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BEA SNMP Agent Introduction
This chapter provides an overview of Simple Network Management Protocol (SNMP), the Management Information Base (MIB), SNMP protocol, and the BEA SNMP Agent product in the following sections:
Note: If you are upgrading from the BEA Manager product, see the BEA SNMP Agent Release Notes for BEA Tuxedo and BEA WebLogic Enterprise for changes that have occurred in the transition from the BEA Manager product to the BEA SNMP Agent product.
SNMP is an open network management standard for networks based on the Internet network protocols (TCP/IP). The basic SNMP standard for system management is defined in the Network Working Group (NWG) RFC 1157.
SNMP provides a standard system for classifying system information about hardware, software, and other aspects of a distributed client/server system. SNMP network and systems management is based on the manager/agent model described in the network management standards defined by the International Organization for Standardization (ISO).
In the model, shown in Figure 1-1, a network manager exchanges monitoring and control information about network and system resources with distributed software processes called agents.
Figure 1-1 Manager/Agent Model
Any system or network resource that is manageable through this exchange of information is a managed resource. This could be a software resource, such as a message queue or Tuxedo application, or a hardware resource such as a router or NFS file server.
SNMP enables you to correlate fault and performance data collected by different sources. For example, certain database inserts might fail because the file system on which the database resides has become full. This, in turn, might cause a Tuxedo service to fail.
For a management framework to correlate this failure information with other aspects of system information and thus enable pro-active management of the system, all pieces of management information need to be available from the same management console. To achieve this level of correlation, a standardized method of communicating management information is required.
SNMP provides a unified way of representing information about the manageable features of the heterogeneous components of large distributed systems because it is an open network management standard for networks.
Agents function as "collection devices" that typically gather and send data about the managed resource in response to a request from a manager. In addition, agents often have the ability to issue unsolicited reports to managers when they detect certain predefined thresholds or events on a managed resource. In SNMP terminology, these unsolicited event reports are called trap notifications.
MIB Overview
A manager relies upon the Management Information Base (MIB), a database that contains definitions and information about the properties of managed resources and the services the agents support. When a new agent is added to extend the manager's domain, the manager must be provided with a new MIB component that defines the manageable features of the resources managed through that new agent.
The manageable features of resources, as defined in an SNMP-compliant MIB, are called managed objects (also termed management variables or variables). Examples of managed (or MIB) objects include the state of a Tuxedo domain, the number of users currently logged on to a system, the number of physical network interfaces on a router, a process, a piece of hardware, a system performance attribute. or a global static variable in an application. When the heterogeneous components of an enterprise's distributed systems are defined within a common MIB on the management framework, a unified perspective and single access point is provided for managing system and network resources.
The data types and the representations of resources within a MIB, as well as the structure of a particular MIB, are defined in a standard called the Structure of Management Information (SMI). This standard is described in the NWG RFC 1155.
A formal language, known as the ISO Abstract Syntax Notation One (ASN.1), is used to describe MIB data independently of any encoding technique used. SNMP uses a subset of the ASN.1 language to represent a MIB
Note: If a WLE application is not installed, the WLE specific objects included in the BEA Tuxedo MIB (bea.asn1) do not return values.
Within most management frameworks, you can set up conditions to generate alarms generation based on defined event criteria. The criteria typically consist of changes in the values of certain attributes of the managed resources. These attributes are represented as MIB objects. You can also define the action to be taken when a specified event occurs, such as when a particular threshold is crossed.
The Tuxedo and WLE MIB for SNMP supports a full range of Tuxedo and WLE system and application events. These system and application events are transmitted as enterprise-specific traps. See the BEA SNMP Agent MIB Reference for more information about the Tuxedo MIB for SNMP.
SNMP Protocol
SNMP protocol is based on request/response commands. A management framework sends a GET or GET-NEXT command to request values of MIB variables from an agent, or a SET request to modify the value of a variable. Once the data is collected, management frameworks can present views or graphs of the information or take action in response to the information provided by SNMP agents.
Typically, management frameworks save the collected data to a repository for historical reporting. They also commonly include various tools and utilities to analyze the management data. The management framework enables you to automate responses to event-based operations, change access privileges, update application information, and tune application parameters.
Benefits of Network Management Integration
Because Tuxedo and WLE applications are part of an overall organization or business middleware solution, integrating them with SNMP enables you to effectively manage all your large-scale applications using the SNMP-compliant network management tool of your choice. Since most management frameworks support SNMP, BEA SNMP Agent for Tuxedo and WLE applications can be integrated into virtually every management framework. Examples of such management frameworks include:
With these management frameworks, you can manage and control systems, databases, applications, and user access from a centralized management console. The tools available from the management framework enable you to automate and delegate routine and complex system tasks.
Using SNMP to manage Tuxedo and WLE applications provides the following benefits:
The BEA SNMP Agent
The BEA SNMP Agent for Tuxedo and WLE provides the following components to incorporate Tuxedo and WLE information within an SNMP management framework:
These components are shown in Figure 1-2.
Figure 1-2 BEA SNMP Agent Components
The BEA SNMP Agent provides the SNMP link from Tuxedo and WLE applications to SNMP-compliant network management frameworks (such as HP OpenView) for monitoring, control, and alarm notification, as follows:
SNMP monitoring allows any supported SNMP-capable management station to monitor the state of the Tuxedo or WLE system. Also, appropriate actions can be triggered when a variable crosses a predefined threshold.
Using SNMP SET commands, an SNMP-capable management framework can modify the value of Tuxedo or WLE control and configuration parameters.
The Tuxedo or WLE system generates certain system-wide events in case of exceptions (such as a Tuxedo node going down). These events are trapped and sent as an SNMP trap notification to the management framework.
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Copyright © 2000 BEA Systems, Inc. All rights reserved.
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