Often developers believe that since a communication protocol stack is called a TCP/IP stack, porting it to an embedded target provides the target with all TCP/IP functionalities and performance. This is far from true. A TCP/IP stack requires such resources as sockets and buffers to achieve its goal. These resources, however, consume RAM—a scarce resource on an embedded target. Deprived of sufficient resources, a TCP/IP stack will not work better than a RS-232 connection. By using a Transport Control Protocol (TCP) example, this article demonstrates design rules to be considered when porting a TCP/IP stack to an embedded device.