Radius and HTTP Header insertion

where can I find a doc on iRules API?That's a question we keep asking ourselves. Stay tuned to DevCentral and hopefully you'll get an answer. For now, there's DevCentral and on AskF5 there's a reference manual.

 

there is a way to share variables among different BIGIPs?No. You would need to do something very elaborate like make the requests go through both BIG-IP's or use some of the retry logic we added in 9.2 to sync the request between both BIG-IP's.

 

is it possible for me to set some user-configuration variables?What we call Data Groups or Classes are the only option for this at this time.

 

is it possible to send back Radius replies or will I need a backend server to handle Radius?You probably will want a backend server unless your Tcl programming skills are great. It is possible to craft a response, but it would require building binary data in Tcl.

 

How much is BIGIP scalable?That's a very difficult question to answer on-spec. There are many variables that influence the performance of the BIG-IP. Yes, it is very scalable, but exactly how much it can handle is going to depend on a number of factors, even including the rule you mention developing above. Your sales engineers should be able to give you similar performance data that would allow you to extrapolate a general idea. Then when you have everything in place and can measure actual data, you should be able to further extrapolate how scalable the BIG-IP will be in your scenario.