Exponential backoff iRule and True-Client-IP HTTP header

If I may elaborate, you can move all of the logic in the CLIENT_ACCEPTED event into the HTTP_REQUEST event, and then you have access to the HTTP headers. The beauty of these OSI-based events is that data collected in lower level events is available in upper level events. You can't see HTTP headers in CLIENT_ACCEPTED, because you're still at layer 4. But you can see IP and port information in HTTP_REQUEST because you're at layer 7 and all of the layer 4 data is accessible.

You also should not be using global static variables to hold state_table and session_id values. Those should just be regular variables.