 queue are statistically correlated due to the collision process on the bus. This property causes also the queue output processes to deviate from a Poisson process, even in the case of Poisson input process and infinite queue length. Thus, in order to analyze the distribution of the latency caused by the passage through the switch fabric, either some approximation is operated to simplify the problem or simu- lation is needed. An effective approximation takes the move from the consideration that the very short length of the inner bus of the switch fabric renders the collision probability very small, especially when bus protocols designed to prevent collisions are used. In this case, the only factor linking the processes happening in the different input queues is the time Tw elapsing between the moment in which a packet is ready to be transmitted in the internal fabric bus and the instant in which it is really transmitted. This time is a random variable depending on the conflict probability. Assuming to ana- lyze a slotted switch fabric, with slot equal to ts, the distribution of Tw is given by (7.26) where p is, as usual, the probability that a ready packet experiences successful transmis- sion in a given slot and it is assumed that no policy is used to favor packets waiting from more time. The latency induced by the switch fabric is then the sum of four terms: 1. The time To needed to ready the packet to enter into the switch system (e.g., apply- ing the internal switch header) 2. The time T1 that the newly arrived packet occupies to wait for the current service 3. The time T2 that the considered packet waits for the service of all the packets in its queue The time T3 elapsing from the moment in which the packet is first in its queue and ready for transmission to its effective transmission that coincides with the service time The time T is a constant, related to the electronic elaboration time, and it can be eliminated from the evaluation for the moment. As far as the times T1 and T2 are concerned, they can be ev