Although not a protocol, the Java Management API (JMAPI) includes a mapping to SNMP, enabling SNMP-enabled devices to be managed by JMAPI-compliant applications. JMAPI itself is only a framework for management systems. The protocol or standard supported can actually be anything, even RMON, as long as JMAPI includes the appropriate mappings. Sun has indicated that future mappings could include Common Object Request Broker Architecture (CORBA) and Common Management Information Protocol (CMIP).
One vendor offering an implementation of Java classes for SNMP Version 1 is Advent Network Management, Inc. The company's Advent Java SNMP Package helps programmers develop SNMP applets and applications. With the package, developers can focus on using the Web and Java with the Advent Web NMS framework, and produce the best applications and solutions, instead of dealing with multiple proprietary platform vendor APIs and multiple operating system versions.
The Advent Java SNMP Package is a group of Java class files that provide Java programmers a simple API for developing network management applets and applications that use SNMP version 1. Many different architectures are supported, such that SNMP can be used in the Web browser, on the server, or even on managed elements that have a Java Virtual Machine. Applets developed using this package can be loaded from the network or from local disks and run in any Java-enabled browser.
Java applets that are loaded from the network are usually restricted by browsers from connecting to any system other than the applet host. The Advent Java SNMP Package provides special support for applets loaded remotely via the network that run in browsers that have socket and file access restrictions. Via a Java program called the SNMP Applet Server (SAS) on the applet host (Web Server), applets can communicate with SNMP managed devices, and save and retrieve files on the applet host.
Developers can also use the Advent NetMonitor SNMP Applet Builder, which uses the SNMP Package libraries to communicate with SNMP agents. Advent NetMonitor lets developers visually build these applets without writing code. They can then use Java to add their own event handling code and components.
The company also offers a Management Information Base (MIB) Browser Applet (Figure 1). MIB Browsers allow the user to view and operate on data available through an SNMP agent on a managed device, such as a router. To get a better view of the data available on the SNMP agent, a MIB file is usually provided with the managed device. This MIB file contains a description of the object hierarchy on the managed device, as well as the syntax and access privileges for each variable in the MIB.
Figure 1: Shown here is the primary window of the MIB browser applet. (Although the screen is taken from Windows 95, it looks similar in Netscape and on other Java-enabled browsers.) The applet includes fields for community, SNMP agent name or address (Host), value used for a set request, the current Node OID that is being operated upon, a chooser for the current MIB module, a list of children of the current node, and a text area to view query results. The operations allowed with the MIB browser are available through the series of buttons at the bottom of the applet's main window.
The Advent MIB Browser applet provides the capability to load and view multiple MIB modules, and traverse the MIB tree to look at the definitions for each node in the MIB tree. It allows the use of SNMP's get, getnext, and set requests to a particular variable in the MIB of an SNMP managed device. It also enables multiple real-time graphs of data on the managed device to be viewed as it changes over time. It also allows the user to view SNMP tables.
The major NMS platform providers are planning to support Java. IBM subsidiary, Tivoli Systems, for example, plans to evolve its TME 10 framework into a Java-based architecture by mid-1998. The architecture will support JMAPI for enabling Java management applications to take advantage of the platform's back-end functions, such as event and alarm correlation and data management. Computer Associates plans to add the ability to control its Unicenter TNG management functions from a Web browser as well as the ability for Java applications to invoke its functions. Unicenter TNG is the company's object-oriented enterprise management framework.
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