10.2. Review of Networking Concepts
Networking in HP-UX is composed of several different layers. Figure 10-1 shows the streams-based networking stack for HP-UX 11.00 and later. For HP-UX 10.20 and earlier, the HP-UX networking stack was a monolithic Berkeley-based Unix stack. Unlike the disk subsystem, which uses mainly read and write system calls, networking can use read and write as well as send(2)/recv(2), sendmsg(2)/recvmsg(2), sendto(2)/recvfrom(2), and t_rcv(3)/t_snd(3) for accessing the network. To create a file descriptor for talking across the network, the socket(2) system call can be invoked for the sockets interface and the t_open(3) call can be used for the XTI interface (X/Open Transport Interface).