1. LAN Network Management Technology
Network management technology is the management of the configuration, operation status, and billing of computer networks. It provides means to monitor, coordinate, and test various network resources and network operations, and can also provide functions such as security management and billing.
1.1 Network management technology includes three aspects:
(1) Understand the network: Identify the hardware status of network objects, distinguish the topology of local area networks, determine the interconnection of networks, and determine user load and location.
(2) Network operation: Configuring the network and selecting the network protocol are important components of configuring the network; configuring the network server; and network security control.
(3) Network maintenance: mainly includes fault detection and troubleshooting, discovering faults, tracing faults, troubleshooting, and recording fault solutions; network inspection; network upgrade, mainly including user license upgrades, server operating system upgrades, and server hardware upgrades.
1.2.LAN management tools
NetWare Management Tools: SYS-CON Tools
Windows NT Administrative Tools: Service Manager, Performance Monitor
2. Network management technology function
2.1 4 functions of network management
Configuration management: Automatic acquisition of configuration management. The automatic configuration information in network devices can be roughly divided into three categories according to the acquisition method. The first category is the configuration information defined in the MIB of the network management protocol standard; the second category is the configuration information that is not defined in the network management protocol standard but is important for device operation; the third category is some auxiliary information used for management; automatic backup and related technologies; configuration consistency check; user operation record function.
Performance management: Filter and merge network events, effectively discover and locate network faults, provide troubleshooting suggestions and tools, and form a complete set of fault discovery, alarm, and processing mechanisms.
Fault management: Collect and analyze performance data of network objects, monitor the performance of network objects, and analyze the quality of network lines.
Security management: Combine user authentication, access control, data transmission, storage confidentiality, and integrity mechanisms to ensure the security of the network management system itself. Security management is divided into three parts. The first is the security of the network management itself, and the second is the security of the managed network objects.
2.2 Network Management Protocol
- IAB initially formulated a development strategy for internet management and adopted SGMP as a temporary management solution. Later it evolved into SNMP, the Simple Network Management Protocol.
- SNMP Simple Network Management Protocol provides management services at the third layer of the OSI network layer
Advantages: The management information structure (SMI) and management information base (MIB) related to SNMP are very simple, so they can be implemented quickly and easily; SNMP is based on SGMP, and we have accumulated a lot of operational experience with SGMP.
SNMP is designed based on the principles of simplicity and ease of implementation.
- CMIS/CMIP Public Management Information Service and Public Management Information Protocol: It is a network protocol cluster provided on the OSI application layer. CMIS/CMIP provides the functions required to support a complete network management solution.
CMIS provides the CMIP interface used by applications and also includes two ISO application protocols: contact control service element ACSE and remote operation service element ROSE. ACSE establishes and closes contacts between applications, while ROSE handles request/response interactions between applications.
- CMOT public management information service and protocol is a CMIS service implemented on the TCP/IP protocol, which is a transitional solution. CMOT does not directly use the presentation layer implementation in the reference model, but requires the use of another protocol in the presentation layer, the Lightweight Presentation Protocol (LPP), which provides interfaces for the two most common transport layer protocols TCP and UDP.
- LMMP LAN Personal Management Protocol, a common management information service and protocol CMOL on IEEE802 logical link control LLC, does not rely on any specific network layer protocol for network transmission.
3. Simple Network Management Protocol SNMP
1 SNMP Overview
The design was based on four concepts and goals: keeping the software cost of the management agent as low as possible; maximizing the remote management capabilities to fully utilize Internet resources; the architecture must have room for expansion; and maintaining SNMP independence, without relying on specific computers, gateways, and network transmission protocols.
Four types of management operations are provided: get operations are used to extract specific network management information; get-next operations provide powerful management information extraction capabilities through traversal activities; set operations are used to control management information; trap is used to report important events.
SNMP defines the relationship between management processes and management agents, which is called a community. The software located on network management workstations and network elements that use SNMP to communicate with each other to manage the network are collectively called SNMP application entities.
SNMP application entities operate on management objects in the Internet management information base (MIB). SNMP messages always originate from each application entity, and the message includes the community name of the application entity. This kind of message is called an “identity-marked message”. The community name is used when exchanging management information messages between the management process and the management agent.
The management information message includes: the community name and data.
SNMP implementation method: SNMP uses a tree-like naming method in its MIB to name each managed object instance. Most of the management information in SNMP exists in the form of tables, one table corresponds to one object class, and each element corresponds to an object instance of the class.
- SNMP is an asynchronous request/response protocol, a non-connection-oriented protocol, a symmetric protocol, and has no master-slave relationship. The design of SNMP is based on the connectionless User Datagram Protocol UDP. The interaction process of the four basic protocols is to request the management process to the management agent, and the response is sent by the management agent to the management process. Only Trap is non-responsive and is sent unidirectionally from the management agent to the management process.
The protocol data unit (PDU) between SNMP protocol entities has only two different structures and modes. One PDU format is used in most operations, while the other is used as the trap protocol data unit in Trap operations.
- A trap operation is an operation that captures events and reports them. In fact, almost all network management technology systems and management protocols have this mechanism.
4. Network Management Technology System
- HP – Open View
It cannot handle the failure of other objects caused by the failure of one network object, and cannot understand the relationship between all network objects in the network. It cannot distinguish between service failures and device failures. Performance polling is completely separate from status polling, which results in a network object failing to respond to performance polling but not triggering an alarm.
- IBM-Net View
It cannot merge fault events, and it cannot find the internal relationship of related fault cards. Therefore, a failed device, even an important router, will result in a large number of fault cards and a series of similar alarms. It cannot manage scattered objects while mastering the entire network structure. Performance polling and status polling are also completely separated, which will lead to delays in fault response.
- SUN-SunNet Manager
It was the first important UNIX-based network management system.
- Cabletron SPECTRUM
It is an extensible and intelligent network management technology system that uses an object-oriented approach and client-server architecture. SPECTRUM is built on an artificial intelligence engine, IMT (Inductive Modeling Technology). It is the only system among all four network management software that has the ability to handle network object relevance.
The SPECTRUM server provides two types of polling: automatic polling and manual polling.
SPECTRUM provides a variety of warning methods, including pop-up windows, alarm sounds, etc.
SPECTRUM can automatically discover the topology, but it is relatively slow.