Which of the following is NOT a factor affecting throughput?

Throughput refers to the rate at which data is successfully transmitted over a network. It is influenced by various factors, but the physical length of the cables typically does not directly affect throughput in the context of modern Ethernet networks, particularly with gigabit speeds or higher. Once within the acceptable length standards (like 100 meters for twisted pair cables), the throughput remains relatively stable regardless of the exact length, given that the network equipment and connections are functioning properly.

On the other hand, the other options can significantly impact throughput. The number of servers on the network can affect the overall capacity and load, which grows as more servers contend for the same network resources. The sophistication of the encapsulation method can introduce overhead or processing delays, influencing how efficiently data is transmitted. Finally, the reliability of gigabit Ethernet infrastructure is crucial, as any faults or inefficiencies in the network can lead to packet loss, retransmissions, and thus reduce the effective throughput.