems (like design and features). Sure every tool has a different way to shoot yourself in the foot but that doesn't mean you shouldn't use the tool.

tl;dr If SPDY lets me write a website without worrying about how many elements are loading at a time then ill have more time to spend on actually building a product.

  You can do lazy image loading in just a few lines of javascript, without jquery. Scripts can be deferred, etc.

Those are hacks. I'd rather have a browser that loads stuff really fast and not have to jump through hoops like spriting, etc. If you're really concerned about deferring the loading of images, that could also be a feature of the browser.

Also, consider that asking the question, "why the heck would anyone develop a website that loads that many elements all at once," is like asking, "why the heck would anybody develop a program that doesn't fit on a 1.44MB floppy?".

> why the heck would anyone develop a website that loads that many elements all at once?

I just opened my G+ page and count 50+ user thumbnails. Many modern social websites have lots and lots of small unique user-specific images.

You can do a lot of things, but why not just speed up the base functionality? Lazy-loading of images speeds up the experience over HTTP, and it will also speed up SPDY. There's only so much optimization you can do at the highest level. At some point, you need the lower levels to just go faster.

Spdy is not great.

For instance header compression using a shared prefix dictionary saves only a handful (~100 bytes) over TLS compression -- worthless, not to mention it's already had several versions of the prefix dictionary.

Spdy developers didn't even test against HTTP tunneling, which in practice as seen in current Firefox and Opera works just as well. The 'head of line blocking' is not a big deal in practice.

Why? AFAICS, SPDY is open and available for everyone who wants to implement it.

What's so bad about companies making it open, free and open source, thus contributing to a better Internet experience for everyone? No one limited SPDY to Google sites - Microsoft and Yahoo are free to implement it for their servers and enjoy browsing speedups with Chrome and (soon) Firefox 11.

Mozilla refused to implement NaCl and WebP; it looks like they're evaluating Chrome features on a case-by-case basis.