DLPI Programmer's Guide

Chapter 2 51

DLPI Primitives

Local Management Primitives

This section describes the local management service primitives. These

primitives support the information reporting, Attach and Bind. Once a

stream has been opened by a DLS user, these primitives initialize the

stream, preparing it for use.

PPA Initialization/De-initialization

The PPA associated with each stream must be initialized before the DLS

provider can transfer data over the medium. The initialization and

de-initialization of the PPA is a network management issue, but DLPI

must address the issue because of the impact such actions will have on a

DLS user. More speciﬁcally, DLPI requires the DLS provider to initialize

the PPA associated with a stream at some point before it completes the

processing of the DL_BIND_REQ. Guidelines for initialization and

de-initialization of a PPA by a DLS provider are presented here.

A DLS provider may initialize a PPA using the following methods:

• pre-initialized by some network management mechanism before the

DL_BIND_REQ is received; or

• automatic initialization on receipt of a DL_BIND_REQ or

DL_ATTACH_REQ.

A speciﬁc DLS provider may support either of these methods, or possibly

some combination of the two, but the method implemented has no impact

on the DLS user. From the DLS user’s viewpoint, the PPA is guaranteed

to be initialized on receipt of a DL_BIND_ACK. For automatic

initialization, this implies that the DL_BIND_ACK may not be issued

until the initialization has completed.

If pre-initialization has not been performed and/or automatic

initialization fails, the DLS provider will fail the DL_BIND_REQ. Two

errors, DL_INITFAILED and DL_NOTINIT, may be returned in the

DL_ERROR_ACK response to a DL_BIND_REQ if PPA initialization

fails. DL_INITFAILED is returned when a DLS provider supports

automatic PPA initialization, but the initialization attempt failed.

DL_NOTINIT is returned when the DLS provider requires

pre-initialization, but the PPA is not initialized before the

DL_BIND_REQ is received.