SNMP Package Tutorial: Introduction

Introduction

    1. Why JAVA for Network Management?
    2. The Simple Network Management Protocol
    3. JAVA Applications and Applets
    4. System Architecture

This tutorial will help you get started with using the Advent SNMP package from Advent Network Management, Inc. It includes descriptions of a sample Java application and a sample Java applet using the Package to perform SNMP operations. You may also find it useful to consult the Package documentation for more details on the individual classes as you're reading this document.

You can jump straight to the examples if you want to just get on with writing applications.

1.1 Why Java for Network Management?

With all the hype surrounding Java, we don't feel the need to add to it by talking about new paradigms of computing, etc. All the predictions may come to pass, but our view is that Java is still a great cross-platform language for software development. We expect Java to be available for most major operating systems including Windows 3.1. As a language Java provides a simple and elegant means of developing object-oriented code. In addition, it has great support for distributed application development.

Network management application development can benefit from the above as well as allow our users to manage their networks from anywhere. Network managers no longer have to feel constrained be their systems as long as they have access to a notebook computer and a phone (or wireless) line. This is because Java is designed to run inside Web Browsers, which can be found anywhere. For example, the simple MIB browser we've provided works just as well or better from our home PCs on a modem line, as it does in our offices, including the real-time graphs, etc.

1.2 Network Management and the Simple Network Management Protocol (SNMP)

If you're unfamiliar with network management or SNMP, we'd recommend taking a look at the following sites for more information.

SNMP facilitates communication between a managed device (an SNMP agent, e.g. a router), and an SNMP manager or management application (represents a user of network management). Communication is via SNMP protocol data units (PDUs), and essentially four kinds of operations are permitted between managers and agents (managed device).

The primary focus of the Advent SNMP package for development of SNMP managers and management applets and applications in Java. It's also possible to write an agent in Java with this package, and we've provided a simple agent_simulator as an example.

1.3 Java Applications and Applets

There are a lot of excellent sources of information on Java for the uninitiated. Here are a few good places to start.

to name just a few of the many great sites.

Java is a new object-oriented language from Sun Microsystems, that is being developed as a cross-platform development tool for network applications. Each class in Java is compiled into separate class files that can be loaded over the network at run-time. The Java Development Kit (JDK) is the basic toolkit needed to compile and run java programs.

Java applets are java programs that can run in a Java-enabled World-Wide-Web browser like Netscape Navigator These browsers often place restrictions on the capabilities of the applets, sometimes for valid security reasons. For example, currently an applet in Netscape's browser cannot communicate directly with any host on the network, except the web server from which the applet was downloaded. These restrictions may be relaxed soon, using applet signatures to verify trusted sources, or through providing the user some choices, but we're not there yet.

Java applications are Java programs that do not run in the browser environment, and hence do not have any special restrictions over and above the standard OS restrictions.

The Advent SNMP Package helps in the development of network management applications and applets. For applets, special support is provided to get around the security restriction above. Advent provides a Java program for the web server called the SNMP Applet Server (SAS) that allows the applet to send and receive SNMP packets to and from any managed devices accessible from the applet host. You will need to run this program on your web server if you intend to use a browser and load your class files from the network, without disabling security.

1.4 System Architecture

To develop Java applets and applications the Advent SNMP package, you will need the Java Development Kit (JDK) to compile your programs. You can run applications from the command line, and run applets using the appletviewer that comes with the JDK. For applets you can use any Java enabled browser, like Netscape for example.

To run any applets that you develop, you can load all Java class files from your local filesystem, or load them from the network via a Web Server. In the latter case you will need the JDK on your web server. Section 6 describes this in more detail. To summarize, the following configurations are supported.


Advent Network Management, Inc
4 Infield Lane, Aberdeen, NJ 07747
Phone: (800) 487-3309 or (908) 866-8378
Fax: (908) 566-1598
Email: info@adventnet.com