Which option is not a method of network segmentation but protects communication channels from infiltration?

Transmission control serves as a mechanism to ensure reliable communication over a network by managing the flow of data and confirming that packets are received correctly. While it plays a crucial role in the integrity and reliability of data transmission, it does not segment a network into smaller parts. Rather, it focuses on ensuring that data is delivered accurately and effectively between devices. This makes transmission control different from methods such as VLANs, physical segmentation, and access control lists, which are specifically aimed at dividing a network into segments to enhance security, performance, or both.

On the other hand, VLANs create distinct broadcast domains within a single physical network, allowing for logical segmentation. Physical segmentation involves physically separating networks using distinct hardware, such as routers or switches, which enhances security and control. Access control lists limit which users or systems have permission to access certain parts of the network, thus functioning as a method of controlling access but not directly contributing to segmentation. Therefore, while the other options are methods of network segmentation, transmission control is concerned solely with communication reliability and does not segment the network.