iRules – The Power of a Programmable Network

Shouldn’t things be easier?

For nearly 9 years F5 solutions have been deployed at the intersection of IP application and network tiers. We’ve had the job of inspecting traffic and making smarter decisions in the network to improve application reliability, scalability, performance, and security; but sitting at this critical crossroads is not always easy. Time and time again, we hear customers tell us about the challenges in getting applications and networks to coordinate well. The applications often are not designed with the network in mind, and the network group really never knows what to expect when the application is deployed or “thrown over the wall.”

I talk to network administrators every week who say something like: “I have two to three really important applications rolling out next quarter. I just have no idea how they will behave in the wild. But I do know we’ll have to scramble and fix it”. When this occurs, management begins to ask themselves, “Why are we experiencing these outages, poor performance, or delays in the project? Is our network really adaptable enough? Why was the application built this way in the first place?”

The reality is most organizations have hundreds if not thousands of applications. This includes emerging technologies as well as legacy and custom applications. Let’s face it, IT and application teams are not just creating an infrastructure, they are trying to build a strategic advantage. And because the network and business expands over time, it’s nearly impossible for applications to be developed to handle all the challenges of your particular network. The response to date has been to find point network solutions, start coding changes within the application, buy more bandwidth, servers, licenses, or in many cases, engineer workarounds. The cost and complexity for most enterprises has reached a boiling point.

So why did F5 invent iRules, what’s it all about?

BIG-IP version 9 sits at the middle of nearly every transaction that hits the network, encrypted or in the clear, watching the complete traffic flow from the transport to content layer. To us, it makes perfect sense why application switches have found their way into nearly every network diagram.

But over time, as organizations have standardized on our solutions, we’ve witnessed that the only constant with applications and the network is change. Every quarter, many customers ask F5 to help them solve and mask new application problems, or support various protocols or operations that can’t be done elsewhere. They say, “After all, BIG-IP is in the right place and it can see everything, could F5 just help me load balance individual sessions for our critical CORBA application? We’ve got millions riding on it and it is not scaling.” And so we quickly learned, as many of our customers have, to expect the unexpected and that’s why we’ve created iRules.

The vision for iRules is to provide a unified toolkit to “do nearly anything to traffic” – without software upgrades, application changes or new boxes to deploy in the network. Though iRules, organizations have a new level of flexibility and power to inject application logic and unprecedented control into the network.

iRules are based on TCL (Tool Command Language), an industry standard language that has been extended to include specific network and application layer control capabilities. The iRules language is an event-based programming language which provides a specialized set of control commands for managing sessions, content and bi-directional application flows. In addition, every function provided by the BIG-IP system, such as SSL encryption, compression, rewriting, connection management, and other services, can be controlled via the iRules language. This allows organizations to selectively target and dynamically change any feature according to network, traffic, and even device conditions.

Smells like marketing, are iRules for real?

We believe that the intelligence and adaptability of our solutions are paramount. As a result, we’ve devoted a tremendous amount of energy into defining, creating and extending iRules into a powerful solution for network administrators, application developers, and partners alike. We’re eager to show you just how powerful it is. To help you learn, leverage, and share information about iRules, we hope the DevCentral site becomes a valued source for getting the most out of F5 solutions.