Alcance
                            ISO 18440:2016 defines a protocol for transfer of SLE PDUs between an SLE user and an SLE provider system in terms of:a)    the procedures used to establish and release associations;b)    the messages exchanged on an established association;c)    the procedures used to monitor the status of data communication connections; andd)    the methods used to ensure that data are converted between different formats and representations on different platforms.It does not specify:a)    individual designs, implementations, or products;b)    the configuration of the data communications infrastructure, including configuration of the TCP and IP protocols;c) the means by which addresses (IP addresses and TCP port numbers) are agreed, assigned and communicated.