Accounting Management

The goal of accounting management is to measure network utilization parameters so that individual or group uses on the network can be regulated appropriately. Such regulation minimizes network problems (because network resources can be apportioned based on resource capacities) and maximizes the fairness of network access across all users.

In performance management, the first step toward appropriate accounting management is to measure utilization of all important network resources. Analysis of the results provides insight into current usage patterns and usage quotas can be set at this point. Some correction, of course, will be required to reach optimal access practices. from this point, ongoing measurement of resource use can yield billing information as well as information used to assess continued fair and optimal resource utilization.

Security Management

The goal of security management is to control access to network resources according to local guidelines so that the network cannot be sabotaged (intentionally or unintentionally) and sensitive information cannot be accessed by those without appropriate authorization. A security management subsystem, for example, can monitor users logging on to a network resource and can refuse access to those who enter inappropriate access codes.

Security management subsystems work by partitioning network resources into authorized and unauthorized areas. For some users, access to any network resource is inappropriate, mostly because such users are usually company outsiders. For other (internal) network users, access to information originating from a particular department is inappropriate. Access to Human Resource files, for example, is inappropriate for most users outside the Human Resources department.

Security management subsystems perform several functions. They identify sensitive network resources (including systems, files, and other entities) and determine mappings between sensitive network resources and user sets. They also monitor access points to sensitive network resources and log appropriate access to sensitive network resources.

• Authentication: Authentication is the process of identifying users, including login and password dialog, challenge and response and messaging support. Authentication is the way a user is identified prior to being allowed access to the router or switch. There is a fundamental relationship between authentication and authorization. The more authorization privileges a user receives, the stronger the authentication should be.

• Authorization: Authorization provides remote access control, including one-time authorization and authorization for each service that is requested by the user. On a Cisco router, the authorization level range for users is 0 to 15 with 0 being the lowest level and 15 the highest.

• Accounting: Accounting allows for the collecting and sending of security information used for billing, auditing, and reporting, such as user identities, start and stop times and executed commands. Accounting enables network managers to track the services that users are accessing as well as the amount of network resources they are consuming.

Performance Management

The goal of performance management is to measure and make available various aspects of network performance so that internetwork performance can be maintained at an acceptable level. Example of performance variables that might be provided include network throughput, user response times and line utilization.

Performance management involves three main steps. First, performance data is gathered on variables of interest to network administrators. Second, the data is analyzed to determine normal (baseline) levels. Finally, appropriate performance thresholds are determined for each important variable so that exceeding these thresholds indicates a network problem worthy of attention.

Management entities continually monitor performance variables. When a performance threshold is exceeded, an alert is generated and sent to the network management system.

Each of the steps just described is part of the process to set up a reactive system. When performance becomes unacceptable because of an exceeded user-defined threshold, the system reacts by sending a message. Performance management also permits proactive methods: For example, network simulation can be used to project how network growth will affect performance metrics. Such simulation can alert administrators to impending problems so that counteractive measures can be taken.

Fault Detection and Notification

The purpose of fault management is to detect, isolate, notify and correct faults encountered in the network. Network devices are capable of alerting management stations when a fault occurs on the systems. An effective fault management system consists of several subsystems. Fault detection is accomplished when the devices send SNMP trap messages, SNMP polling, remote monitoring (RMON) thresholds and syslog messages. A management system alerts the end user when a fault is reported and corrective actions can be taken.

Fault detection and monitoring of network elements can be expanded from the device level to the protocol and interface levels. For a network environment , fault monitoring can include Virtual Local Area Network (VLAN), asynchronous transfer mode (ATM), fault indications on physical interfaces and so forth.

Troubleshooting Infrastructure

Trivial File Transfer Protocol (TFTP) and system log (syslog) servers are crucial components of a troubleshooting infrastructure in network operations. The TFTP server is used primarily for storing configuration files and software images for network devices. Routers and switches are capable of sending system log messages to a syslog server. The messages facilitate the troubleshooting function when problems are encountered.

Network Management Platforms

A network management platform deployed in the enterprise manages an infrastructure that consists of multivendor network elements. The platform receives and processes events from network elements in the network. Events from servers and other critical resources can also be forwarded to a management platform. The following commonly available functions are included in a standard management platform:

• Network discovery


• Topology mapping of network elements


• Event handler


• Performance data collector and grapher


• Management data browser.

Network management platforms can be viewed as the main console for network operations in detecting faults in the infrastructure. The ability to detect problems quickly in any network is critical. Network operations personnel can rely on a graphical network map to display the operational states of critical network elements such as routers and switches.

Network management platforms such HP OpenView, Computer Associates Unicenter and SUN Solstice can perform a discovery of network devices. Each network device is represented by a graphical element on the management platform's console. Different colors on the graphical elements represent the current operational status of network devices. Network devices can be configured to send notifications, called SNMP traps, to network management platforms. Upon receiving the notifications, the graphical element representing the network device changes to a different color depending on the severity of the notification received. The notification, usually called an event, is placed in a log file.

A number of network management platforms are capable of managing multiple geographically distributed sites. This is accomplished by exchanging management data between management consoles at remote sites with a management station at the main site. The main advantage of a distributed architecture is that it reduces management traffic, thus, providing a more effective usage of bandwidth. A distributed architecture also allows personnel to locally manage their networks from remote sites with systems.

A recent enhancement to management platforms is the ability to remotely management network elements using a web interface. This enhancement eliminates the need for special client software on individual user stations to access a management platform.

A typical enterprise is comprised of different network elements. However, each device normally requires vendor-specific element management systems in order to effectively manage the network elements. Therefore, duplicate management stations may be polling network elements for the same information. The data collected by different systems is stored in separate databases, creating administration overhead for users. This limitation has prompted networking and software vendors to adopt standards such as Common Object Request Broker Architecture (CORBA) and Computer-Integrated Manufacturing (CIM) to facilitate the exchange of management data between management platforms and element management systems. With vendors adopting standards in management system development, users can expect interoperability and cost savings in deploying and managing the infrastructure.

Fault Management

The goal of fault management is to detect, log, notify users of and (to the extent possible) automatically fix network problems to keep the network running effectively. Because faults can cause downtime or unacceptable network degradation, fault management is perhaps the most widely implemented of the ISO network management elements.

Fault management involves first determining symptoms and isolating the problem. Then the problem is fixed and the solution is tested on all-important subsystems. Finally, the detection and resolution of the problem is recorded.

Configuration Management

The goal of configuration management is to monitor network and system configuration information so that the effects on network operation of various versions of hardware and software elements can be tracked and managed.

Each network device has a variety of version information associated with it. An engineering workstation, for example, may be configured as follows:

• Operating system, Version 3.2
• Ethernet interface, Version 5.4
• TCP/IP software, Version 2.0
• NetWare software, Version 4.1
• NFS software, Version 5.1
• Serial communication controller, Version 1.1
• X.25 software, Version 1.0
• SNMP software, Version 3.1

Configuration management subsystems store this information in a database for easy access. When a problem occurs, this database can be searched for clues that may help solve the problem.

Internet and IEEE Network Management Standards

The Internet is a computer network made up to thousands of networks worldwide. All computers on the Internet communicate with one another using the Transmission Control Protocol/Internet Protocol suite, abbreviated to TCP/IP. Computers on the Internet use a client/server architecture. This means that the remote server machine provides files and services to the user's local client machine. Software can be installed on a client computer to take advantage of the latest access technology.

The Internet consists primarily of variety of access protocols. Many of these protocols feature programs that allow users to search for and retrieve material made available by the protocol. An Internet user has access to a wide variety of services: electronic mail, file transfer, vast information resources, interest group membership, interactive collaboration, multimedia displays, real-time broadcasting, shopping opportunities, breaking news and much more.

The World Wide Web (abbreviated as the Web or WWW) is a system of Internet servers that supports hypertext to access several Internet protocols on a single interface Almost every protocol type available on the Internet is accessible on the Web. This include e-mail, FTP, Telnet, and Usenet News. In addition to these, the World Wide Web has its own protocol: HyperText Transfer Protocol, or HTTP.

The World Wide Web provides a single interface for accessing all these protocols. This creates a convenient and user-friendly environment. It is no longer necessary to be conversant in these protocols within separate, command-level environments. The Web gathers together thse protocols into a single system. Because of this feature, and because of the Web's ability to work with multimedia and advanced programming languages, the World Wide Web is the fastest-growing component of the Internet.

IEEE has developed a set of network standards. They include:

IEEE 802.1 - Specifies Network Management Standards.

IEEE 802.2 - Specifies the General standard for the OSI Reference Model data link layer.

IEEE 802.3 - Defines the Media Access Control layer for bus networks that use CSMA/CD.

IEEE 802.4 - Defines the Media Access Control layer for bus networks that use a token-passing mechanism.

IEEE 802.5 - Defines the MAC layer for token Ringh Network.

IEEE 802.6 - Defines MAN's (Metropolitan Area Network) Standard.

IEEE 802.7 - Broadband Technical advisory group.

IEEE 802.8 - Fibre Optic Technical advisory group.

IEEE 802.9 - ISDN (Integrated Services Digital Network).

IEEE 802.10 - Specifies Network Security Standards.

IEEE 802.11 - Specifies Wireless Network Standards.

IEEE 802.12 - Specifies 100 VG Any LAN Standards.

IEEE 802.14 - Specifies Cable Modem Standards.