Transport Layer Interface


Transport Layer Interface

(networking, programming)(TLI, or "Transport LevelInterface") A protocol-independent interface for accessingnetwork facilities, modelled after the ISO transport layer(level 4), that first appeared in Unix SVR3.

TLI is defined by SVID as transport mechanism for networkinginterfaces, in preference to sockets, which are biasedtoward IP and friends. A disavantage is that a processcannot use read/write directly, but has to use backends usingstdin and stdout to communicate with the networkconnection. TLI is implemented in SVR4 using the STREAMSinterface. 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/OPENTransport Interface) evolved from TLI, and supports the TLIAPI for compatibility, with some variations on semantics.