Editing Transport Layer Interface (section)

==TLI and Sockets==
It was originally expected that the [[Open Systems Interconnection|OSI]] protocols would supersede TCP/IP, thus TLI is designed from an [[OSI model|OSI&nbsp;model]]-oriented viewpoint, corresponding to the OSI [[transport layer]].  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<ref name="Xns">{{Cite book
|author=X/Open Group
|title=Networking Services (XNS) Issue 5.2
|edition=5.2
|date=January 2000
|publisher=The Open Group
|location=Berkshire, U.K.
|series=CAE Specification
}}</ref> with respect to existing standards.  However, it was clear at least since the early 1990s that the Berkeley Socket interface would ultimately prevail.<ref>{{cite web |author=Andrew L. Russell |date=30 July 2013 |title=OSI: The Internet That Wasn't |work=IEEE Spectrum |url=https://spectrum.ieee.org/osi-the-internet-that-wasnt |access-date=2021-01-10}}</ref> TLI and XTI are still supported in SVR4-derived [[operating systems]] and operating systems conforming to branded UNIX (UNIX 95, UNIX 98 and UNIX 03 Single UNIX Specifications) such as [[Solaris (operating system)|Solaris]] and [[AIX]] (as well as the [[classic Mac OS]], in the form of [[Open Transport]]).  Under UNIX 95 (XPG4) and UNIX 98 (XPG5.2), XTI was the preferred and recommended supported API for new transport protocols.<ref name="Xns" /><ref>{{Cite book
|author=X/Open Group
|title=Networking Services (XNS) Issue 5
|edition=5th
|date=February 1997
|publisher=The Open Group
|location=Berkshire, U.K.
|series=CAE Specification
|isbn=1-85912-165-9
}}</ref>  As a result of deliberations by the Austin Group with the goal of bringing flavors of UNIX that do not provide [[STREAMS]], such as [[BSD]] and [[Linux]], under the Single UNIX Specification, the UNIX 03 Single UNIX Specification both declares [[STREAMS]] as optional, and declares POSIX Sockets as the preferred API for new transport protocols.