Real world connection limit setting

It is not a good idea to set connection limit because it never give you desired results. A browser can open multiple connections depending on the version so its difficult to gauge the number of users you are letting in. I had a similar requirement and used an irule with cookies to allow exact number of users but still it gets complex, do you want to let x number of users or X number of transactions? If it goes beyond X do we block them or send them to a holding page?. I was looking to set a threshold of X outstanding transactions but that is difficult since we dont know if a request timed out or just was taking too long. So i will have to reset my table quite so often and decided against it.

So in short if you dont care about users beyond the threshold then connection limit might work otherwise its a challenge.