Ccna4 M6 Network Management

CCNA – Semester4

Module 6 Network Management

Objectives

• Differences between a NOS and a traditional OS • Identify network management tools • Describe SNMP and CMIP

Workstations and Servers

Workstations • A workstation uses special softwares to perform the following tasks: – Intercepts user data and application commands – Decides if the command is for the local operating system or for the NOS. – Directs the command to the local operating system or to the network interface card (NIC) for processing and transmission onto the network – Delivers transmissions from the network to the application running on the workstation

Server • Server systems must be equipped to support multiple concurrent users and multiple tasks as clients make demands on the server for remote resources. • Servers usually have high-capacity, high-speed disk drives, large amounts of RAM, high-speed NICs, and in some cases, multiple CPUs.

Introduction to NOS • A computer OS is the software foundation on which computer applications and services run on a workstation. • A NOS enables communication between multiple devices and the sharing of resources across a network.

Windows NT • NT 4 was designed to provide an environment for mission critical business that would be more stable than the Microsoft consumer operating systems. • Program failures are isolated and do not require a system restart. • Windows provide preemptive multitasking, file level security, file-by-file compression

Windows 2000 Professional • Windows 2000 Professional is not designed to be a full NOS. • The primary purpose is to be part of a domain as a client-side operating system. • It can be a file server, a print server, an FTP server, and a web server, but will only support up to ten simultaneous connections.

Windows 2000 Server • The Active Directory Services feature serves as the centralized point of management of users, groups, security services, and network resources. • It includes the multipurpose capabilities required for workgroups and branch offices as well as for departmental deployments of file and print servers, application servers, web servers, and communication servers. • Windows 2000 Advanced Server provides the additional hardware and software support needed for enterprise and extremely large networks.

Windows .NET Server • Windows .NET Server is built on the Windows 2000 Server kernel, but tailored to provide a secure and reliable system to run enterpriselevel web and FTP sites in order to compete with the Linux and UNIX server operating systems.

Origins of UNIX • UNIX was designed to support multiple users, multitasking and marketed for network servers only. • UNIX, in its various forms, continues to advance its position as the reliable, secure OS of choice for missioncritical applications that are crucial to the operation of a business or other organization. • UNIX is also tightly integrated with TCP/IP.

Origins of Linux • Linux was UNIX-like in its operation but used software code that was open and completely free of charge to all users. • Linux is one of the most powerful and reliable operating systems in the world today. • Application support must be considered when Linux is implemented on a desktop system.

Apple • Apple Macintosh computers were designed for easy networking in a peer-to-peer, workgroup situation. • Network interfaces are included as part of the hardware and networking components are built into the Macintosh operating system. • The Macintosh, or Mac, is popular in many educational institutions and corporate graphics departments.

MAC OSX • Mac OS X support for protected memory, preemptive multitasking, advanced memory management, and symmetric multiprocessing. It allows AppleTalk and Windows connectivity.

Concept of service on servers • Remote management is a powerful service that allows administrators to configure networked systems that are miles apart. • Network processes are referred to as services in Windows 2000 and daemons in UNIX and Linux.

Network Management

Network management requirements •

The network administrator must actively manage the network, diagnose problems, prevent situations from occurring, and provide the best performance of the network for the users.

Network management model

SNMP and CMIP standards

SNMP protocols • SNMP was adopted as the standard for TCP/IP internets in 1989 • SNMPv2c provides support for centralized and distributed network management strategies, improves the SMI, protocol operations, management architecture, and security. • SNMPv3 provides secure access to MIBs by authenticating and encrypting packets over the network.

Organizational model for SNMP •

The organizational model for SNMP based network management includes four elements: – – – –

Management station Management agent Management information base Network management protocol

Network management station • Usually a standalone workstation, but it may be implemented over several systems. • It includes a collection of software called the network management application (NMA). • SNMP uses User Datagram Protocol (UDP) and communicates over ports 161 and 162. It is based on an exchange of messages. There are three common message types: – Get: Enables the management station to retrieve the value of MIB objects from the agent. – Set: Enables the management station to set the value of MIB objects at the agent. – Trap: Enables the agent to notify the management station of significant events.

Management information base • MIB is used to store the structured information representing network elements and their attributes. • The structure itself is defined in a standard called the structure of management information (SMI) • SMI defines the data types that can be used to store an object, how those objects are named, and how they are encoded for transmission over a network.

Management agents • Are key network platforms and devices, other hosts, routers, bridges and hubs, equipped with SNMP so that they can be managed. • Provide management information to the NMS. All the management information of a particular agent is stored in the MIB on that agent. • An agent might keep track of the following: – – – –

Number and state of its virtual circuits Number of certain kinds of error messages received Number of bytes and packets in and out of the device Maximum output queue length, for routers and other internetworking devices – Broadcast messages sent and received – Network interfaces going down and coming up

RMON • Network management applications often offload some network management functionality to a remote monitor (RMON) probe. • The RMON probe gathers management information locally, and then the network manager periodically retrieves a summary of this data. • RMON gather statistics by analyzing every frame on a segment.

Components of organization model

Network management applications • The network management applications rely on the host operating system, and on the communication architecture. • Includes a GUI interface to allow the network administrator to monitor and manage the network • Examples of network management applications are Ciscoworks2000, HP Openview, and SNMPv2c.

Understanding the protocol

Understanding the community strings

SNMPv2c message format

SNMPv3 message format

Configuring SNMP • More than one read-only string is supported. • The default on most systems for this community string is public. It is not advisable to use the default value in an enterprise network. • To set the read-only community string used by the agent, use the following command: Router(config)#snmp-server community string ro – String – Community string that acts like a password and permits access to the SNMP protocol – ro – (Optional) Specifies read-only access. Authorized management stations are only able to retrieve MIB objects.

Configuring SNMP • More than one read-write string is supported. • All SNMP objects are available for write access. • The default on most systems for this community string is private. It is not advisable to use this value in an enterprise network. • To set the read-write community string used by the agent, use the following command: Router(config)#snmp-server community string rw – rw – (Optional) Specifies read-write access. Authorized management stations are able to both retrieve and modify MIB objects

Configuring SNMP • There are several strings that can be used to specify location of the managed device and the main system contact for the device. Router(config)#snmp-server location text Router(config)#snmp-server contact text

Cisco syslog • The Cisco syslog logging utility is based on the UNIX syslog utility. • System events are usually logged to the system console unless disabled. • The syslog utility is a mechanism for applications, processes, and the operating system of Cisco devices to report activity and error conditions.

Syslog facility

Configuring syslog • To enable logging to all supported destinations: Router(config)#logging on

• To send log messages to a syslog server host, such as CiscoWorks2000: Router(config)#logging hostname | ip address

• To set logging severity level to level 6, informational: Router(config)#logging trap informational

• To include timestamp with syslog message: Router(config)#service timestamps log datetime

Summary • The functions of a workstation and a server • Development of Networking Operating Systems (NOS) • An overview of the various Windows platforms and other OSes • Reasons for network management • The layers of OSI and network management model • The role that SNMP and CMIP play in network monitoring

CCNA4 – Module6