Protocols are rules that define how messages between computers are sent. They determine how quickly and securely information is transmitted across networks, as well as how to handle errors in transmission. Students model how data is sent using protocols to choose the fastest path and to deal with missing information. Knowledge of the details of how specific protocols work is not expected. The priority at this grade level is understanding the purpose of protocols and how they enable efficient and errorless communication. For example, students could devise a plan for sending data representing a textual message and devise a plan for resending lost information. Alternatively, students could devise a plan for sending data to represent a picture, and devise a plan for interpreting the image when pieces of the data are missing. Additionally, students could model the speed of sending messages by Bluetooth, Wi-Fi, or cellular networks and describe ways errors in data transmission can be detected and dealt with.