Network Management

Network Management
This section discusses network management, storage and recovery concepts:
• VLAN - A virtual LAN is a local area network with a definition that maps workstations on some other basis than geographic location (for example, by department, type of user, or primary application). The virtual LAN controller can change or add workstations and manage loadbalancing and bandwidth allocation more easily than with a physical picture of the LAN. Network management software keeps track of relating the virtual picture of the local area network with the actual physical picture.
• Fault Tolerance - Fault-tolerance describes a computer system or component designed so that, in the event that a component fails, a backup component or procedure can immediately take its place with no loss of service. Fault tolerance can be provided with software, or embedded in hardware, or provided by some combination. This is an important component of disaster recovery which is being included more and more in operating system software. For example, Windows 2000 includes RAID and tape backup functions although additional hardware is required.
• Network Attached Storage - Network Attached Storage, or NAS, is a data storage mechanism that uses special devices connected directly to the network media. These devices are assigned an IP address and can then be accessed by clients via a server that acts as a gateway to the data, or in some cases allows the device to be accessed directly by the clients without an intermediary. Some of the big advantages of NAS include the expandability; need more storage space, add another NAS device and expand the available storage. NAS also brings an extra level of fault tolerance to the network. In a direct attached storage environment, a server going down means that the data that that server holds is no longer available. With NAS, the data is still available on the network and accessible by clients. Fault tolerant measures such as RAID can be used to make sure that the NAS device does not become a point of failure.