On the loss system, the traffic is carried by network generally lower from real traffic that offered to network by customers. This overload traffic cannot proceed by network and will be loss traffic.
Total this loss traffic is an index from network service quality, is called Grade of Service (GOS), and definition as ratio between loss traffic and offered traffic to network.
Offered traffic itself actually is result from total call average from customers and average per call occupation time. Mathematically can explained with equation:
GOS = (A-Y)/A
Because (A-Y) = R = lost traffic
Grade of service = GOS = R/A
Smaller grade of services value, better services that produced. Example, if recommended that grade of services is 0,002, this mean there is two call from every 1000 call or call from every 500 call that offered customer is missing (cannot proceed). If, in one network condition, total customers is same with total server then GOS is same with zero, because every customers that will build a connection will always got success to occupation the server. Network system itself is non-blocking network.
Blocking probability definition as probability that all server on busy network system (dwelled). When all servers busy, then the system is no more to process incoming traffic. In this situation incoming traffic is believed to experience blocking.
Comprehension of GOS with blocking probability truly almost same, that is to explain about call size that cannot serve by network system. Main different between both is, GOS is a size with point of view from network side or switching system. GOS measured based on observation total call from customers that cannot loaded, whereas blocking probability based on observation busy server (dwelled) on switching system. To distinguish between both clearly, GOS usually named as call congestion (call jam, because showing part from call that rejected or unloaded) or probability loss, whereas blocking probability as time congestion (time jam, because showing part from time which all server or busy line).
