Khan Academy The Internet Practice Test

TCP’s main job is to ensure reliable delivery of data between two endpoints. It establishes a connection, slices data into segments, and numbers them so the receiving end can put them back in order. It uses acknowledgments and, if a segment is lost or corrupted, retransmits it, so data arrives intact and in the right sequence. It also manages flow control so the sender doesn’t overwhelm the receiver. Because of these features, TCP is the protocol that guarantees reliable transmission of packets. Encryption (for security), DNS resolution (mapping names to addresses), and routing (deciding paths through the network) are handled by other parts of the network stack.