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Introduction to DLPI
DLPI Services
| Attach Service | |||
| The attach service assigns a physical point of attachment (PPA) to a | |||
| stream. This service is required for style 2 DLS providers to specify the | |||
| physical medium over which communications will occur. The DLS | |||
| provider indicates success with a DL_OK_ACK message and failure with | |||
| a DL_ERROR_ACK message. The normal message sequence is | |||
| illustrated in Figure | |||
Figure | Message Flow: Attaching a Stream to a Physical Line | |||
| DL_ATTACH |
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| request |
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| DL_OK |
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| acknowledge |
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| A PPA may be disassociated with a stream using the | |||
| DL_DETACH_REQ. The normal message sequence is illustrated in | |||
| Figure | |||
Figure | Message Flow: Detaching a Stream to a Physical Line | |||
| DL_DETACH |
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| request |
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| DL_OK |
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| acknowledge |
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Bind Service
The bind service associates a data link service access point (DLSAP) with a stream. The DLSAP is identified by a DLSAP address.
DL_BIND_REQ requests that the DLS provider bind a DLSAP to a stream. It also notifies the DLS provider to make the stream active with respect to the DLSAP for processing connectionless data transfer and connection establishment requests. DL_SUBS_BIND_REQ provides the added capability on binding on multiple DLSAP addresses.
Chapter 1 | 31 |