provides end-to-end packet delivery — reliable stream over unreliable network uses datagrams or virtual circuits
Transport service primitives Berkeley sockets (used in TCP):
SOCKET — create new comms endpoint
BIND — associate local address with socket
LISTEN — announce accepting connections
ACCEPT — passively establish incoming conn
CONNECT — actively attempt a conn
SEND — send data over connection
RECEIVE — receive data from connection
CLOSE — release connection