A 2x Faster Web

#1

Post by johns » Thu, Nov 12, 2009, 6:23 PM UTC

A 2x Faster Web
blog.chromium.org

Re: A 2x Faster Web

#2

Post by cakeface » Thu, Nov 12, 2009, 6:45 PM UTC

Is this basically an RFC for HTTP version 2?

Re: A 2x Faster Web

#3

Post by nixme » Thu, Nov 12, 2009, 6:47 PM UTC

The whitepaper has more information: http://dev.chromium.org/spdy/spdy-whitepaper

Interesting parts:

- "...make SSL the underlying transport protocol, for better security and compatibility with existing network infrastructure." Won't this break many caching models?

- "...provides an advanced feature, server-initiated streams. Server-initiated streams can be used to deliver content to the client without the client needing to ask for it." Nice, push without comet-style hacks.

EDIT: more items that stand out

- "SPDY implements request priorities: the client can request as many items as it wants from the server, and assign a priority to each request"

From the protocol document: http://dev.chromium.org/spdy/spdy-protocol

- "Content-length is not a valid header"

- "Clients are assumed to support Accept-Encoding: gzip. Clients that do not specify any body encodings receive gzip-encoded data from the server."

- "The 'host' header is ignored. The host:port portion of the HTTP URL is the definitive host." I guess this supplants the need for SNI support. Edit: No it doesn't since SPDY sits above SSL. The host isn't known until the secure link has already been established.

Re: A 2x Faster Web

#4

Post by timf » Thu, Nov 12, 2009, 6:49 PM UTC

cakeface wrote: post #2

Is this basically an RFC for HTTP version 2?

It's mostly a session framework on top of SSL but under HTTP.

From http://dev.chromium.org/spdy/spdy-whitepaper

Q: Is SPDY a replacement for HTTP?

A: No. SPDY replaces some parts of HTTP, but mostly augments it. At the highest level of the application layer, the request-response protocol remains the same. SPDY still uses HTTP methods, headers, and other semantics. But SPDY overrides other parts of the protocol, such as connection management and data transfer formats.

Re: A 2x Faster Web

#5

Post by neilc » Thu, Nov 12, 2009, 6:54 PM UTC

I'm impressed that they're able to get such good performance (and latency) while still running the traffic over SSL. For example, average page load time over SSL is 1899 ms ("SPDY basic single-domain / SSL"), compared to 3112 ms for plain HTTP -- they don't show HTTPS, but presumably that would be even slower.

Re: A 2x Faster Web

#6

Post by jeremyw » Thu, Nov 12, 2009, 6:59 PM UTC

One imagines djb envisioning a single roundtrip for encrypted HTTP, built on top of DNSCurve.

You have the public key via DNS, you send an encrypted request and receive a verifiable encrypted response that includes content and begins the multiplexed channel.

Re: A 2x Faster Web

#7

Post by swombat » Thu, Nov 12, 2009, 7:16 PM UTC

Impressive, how Google are taking on challenges that pretty much no other company could possibly address... replacing email... enhancing HTTP, etc...

They're the only company with the means to take on such massive, unprofitable projects, and at the same time enough street cred that everyone won't immediately assume they're trying to make the web proprietary. The fact that they tend to open up these things from the get go helps, too.

Re: A 2x Faster Web

#8

Post by shimon » Thu, Nov 12, 2009, 7:17 PM UTC

Am I missing their explanation of how a SPDY-capable client and server discover and make use of SPDY instead of HTTP?

For this to take hold in the wild, it has to be possible for me to run a combined HTTP+SPDY server, and for a client connecting to it to automatically make use of SPDY if it is capable. This must happen without user intervention (i.e. we don't expect people to type spdy:// instead of http://).

It seems like this should be possible. Perhaps there could be a special server response that instantly "upgrades" a TCP session from HTTP into SPDY. But I'm not seeing anything about that in the docs; is this part of the SPDY plan (yet)?

Re: A 2x Faster Web

#9

Post by sp332 » Thu, Nov 12, 2009, 7:27 PM UTC

nixme wrote: post #3

The whitepaper has more information: http://dev.chromium.org/spdy/spdy-whitepaper Interesting parts: - "...make SSL the underlying transport protocol, for better security and compatibility with existing network infrastructure." Won't this break many caching models? - "...provides an advanced feature, server-initiated streams. Server-initiated streams can be used to deliver content to the client without the client nee…

The future of the internet is ubiquitous encryption. Better to break caching models ASAP so that fixing them can be done incrementally.

Re: A 2x Faster Web

#10

Post by symesc » Thu, Nov 12, 2009, 7:29 PM UTC

swombat wrote: post #7

Impressive, how Google are taking on challenges that pretty much no other company could possibly address... replacing email... enhancing HTTP, etc... They're the only company with the means to take on such massive, unprofitable projects, and at the same time enough street cred that everyone won't immediately assume they're trying to make the web proprietary. The fact that they tend to open up these things from the ge…

Agreed.

I think the important thing to note is that Google is the only large company whose business model depends almost completely on the success of the Internet.

This is why we see them at bat for Net Neutrality as well as efficiencies within communication protocols.

Microsoft, Apple, Oracle, HP, IBM . . . those companies make their livings in other ways.

The only company comparable to Google would be Yahoo in this way. Their inability to keep engineering talent means their contribution to The-Internet-As-Platform is not as significant.