TCP/IP Configuration and Management Manual

TCP/IP Configuration and Management Manual—427132-004

B-1

NonStop TCP/IP Processes and

Protocols

This appendix provides additional information about the NonStop implementation of

Transmission Control Protocol/ Internet Protocol. It also includes information on the

services provided by the NonStop TCP/IP environment not documented in Section 1,

Configuration Quick Start and Section 3, Configuring the NonStop TCP/IP Subsystem.

TCP is a set of rules for controlling data transmission; IP is a set of rules for passing

data in an internetworked environment. The TCP/IP protocols originated from research

funded by the Defense Department in the late 1960s in interconnecting networks that

used different hardware. The result was the DARPA (Defense Advanced Research

Projects Agency) Internet, now commonly known as the Internet.

Internet Concepts and Services

The basic concept of internetworking is that cooperating networks use common

protocols to make the entire structure appear as a collection of networks to any device

that has access to it. The Internet continues to grow exponentially in the United States

and abroad.

The Internet provides a number of different services using a variety of protocols, in

addition to the TCP protocol. The services and protocols available in the NonStop

implementation of TCP/IP are described in the following paragraphs.

Addressing

Every transport endpoint, or socket, can be addressed by a combination that includes

an Internet address (IP address) and a port number. This section describes Internet

addresses and port numbers, both of which are used in configuration and

programming.

Internet Addresses

A host can have more than one Internet address because it can be connected to more

than one network. Each physical device, or interface, that adds the host to a new

logical network has its own Internet address.

A host has only one Internet address on each network to which it is attached. However,

because of the multiprocessing nature of the NonStop system and the fact that more

than one NonStop TCP/IP process can exist on a system, a NonStop system can

appear to the outside world as more than one logical host on a network. When a

Note. This appendix is not intended to replace the reference books listed in About This

Manual.