Document revision date: 30 March 2001

## OpenVMS System Manager's Manual

Previous | Contents | Index

## Chapter 23
Network Considerations

This chapter discusses the following subjects:

- TCP/IP and DECnet networking software options for OpenVMS systems
- How to decide which networking software options are appropriate for your OpenVMS system
- How to prepare your system to join a network
- Where to obtain detailed information to help you install, configure, and manage the networking software you choose

The material provided in this chapter is intended as an introduction only. For complete planning, installation, configuration, use, and management information about the networking products, refer to the applicable product documentation.

Information Provided in This Chapter

This chapter explains the following concepts:

Concept | Section
--- | ---
Networking software options for OpenVMS systems | Section 23.1
Introduction to Compaq TCP/IP Services for OpenVMS software | Section 23.3
Introduction to DECnet-Plus for OpenVMS software | Section 23.8
Using DECnet over TCP/IP | Section 23.11

This chapter describes the following tasks:

Task | Section
--- | ---
Choosing the networking software appropriate for your system | Section 23.2
Preparing to join a TCP/IP network | Section 23.4
Installing and configuring TCP/IP Services | Section 23.5
Starting and stopping TCP/IP Services | Section 23.6
Preparing to join a DECnet-Plus network | Section 23.9
Installing and configuring DECnet-Plus | Section 23.10
Moving from DECnet Phase IV to DECnet-Plus | Section 23.12
Starting and stopping DECnet-Plus | Section 23.13
Running DECnet applications over an IP network backbone | Section 23.11

## 23.1 OpenVMS Networking Software Options

The ability to connect your OpenVMS system with other systems and networks is a fundamental part of the OpenVMS operating system.

The following networking software options are available for OpenVMS systems:

- Compaq TCP/IP Services for OpenVMS
- TCP/IP implementations for OpenVMS from vendors other than Compaq
- Compaq DECnet-Plus for OpenVMS (Phase V)
- Compaq DECnet for OpenVMS (Phase IV)

You can install and use one of these networking options on an OpenVMS system, or you can install and use combinations of the options to accomplish the following:

- Interoperate with and share resources with other OpenVMS systems
- Interoperate with and share resources with systems running other operating systems, such as UNIX and Windows NT
- Use DECnet protocols and applications in combination with TCP/IP protocols and applications

## 23.2 Choosing Compaq Networking Software

Table 23-1 describes the Compaq layered networking software for OpenVMS systems. The software is available for you to install during the OpenVMS operating system installation or upgrade procedure. Or, you can install the software separately as layered products.

Table 23-1 Choosing Compaq Networking Software for OpenVMS Systems
Product | Description
--- | ---
Compaq TCP/IP Services for OpenVMS | TCP/IP Services is the Compaq implementation of the industry-standard Transmission Control Protocol and Internet Protocol (TCP/IP) suite of protocols and Internet services for OpenVMS VAX and Alpha systems. If your OpenVMS system needs to communicate with heterogeneous networks (such as the Internet, UNIX systems, and Windows NT systems), you should choose Compaq TCP/IP Services for OpenVMS software. With TCP/IP Services, you can connect to remote hosts and access files, exchange messages, develop applications, monitor the network, and perform other important tasks. You can use TCP/IP Services on your system as your only networking software. OpenVMS does not require that you use DECnet software. TCP/IP protocols can coexist with DECnet-Plus protocols. You can install TCP/IP Services to serve as your network backbone and install DECnet-Plus as well, so that you can continue to use DECnet applications and functionality. For information about using DECnet protocols over an IP backbone, see Section 23.11. For an introduction to installing, using, and managing TCP/IP Services software, see Section 23.3.
DECnet-Plus for OpenVMS (Phase V) | DECnet-Plus is the Compaq Phase V implementation of the Digital Network Architecture (DNA). The software provides full backward compatibility with the older DECnet Phase IV product as well as the ability to run DECnet (NSP) and OSI over a DECnet, OSI, or TCP/IP network backbone. For information about using DECnet and OSI protocols over an IP backbone, see Section 23.11. If your OpenVMS system needs to communicate using DECnet (Phase IV and Phase V) or OSI applications and protocols, and if your system needs to coexist with TCP/IP or OSI protocols, or both, you should choose DECnet-Plus software. If you are gradually upgrading your network from DECnet Phase IV, the DECnet-Plus features help you by allowing you to use Phase IV functionality as well as the newer OSI features and advantages. For an introduction to installing, using, and managing DECnet-Plus software, see Section 23.8. Note: Because DECnet-Plus contains both DNA Phase IV and Phase V protocols, you cannot run the separate DECnet Phase IV software product on the same system on which you install DECnet-Plus. For information about upgrading to DECnet-Plus, see the DECnet-Plus Planning Guide.
DECnet for OpenVMS (Phase IV) | DECnet Phase IV is the Compaq Phase IV implementation of the Digital Network Architecture (DNA). The product does not include the OSI protocols and the TCP/IP communications capability of the later DECnet-Plus (Phase V) product. You can run TCP/IP Services software on your system along with DECnet Phase IV, but you cannot run IP as the network backbone. If you intend to use your OpenVMS system to communicate in the traditional OpenVMS environment rather than a heterogeneous environment, you might want to choose DECnet Phase IV, the older DECnet product. This chapter does not contain summary product information about the older DECnet Phase IV product. For information about using DECnet Phase IV, refer to the DECnet for OpenVMS Networking Manual and the DECnet for OpenVMS Network Management Utilities manual (available on the OpenVMS Documentation CD-ROM).

Table 23-2 lists possible networking software combinations for communication between OpenVMS systems.

Table 23-2 Compaq Networking Software Interoperability Options
If System A has... | And System B has... | Systems A and B can communicate using...
--- | --- | ---
TCP/IP Services | TCP/IP Services | TCP/IP applications
DECnet Phase IV | DECnet Phase IV | DECnet applications
DECnet-Plus | DECnet-Plus | DECnet applications OSI applications
DECnet-Plus | DECnet Phase IV | DECnet applications
DECnet-Plus | OSI | OSI applications
TCP/IP Services and DECnet Phase IV | TCP/IP Services | TCP/IP applications
TCP/IP Services and DECnet Phase IV | DECnet Phase IV | DECnet applications
TCP/IP Services and DECnet-Plus | TCP/IP Services | TCP/IP applications
TCP/IP Services and DECnet-Plus | DECnet-Plus | DECnet applications OSI applications
TCP/IP Services and DECnet-Plus | TCP/IP Services and DECnet-Plus | OSI applications DECnet applications DECnet applications using DECnet over TCP/IP OSI applications using OSI over TCP/IP TCP/IP applications
TCP/IP Services and DECnet-Plus | OSI (supporting RFC 1006) and TCP/IP Services | OSI applications OSI over TCP/IP TCP/IP applications
TCP/IP Services and DECnet-Plus | OSI (not supporting RFC 1006) and TCP/IP Services | OSI applications TCP/IP applications

## 23.3 Understanding Compaq TCP/IP Services for OpenVMS

The Compaq TCP/IP Services for OpenVMS product is the OpenVMS implementation of the industry-standard TCP/IP suite of communications protocols as specified in Request for Comments (RFCs) used by the Internet Engineering Task Force (IETF).

With TCP/IP, heterogeneous networks can interconnect, making it possible for users to connect to remote hosts in many ways:

- Network file access. Users can access files on remote hosts.
- Electronic mail. Users can exchange messages between hosts.
- Application development. Application programmers can develop TCP/IP client/server applications for communication between local and remote hosts.
- Download and file transfer. Users can exchange files between hosts.
- User information. Users can access information about other users logged onto the local or remote host.
- Remote management. System managers can monitor the network and applications from remote hosts.
- Remote terminal access. Users can access a remote host as if their terminal is connected directly to that host.
- Remote command execution. Users can issue commands to remote hosts.
- Remote printing. Users can send or receive print jobs to or from remote printers.
- Remote file copy. Users can copy files that reside on remote hosts.
- Remote booting. Servers can provide boot information for remote clients.

Internetworking with TCP/IP hides the hardware details of each individual network and allows computers to communicate independently of their physical network connections. TCP/IP provides both a standard transport mechanism and full-duplex, reliable, stream communication services for software applications.

Compaq TCP/IP Services for OpenVMS software provides interoperability and resource sharing between OpenVMS systems, UNIX systems, and other systems that support the TCP/IP protocol suite and Sun Microsystems' Network File System (NFS). TCP/IP systems and other internet hosts share data and resources by using standard TCP/IP protocols over a number of network hardware configurations: Ethernet, Fiber Distributed Data Interface (FDDI), Token Ring, and asynchronous transfer mode (ATM).

Each end system connected to a TCP/IP network is called a host. Each host has a unique name and address. The local host is the system you are using, and the remote host is the system with which you are communicating. Hosts are connected by lines that carry information between the hosts. The line is the physical path over which data can pass from one host to another. (Examples of lines are telephone lines, fiber-optic cables, and satellites.)

A TCP/IP network is called a packet-switching network. Information is transmitted in small packets of data rather than as a continuous stream from host to host. For example, a file to be transmitted from one host to another is divided into many small packets that are sent across the network one at a time. Each packet contains information about the address of the destination host. At the destination, the packets are reassembled.

The process of directing a data message from a source host to a destination host is called routing. For hosts not directly connected to each other, data can be forwarded from the source to the destination through intervening hosts.

### 23.3.1 Support for OpenVMS Cluster Systems

Compaq TCP/IP Services for OpenVMS supports OpenVMS Cluster systems and the use of cluster aliases. The network sees the cluster as one system with one name, called the internet alias. A remote host can use the cluster alias to address the cluster as one host or use the host name of a cluster member to address a cluster member individually.

### 23.3.2 TCP/IP Services Management Tools and Utilities

Compaq TCP/IP Services for OpenVMS provides a comprehensive, easy-to-use network management tool that includes over 100 OpenVMS DCL-style commands. These commands allow you to locally configure, monitor, and tune TCP/IP Services components by issuing management commands at the `TCPIP>` prompt.

You can also use UNIX management commands to manage some components.

For detailed information about managing TCP/IP Services on your system, refer to the Compaq TCP/IP Services for OpenVMS Management guide.

## 23.4 Preparing to Join a TCP/IP Network

Before you can configure a host to run TCP/IP, you must have a unique IP address and host name. Unlike network hardware addresses, which are hardcoded and fixed, an IP address is assigned by a network administrator. Networks connected to the public Internet must obtain an official, unique network ID from the InterNIC. The IP address has a total of 32 bits (four octets) that identify the network and host. A host name is the name assigned to a computer to facilitate communication.

In addition to providing host and network IDs, the IP address provides information that helps a host determine which packets it should receive and which packets it should ignore. In order for a host to know whether or not another host is on the same or a different subnet, the host compares its own address and the address of the destination computer to a subnet mask. If the network ID of the destination matches the network ID of the source, the packet is delivered to the destination host on the local network. If the network IDs do not match, the packet is forwarded through an IP router to the destination computer.

In addition to an IP address and host name, you must obtain the following information from your network administrator:

- The address for the default gateway, if your systems needs to communicate with TCP/IP hosts not on the local network
- The routing protocol the network uses
- The address of the domain name server (or servers) that will resolve host names into IP addresses
- The network subnet and broadcast masks

You must also decide which end-user services to provide and whether your system is operating as a client, server, or both.

For more information about planning to install and configure Compaq TCP/IP Services for OpenVMS, refer to Digital TCP/IP Services for OpenVMS Concepts and Planning.

## 23.5 Installing and Configuring TCP/IP Services

You can install Compaq TCP/IP Services for OpenVMS software on your system in either of the following ways:

- From the OpenVMS installation procedure menu, as part of the operating system upgrade or installation
- As a layered application using the DCL command PRODUCT INSTALL

Once TCP/IP Services software is installed successfully, you invoke the menu-based configuration procedure, as follows, to configure the software according to the unique characteristics of your system and network:

    $ @SYS$MANAGER:TCPIP$CONFIG

For detailed installation and configuration information, refer to the Compaq TCP/IP Services for OpenVMS Installation and Configuration manual.

## 23.6 Starting and Stopping TCP/IP Services

To start Compaq TCP/IP Services for OpenVMS software on your system after you configure the standard software and optional components, or to stop the software for an orderly shutdown, enter:

    $ @SYS$MANAGER:TCPIP$CONFIG

Then enter the appropriate menu option to start or stop TCP/IP Services.

## 23.7 TCP/IP Services Documentation

Table 23-3 lists the documentation that supports Compaq TCP/IP Services for OpenVMS. For detailed information about how to plan for, install, and use TCP/IP Services, refer to these documents.

Table 23-3 Compaq TCP/IP Services for OpenVMS Documentation
Manual | Contents
--- | ---
Compaq TCP/IP Services for OpenVMS Release Notes | Describes changes to the software including installation, upgrade, and compatibility information. These notes also describe new and existing software problems and restrictions, and software and documentation corrections.
Digital TCP/IP Services for OpenVMS Concepts and Planning | Introduces TCP/IP concepts and components and provides information to help you plan your software configuration.
Compaq TCP/IP Services for OpenVMS Installation and Configuration | Explains how to install and configure the Compaq TCP/IP Services for OpenVMS product on you OpenVMS host.
Digital TCP/IP Services for OpenVMS User's Guide | Describes how to use the applications available with TCP/IP Services such as remote file operations, E-mail, TELNET, TN3270, and network printing. Also explains how to use these services to communicate with systems on private internets or on the worldwide Internet.
Compaq TCP/IP Services for OpenVMS Management | Describes day-to-day management of the Compaq TCP/IP Services for OpenVMS software product.
Command TCP/IP Services for OpenVMS Management Command Reference | Describes the Compaq TCP/IP Services for OpenVMS management commands. A companion guide to the Compaq TCP/IP Services for OpenVMS Management manual.
Compaq TCP/IP Services for OpenVMS Tuning and Troubleshooting | Describes how to troubleshoot Compaq TCP/IP Services for OpenVMS and how to tune the performance of the product.
Compaq TCP/IP Services for OpenVMS Guide to IPv6 | Describes the Compaq TCP/IP Services for OpenVMS IPv6 features and how to install and configure IPv6 on your system.
Compaq TCP/IP Services for OpenVMS Sockets API and System Services Programming | Describes how to use Compaq TCP/IP Services for OpenVMS to develop network applications using Berkeley Sockets Sockets or OpenVMS system services.
Compaq TCP/IP Services for OpenVMS ONC RPC Programming | Provides an overview of high-level programming with open network computing remote calls (ONC RPC), describes how to use the RPCGEN protocol compiler to create applications, and describes the RPC programming interface.
Compaq TCP/IP Services for OpenVMS SNMP Programming and Reference | Describes the Simple Network Management Protocol (SNMP) and the SNMP application programming interface (eSNMP). It describes the subagents provided with TCP/IP Services, utilities provided for managing subagents, and how to build you own subagents.

## 23.8 Understanding DECnet-Plus for OpenVMS Networking Software

DECnet-Plus for OpenVMS provides the means for various Compaq operating systems to communicate with each other and with systems provided by other vendors. The DECnet-Plus network supports remote system communication, resource sharing, and distributed processing. Network users can access resources on any system in the network. Each system participating in the network is known as a network node.

DECnet-Plus is the implementation of the fifth phase of the Digital Netowrk Architecture (DNA). DNA Phase V integrates the OSI protocols with DECnet protocols. In addition, DECnet-Plus includes support for the Internet standard RFC 1006 and the Internet draft RFC 1859, allowing OSI and DECnet applications to run over TCP/IP. Thus, using DECnet-Plus, applications can communicate with peer OSI and DECnet applications on any DECnet Phase IV-based system or OSI-based system, whether from Compaq or from other vendors.

The support of the non-proprietary protocols is the primary difference between DECnet (Phase IV) and DECnet-Plus.

DECnet-Plus provides many features designed to enhance networking capabilities. These features include:

- Global name/directory services that allow large networks to easily store, manage, and access addressing information for (potentially) millions of network objects, such as end systems, users, printers, files, and disks.
- Optional local name/directory services for smaller networks that do not have as critical a need for global directory services.
- Expanded network management capabilities with the Network Control Language (NCL).
- Host-based routing that allows an OpenVMS system to operate as a DECnet-Plus intermediate system in a routing domain.
  This feature is especially useful for those configurations where you need to route from a LAN to a WAN and want to use an existing system to do the routing rather than investing in a dedicated router. Host-based routing is not intended for use in network configurations that have high-throughput requirements.
- Increased addressing capacity with the OSI standard address format, making possible unique addressing for virtually an unlimited number of nodes. Existing Phase IV addresses can continue to be used for systems upgraded to DECnet-Plus. The Phase IV address is automatically converted by the configuration procedure to the OSI address format (as a DECnet Phase IV compatible address).
- Address autoconfiguration that enables an adjacent router to configure the node address for the local node.
- Single configuration for OSI components.
  X.25 (on VAX systems), wide area device drivers (WANDD), File Transfer, Access, and Management (FTAM), and Virtual Terminal (VT) applications are included with DECnet-Plus software. (On Alpha systems, X.25 support is separate from DECnet-Plus software.)

Previous | Next | Contents | Index

| privacy and legal statement |
6017PRO_092.HTML