An introduction to SPDY, a next-generation protocol for a faster web.

1. SPDY Up to 11
LINKed Together 2012
Gavin Thirlwall
Support Engineer
COMPUTERLINKS UK
gavin.thirlwall@computerlinks.co.uk

2. Why is it called SPDY?
“We wanted a name that captures speed. SPDY, pronounced
"SPeeDY", captures this and also shows how compression
can help improve speed.”

3. OK, so What is it?
• “An experimental protocol for a faster web”
• Developed primarily by Google
• Improves on problems that make HTTP slow and inefficient
for modern websites
• Sits on top of TCP and SSL
• Requires support from both the client (browser) and server

4. What problems does it solve?
• Websites are now made of hundreds of objects
• Each object has a large header request
• We can only request a small number of objects at a time
• Average web page size is increasing – now around 1.1MB
• Users are as demanding as ever…
• … and they are using mobile devices with high latency
500 millisecond delay caused 100 millisecond delay caused
20% traffic decrease. 1% drop in revenue.

6. What does it do?
• Mandates the use of SSL
Although SSL adds latency in general, SPDY connections should
still be faster.
• Allows multiple simultaneous HTTP requests to share a
single TCP connection
Not pipelining.
Avoids the latency of setting up multiple TCP sessions.
Requests can be prioritised.
• HTTP Header Compression
• Server Initiated Connections
Server push
Server hint (X-Associated-Content)
• Reduces page load time by 30-45% without changing
the page

7. Web
Clients Applications
HTTP
HTTP
Web
Clients Applications
One
SPDY
TCP Connection
SPDY

8. How do I use SPDY?
• Use a SPDY Browser…
• You probably already are and don’t realise it.
• and SPDY Web Server…
• More difficult at the moment…
• Apache (mod_spdy), NginX and others are all working on
mainstream support.
• GMail, Google Ads and Twitter are already using SPDY
when available.

9. I can’t change my web server…
• I’ll lose application support
• It’s disruptive
• I need six months of QA
• I use a lame application like Oracle or SAP

10. Use a SPDY Gateway
• Keep your lame application server
• Use a reverse proxy
• In BIG-IP 11.2 (out a few days ago) but requires a SPDY
licence key
USERS DATACENTER
INTERNET
…
BIG-IP
SDPY SPDY GATEWAY
HTTP
• No doubt other vendors will follow

11. That’s It!
• See http://www.chromium.org/spdy for more information
• These slides will be available via the internal Wiki shortly
• Email me if you want the F5 SPDY Implementation Guide