You can expect the TCP/IP to be installed on all the servers and it does a secured packet delivery. As a result most of the times your packets are safly deliverd. Unlike udp, tcp confirms delivery too. Named pipes are mostly used on the windows system. Since there had been a number of known hacks with IPC, for the safty, most of the Network Admin prefer to use TCP over IPC. Some places where they are paranoid about the security, use TCP with SSL (secured socket layer)

Named Pipes:
An interprocess control (IPC) protocol for exchanging information between two applications, possibly running on different computers in a network. Named Pipes are supported by a number of network operating systems (NOSs), including Netware and LAN Manager.


TCP/IP:
Abbreviation for Transmission Control Protocol/Internet Protocol, the suite of communications protocols used to connect hosts on the Internet. TCP/IP uses several protocols, the two main ones being TCP and IP. TCP/IP is built into the UNIX operating system and is used by the Internet, making it the de facto standard for transmitting data over networks. Even network operating systems that have their own protocols, such as Netware, also support TCP/IP.


Hope this would help you to undestand the concepts.
Sam