Transport Layer Interface

networking, programming (TLI, or "Transport Level

Interface") A protocol-independent interface for accessing

network facilities, modelled after the ISO transport layer

(level 4), that first appeared in Unix SVR3.

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.

According to the Solaris t_open man page, XTI (X/OPEN

Transport Interface) evolved from TLI, and supports the TLI

API for compatibility, with some variations on semantics.

(1999-06-10)