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Data Link Provider Interface (DLPI), Version 2
Copyright © 2000 The Open Group



Data Link Provider Interface


Data Link Service


Data Link Service Access Point


Data Link Service Data Unit


International Organization for Standardization


Open Systems Interconnection


Physical Point of Attachment


Quality of Service


The DLS user in connection mode that processes requests for connections from other DLS users.


The DLS user in connection mode that initiates the establishment of a data link connection.

Communication endpoint

The local communication channel between a DLS user and DLS provider.

Connection establishment

The phase in connection mode that enables two DLS users to create a data link connection between them.

Connectionless mode

A mode of transfer in which data is passed from one user to another in self-contained units with no logical relationship required among the units.

Connection management stream

A special stream that will receive all incoming connect indications destined for DLSAP addresses that are not bound to any other streams associated with a particular PPA.

Connection mode

A circuit-oriented mode of transfer in which data is passed from one user to another over an established connection in a sequenced manner.

Connection release

The phase in connection mode that terminates a previously established data link connection.

Data link service data unit

A grouping of DLS user data whose boundaries are preserved from one end of a data link connection to the other.

Data transfer

The phase in connection and connectionless modes that supports the transfer of data between two DLS users.


A point at which a DLS user attaches itself to a DLS provider, to access data link services.

DLSAP address

An identifier used to differentiate and locate specific DLS user access points to a DLS provider.

DLS provider

The data link layer protocol that provides the services of the Data Link Provider Interface.

DLS user

The user-level application or user-level or kernel-level protocol which accesses the services of the data link layer.

Local management

The phase in connection and connectionless modes in which a DLS user initializes a stream and binds a DLSAP to the stream. Primitives in this phase generate local operations only.


The point at which a system attaches itself to a physical communications medium.

PPA identifier

An identifier of a particular physical medium over which communication transpires.

Quality of service

Characteristics of transmission quality between two DLS users.

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