Is there an IRules to control active connections?

rule session_limit {   
      when RULE_INIT {   
         array set ::active_sessions { }   
         set ::total_active_clients 0   
         set ::max_active_clients 20   
      }   
      when HTTP_REQUEST {   
         if { not [info exists client_id] } {   
            if { [HTTP::cookie exists "ClientID"] } {   
               set client_id [HTTP::cookie "ClientID"]   
               set need_cookie 0   
            } else {   
               set client_id [string range [AES::key 128] 8 end]   
               set need_cookie 1   
            }   
            if { not [info exists ::active_sessions($client_id)] } {   
               if { $::total_active_clients >= $::max_active_clients } {   
                  HTTP::redirect "http://mydomain.com/error.page"   
                  return   
               }   
               incr ::total_active_clients   
               set ::active_sessions($client_id) 1   
            } else {   
               incr ::active_sessions($client_id)   
            }   
         }   
      }   
      when HTTP_RESPONSE {   
         if { $need_cookie } {   
            HTTP::cookie insert name "ClientID" value $client_id   
            set need_cookie 0   
         }   
      }   
      when CLIENT_CLOSED {   
         if { [info exists client_id] and [info exists ::active_sessions($client_id)] } {   
            incr ::active_sessions($client_id) -1   
            if { $::active_sessions($client_id) <= 0 } {   
               unset ::active_sessions($client_id)   
               incr ::total_active_clients -1   
            }   
         }   
      }   
   }