The OpenSLP project was started by Caldera in an attempt to provide a clean solid implementation of RFC 2614 "An API for Service Location". This API is based on RFC 2608 "Service Location Protocol, Version 2".
Since its inception, OpenSLP has been compiled and used effectively on many platforms, including: most Linux distributions, Solaris, Windows, HPUX, Mac Classic and OSX, BeOS, FreeBSD, and many others. The primary reason for this prolification is that there is no standardized, secure, bandwidth-efficient, robust, service advertising protocol available.
In the last few years, other advertising protocols have been invented. Some of them have become quite popular. Apple's Bonjour, for instance, is really doing well in the zero-conf world. Directories based on LDAP such as Novell's eDirectory, OpenLDAP, and iPlanet have been configured to provide some service location infrastructure. The fact remains however, that no significant solution has ever been created to solve the problems that SLP was designed to solve.
The current version of OpenSLP supports SLPv2 security features, asynchronous multi-threaded execution, IP version 6 support, and many other features that were missing or not entirely implemented in earlier releases of the project.
– John Calcote, Sr. Software Engineer, Novell, Inc. (email@example.com@.firstname.lastname@example.org@email@example.com)