Introduction to Networking for NonStop S-Series Servers

Local Area Network (LAN) Connections
Introduction to Networking for HP NonStop S-Series Servers—520670-005
9-3
Port Access Method (PAM) Programmatic Interfaces
information about the SLSA subsystem, refer to ServerNet LAN Systems Access
(SLSA) Subsystem on page 2-11.
Port Access Method (PAM) Programmatic Interfaces
The PAM subsystem is an independent interface that provides programmatic interfaces
that can be used by applications programmers to support specialized devices or
applications on a LAN. An application can access two different types of port interfaces
by making file-system procedure calls. The port interfaces are as follows:
•
Link Level Control type 1 (LLC1)
•
Ethernet
The LLC1 connectionless service, often described as a datagram service, allows
network entities to exchange data without establishing a connection at the Data-Link
Layer. No call setup or termination procedures are required; however, the upper-layer
software must provide the mechanisms for message routing, sequencing, delivery,
error-detection, and flow control if required by the application.
The PAM subsystem also provides services to the OSI/AS, OSI/TS, SNAX/XF, and
SNAX/APN subsystems. The OSI/AS and OSI/TS subsystems are PAM clients and
use the port interface using file-system calls. The SNAX/XF and SNAX/APN
subsystems are also PAM clients; however, they use a message-system interface
instead of the port interface.