DLPI Programmer's Guide

Chapter 1 45

Introduction to DLPI

DLPI Services

Raw-mode Data Transfer

The raw-mode data transfer service provides the same service as the

connectionless data transfer service. The only difference is that the raw-

mode DLS user builds the complete MAC and LLC headers prior to data

transfer, whereas the connectionless-mode DLS user merely speciﬁes the

peer DLS user and the DLS provider then builds the complete MAC and

LLC headers before transferring the packet.

The DL_HP_RAWDATA_REQ conveys one DLSDU to the DLS provider.

The DL_HP_RAWDATA_IND conveys one DLSDU to the DLS user. The

normal ﬂow of messages is illustrated in Figure 1-29.

Figure 1-29 Message Flow: Raw Data Transfer

Error Reporting Service

The raw-mode error reporting service provides the same services as the

connectionless-mode error reporting services. However, the

DL_ERROR_ACK primitive is used in place of the DL_UDERROR

primitive to report all error conditions in raw-mode.

Figure 1-30 Raw-Mode Error Reporting

XID and TEST Service

The XID and TEST service enables the DLS user to issue an XID or

TEST request to the DLS provider. On receiving a response for the XID

or TEST frame transmitted to the peer DLS provider, the DLS provider

sends up an XIS or TEST conﬁrmation primitive to the DLS user. On

receiving an XID or TEST frame from the peer DLS provider, the local

DL_HP_RAWDATA

request

DL_HP_RAWDATA

indication

DL_ERROR_ACK

indication