computer networking A computer network is a collection of communicating computers and other devices, such as printers and smart phones. In order to communicate, the computers and devices must be connected by wired media like copper cables, optical fibers, or b ...

, the Transport Layer Interface (TLI) was the networking

API An application programming interface (API) is a connection between computers or between computer programs. It is a type of software interface, offering a service to other pieces of software. A document or standard that describes how to build ...

provided by

AT&T AT&T Inc., an abbreviation for its predecessor's former name, the American Telephone and Telegraph Company, is an American multinational telecommunications holding company headquartered at Whitacre Tower in Downtown Dallas, Texas. It is the w ...

UNIX System V Unix System V (pronounced: "System Five") is one of the first commercial versions of the Unix operating system. It was originally developed by AT&T and first released in 1983. Four major versions of System V were released, numbered 1, 2, 3, an ...

Release 3 (SVR3) in 1987 and continued into Release 4 (SVR4). TLI was the System V counterpart to the

BSD The Berkeley Software Distribution (BSD), also known as Berkeley Unix or BSD Unix, is a discontinued Unix operating system developed and distributed by the Computer Systems Research Group (CSRG) at the University of California, Berkeley, beginni ...

sockets programming interface, which was also provided in

Release 4 (SVR4). TLI was later standardized as XTI, the X/Open Transport Interface.

TLI and Sockets

It was originally expected that the OSI protocols would supersede TCP/IP, thus TLI is designed from an OSI model-oriented viewpoint, corresponding to the OSI

transport layer In computer networking, the transport layer is a conceptual division of methods in the layered architecture of protocols in the network stack in the Internet protocol suite and the OSI model. The protocols of this layer provide end-to-end c ...

. Otherwise, TLI looks similar, API-wise, to sockets. TLI and XTI were widely used (?) and, up to UNIX 98, may have been preferred over the POSIX Sockets API with respect to existing standards. However, it was clear at least since the early 1990s that the Berkeley Socket interface would ultimately prevail. TLI and XTI are still supported in SVR4-derived

operating systems An operating system (OS) is system software that manages computer hardware and software resources, and provides common daemon (computing), services for computer programs. Time-sharing operating systems scheduler (computing), schedule tasks for ...

and operating systems conforming to branded UNIX (UNIX 95, UNIX 98 and UNIX 03 Single UNIX Specifications) such as

Solaris Solaris is the Latin word for sun. It may refer to: Arts and entertainment Literature, television and film * ''Solaris'' (novel), a 1961 science fiction novel by Stanisław Lem ** ''Solaris'' (1968 film), directed by Boris Nirenburg ** ''Sol ...

and

AIX Aix or AIX may refer to: Computing * AIX, a line of IBM computer operating systems *Alternate index, for an IBM Virtual Storage Access Method key-sequenced data set * Athens Internet Exchange, a European Internet exchange point Places Belg ...

(as well as the

classic Mac OS Mac OS (originally System Software; retronym: Classic Mac OS) is the series of operating systems developed for the Mac (computer), Macintosh family of personal computers by Apple Computer, Inc. from 1984 to 2001, starting with System 1 and end ...

, in the form of

Open Transport Open Transport was the name given by Apple Inc. to its implementation of the Unix-originated UNIX System V, System V STREAMS networking stack. Based on code licensed from Mentat's Mentat Portable Streams, Portable Streams product, Open Transport w ...

). Under UNIX 95 (XPG4) and UNIX 98 (XPG5.2), XTI was the preferred and recommended supported API for new transport protocols. As a result of deliberations by the Austin Group with the goal of bringing flavors of UNIX that do not provide

STREAMS A stream is a continuous body of surface water flowing within the bed and banks of a channel. Depending on its location or certain characteristics, a stream may be referred to by a variety of local or regional names. Long, large stream ...

, such as

and

Linux Linux ( ) is a family of open source Unix-like operating systems based on the Linux kernel, an kernel (operating system), operating system kernel first released on September 17, 1991, by Linus Torvalds. Linux is typically package manager, pac ...

, under the Single UNIX Specification, the UNIX 03 Single UNIX Specification both declares

as optional, and declares POSIX Sockets as the preferred API for new transport protocols.

Notes

References

* * * * * * * * * * *{{Cite book , first=Steve , last=Zucker , author2=Kari Karhi , publisher=SunSoft , location=Mountain View, CA , title=System V Application Binary Interface—PowerPc Processor Supplement , year=1995 , orig-year=1993

External links

The Open Group's XTI standard

Example client-server application working on Solaris and Linux
Application programming interfaces

TLI and Sockets

See also

Notes

References

External links