Introduction to Networking for NonStop S-Series Servers

Introduction to Networking for HP NonStop S-Series Servers—520670-005

2-1

Communications Product Concepts

and Components

As new technologies become available and user requirements become more

sophisticated, HP communications products continue to evolve. Even though HP

communications products vary widely in their functions, some common concepts apply

across the product line.

This section describes the following aspects of HP networking and data

communications:

•

Communications Software Concepts on this page

•

Example Product Structures on page 2-11

•

Communications Hardware Concepts on page 2-19

•

Terminals and Workstations on page 2-33

•

Printer Interfaces, Processes, and Printers on page 2-34

Communications Software Concepts

Certain software concepts are common to all or many HP communications products.

Knowing these concepts will make it easier for you to learn to use the products and

especially to learn about other products after you are familiar with a first one. Also, the

similarities let you develop applications and management procedures that use multiple

products in a uniform way.

Layered Structures and Common Components

To achieve communication with a specific kind of device or network, you will often use

several communications products. These products are related as components in a

layered structure (sometimes called a stack), as shown in Figure 2-1

on page 2-3.

Higher-level components, such as HP NonStop TCP/IP, use the services of lower-level

ones, such as the ServerNet LAN systems access (SLSA) subsystem, to accomplish a

connection. In general, the higher-level components are application-oriented, while the

lower-level ones are network-oriented; the lowest-level components control the

physical communications lines.

Note. In some protocols, terms such as high-level and low-level are narrowly defined. In this

manual, the terms are used in their more general sense, where higher-level means closer to

the user and lower-level means closer to the hardware.