TLI is defined by SVID as transport mechanism for networking

interfaces, in preference to sockets, which are biased

toward IP and friends. A disavantage is that a process

cannot use read/write directly, but has to use backends using

stdin and stdout to communicate with the network

connection. TLI is implemented in SVR4 using the STREAMS

interface. It adds no new system calls, just a library,

libnsl_s.a. The major functions are t_open, t_bind,

t_connect, t_listen, t_accept, t_snd, t_rcv, read, write.