Both source and destination processes in TCP are identified by what?

The correct answer is that both source and destination processes in TCP are identified by ports. In the context of the Transmission Control Protocol (TCP), a port number is used to distinguish different processes or services running on the same device. Each application that communicates over the network does so using a unique combination of an IP address and a port number, often referred to as a socket.

When a TCP connection is established, the source process (the application sending the data) specifies a source port, and the destination process (the application receiving the data) specifies a destination port. This architecture allows multiple applications to run on the same server without interfering with each other, and it facilitates proper routing of data packets to the correct application.

The other options do not accurately describe how TCP identifies processes. Protocols refer to the set of rules governing the transmission of data, addressing schemes pertain to how devices are uniquely identified on the network (such as IP addresses), and connection types generally refer to the state of a connection rather than specifying the processes involved. Thus, ports are the specific identifiers that enable the differentiation of processes in the TCP communication model.