福州大学：《计算机网络管理》课程PPT教学课件（英文）Chapter 14 Web-Based Management

14.1 NMS with Web Interface and I Web-Based Management Based on the preceding discussion, we recognize that we need to distinguish between the Web interface and Web management.The Web interface deals with how information is presented to the user. A similar approach exists in an SNMP-based management system.For example,a front-end Web interface is available for OpenView Network Node Manager,which makes it appear as a Web- based system.However,it is still a polling-based network management system that uses SNMP queries.Sometimes,the Web interface to an SNMP-based management system is wrongly referred to as Web-based management

14.1 NMS with Web Interface and Web-Based Management Based on the preceding discussion, we recognize that we need to distinguish between the Web interface and Web management. The Web interface deals with how information is presented to the user. A similar approach exists in an SNMP-based management system. For example, a front-end Web interface is available for OpenView Network Node Manager, which makes it appear as a Web￾based system. However, it is still a polling-based network management system that uses SNMP queries. Sometimes, the Web interface to an SNMP-based management system is wrongly referred to as Web-based management

14.2 Web Interface to SNMP Management Two approaches are available to implement a Web interface on existing SNMP-based management systems.The first and short-term approach is to add a Web interface to an existing management system.The second is to have a Web-based system with embedded Web agents in the network components.The most common implementation is to establish a Web server on an NMS platform with an interface to the NMS,as shown in Figure 14.1.The SNMP NMS implementation is platform and operating system- specific,and the agents in managed objects are SNMP agents.The protocol between the agents and the manager is the SNMP communication protocol, traversing over UDP/IP.There is a management console for the NMS,and the Web server resides on the same platform

14.2 Web Interface to SNMP Management Two approaches are available to implement a Web interface on existing SNMP-based management systems. The first and short-term approach is to add a Web interface to an existing management system. The second is to have a Web-based system with embedded Web agents in the network components. The most common implementation is to establish a Web server on an NMS platform with an interface to the NMS, as shown in Figure 14.1. The SNMP NMS implementation is platform and operating system￾specific, and the agents in managed objects are SNMP agents. The protocol between the agents and the manager is the SNMP communication protocol, traversing over UDP/IP. There is a management console for the NMS, and the Web server resides on the same platform

Desktop PC Web Browser NMS Console Web Server SNMP Manager NMS SNMP Managed Objects SNMP Agent Figure 14.1 An SNMP NMS with a Web Interface

Desktop PC Web Browser Web Server Management Applications SNMP/ Proxy Server Other Managed Objects SNMP/Other Agent Figure 14.2 A Proxy Server with a Web Interface

14.3 Embedded Web-Based Management In embedded WBM,Web servers are embedded in the managed objects.Each managed object is assigned a Web address.The management application receives management information from the agents and displays it by means of a Web browser,as shown in Figure 14,3. Web servers are more intelligent than SNMP agents, which mostly read counters and pass information to the manager or respond to a ping.SNMP agents can send unsolicited basic traps to the manager.However, a Web agent could be sophisticated.For example,it could gather RMON information.Communication between an agent and the manager application is HTTP.For small offices,whose management requirements are minimal,the browser could monitor the Web agents directly,without any management application software.Thus embedded Web agents in network elements greatly simplify network management for network administrators

14.3 Embedded Web-Based Management In embedded WBM, Web servers are embedded in the managed objects. Each managed object is assigned a Web address. The management application receives management information from the agents and displays it by means of a Web browser, as shown in Figure 14,3. Web servers are more intelligent than SNMP agents, which mostly read counters and pass information to the manager or respond to a ping. SNMP agents can send unsolicited basic traps to the manager. However, a Web agent could be sophisticated. For example, it could gather RMON information. Communication between an agent and the manager application is HTTP. For small offices, whose management requirements are minimal, the browser could monitor the Web agents directly, without any management application software. Thus embedded Web agents in network elements greatly simplify network management for network administrators

Workstation/PC Web Browser Management Applications inemenana 900e HTTP 执4园 鱼● Managed Objects Web Server Figure 14.3 An Embedded WBM Configuration

Workstation/PC Web Browser Management Applications Web Agent Non-Web Agent HTTP HTTP 9162006e行0 SNMP 9A5式63t Managed Objects Figure 14.4 The Hewlett-Packard Embedded Agent Configuration

Desktop-Resident Management Application Management Interface API Desktop Management Interface (DMI)Software MIF Database Component Interface API Component Agents Figure 14.5 DMI Infrastructure

Chapter 14 Web-Based Management 14.5 Web-Based Enterprise Management There are significant differences between SNMP and DMI.DMTF tried to make them coexist by developing DMI to the SNMP mapping standard (DMI/SNMP),which did not prove successful.DMTF was then assigned in June 1998 a broader Web-Based Enterprise Management (WBEM)task.The goal of the assignment was to unify (not replace)and extend the existing instrumentation and management standards by using object-oriented constructs and design.Then a common management application residing in a Web client could manage network and system components having different management protocol agents via the Internet

Chapter 14 Web-Based Management 14.5 Web-Based Enterprise Management There are significant differences between SNMP and DMI. DMTF tried to make them coexist by developing DMI to the SNMP mapping standard (DMI/SNMP), which did not prove successful. DMTF was then assigned in June 1998 a broader Web-Based Enterprise Management (WBEM) task. The goal of the assignment was to unify (not replace) and extend the existing instrumentation and management standards by using object-oriented constructs and design. Then a common management application residing in a Web client could manage network and system components having different management protocol agents via the Internet

Chapter 14 Web-Based Management WBEM consists of five components:Web client, Common Information Model Object Manager (CIMOM),CIM schema, specific management protocol providers,and managed objects with protocol-specific agents.The WBEM architecture is shown in Figure 14.8. The Web client is a Web browser with management applications.The browser uses HTML for presenting management data.The applications could invoke a request to any protocol-specific agent in the managed object,as well as process any data coming from any agent.The CIM object manager forms the heart of WBEM architecture.It mediates all messages among Web client,managed objects,and CIM schema.The protocol providers are between CIMOM and the protocol-specific managed networks

Chapter 14 Web-Based Management WBEM consists of five components: Web client, Common Information Model Object Manager (CIMOM), CIM schema, specific management protocol providers, and managed objects with protocol-specific agents. The WBEM architecture is shown in Figure 14.8. The Web client is a Web browser with management applications. The browser uses HTML for presenting management data. The applications could invoke a request to any protocol-specific agent in the managed object, as well as process any data coming from any agent. The CIM object manager forms the heart of WBEM architecture. It mediates all messages among Web client, managed objects, and CIM schema. The protocol providers are between CIMOM and the protocol-specific managed networks