Understanding how different types of digital communication work can help us make design choices, and enable us to write better technical documentation.
The OSI Model is a standard way of conceptualizing the organization of communications systems. It is a good place to start before learning about the specific technologies involved.
A transport protocol defines how packets are sent and received. In the context of networking, there are 2 we care about: TCP and UDP.
TCP powers the internet. Notable features include guaranteeing delivery of packets, guaranteeing the order in which packets are recieved, and congestion management. It requires a connection to be established before data is transmitted. TCP is good for sending messages that you want to be sure are delivered properly, where some latency/delay is acceptable. Read more.
Most communication for the UAS ground station uses TCP.
UDP does not guarantee delivery or order of packets, but there is less overhead and no latency/delay. It is good for streaming real-time data where it is acceptable to lose some information. Read More.
MAVLink, the software that is used to interface with the PixHawk flight controller, can transmit messages using UDP.