MTU stands for Maximum Transmission Unit, which is a measurement in bytes of the largest data packets that an Internet-connected device can accept. The MTU size is a setting that determines the largest packet size that can be transmitted through a system. The Transmission Control Protocol determines the maximum packet transmission size based on the MTU settings. Changing the MTU setting on a router can optimize internet speeds and connectivity. The optimal MTU value for a home internet router is usually 1500. However, some higher-end routers already use a high MTU value, so its a good idea to check before changing the setting. To determine the optimal MTU size for a system, one can use the ping command in the command prompt to test different packet sizes and find the largest size that does not result in packet fragmentation.