The Hardware Side of Networking

The Hardware Side of Networking

A network is two or more computers that have been connected together for the purposes of exchanging data and sharing resources. Networked shared resources range from printers, CD-ROMs, and modems to files and hard disks. Networks vary in size and scope.

Many types of computer networks exist, but you need only be concerned with the following:

l Peer-to-peer network: This type of network includes two or more PCs connected to share data files, a printer, or other resources.

l Local area network (LAN): A small business or corporate department may install a LAN interconnecting from two to hundreds of PCs, using permanently installed cabling or perhaps a wireless technology.

l Wide area networks (WAN): A corporation may maintain a WAN using dial-up, leased, or other dedicated communication means.

Also be familiar with the following network terminology and characteristics:

l Topology: The geometric arrangement of any network is its topology. The most common topologies are the bus, star, and ring topologies.

l Protocol: To operate efficiently, any communications-based system must have an established set of rules--its protocol --to govern its operation. Popular protocols for LANs are Ethernet, token ring, and FDDI.

l Data packets: Data, messages, and tokens that are transmitted on any network must conform to the size and format prescribed under the network's protocol. Data packets also vary between network operating systems (NOS) on the same protocol.

l Architecture: Any network can be classified as either a peer-to-peer or client/server architecture.

When all nodes on a network are equal and resources are shared equally, the network is a true peer-to-peer network. When one computer is designated to host programs or files for the rest of the network, it is a server, and the other nodes are clients.

l Media: Nodes on a network are connected by twisted-pair copper wire, coaxial cable, fiber-optic cable, or wireless radio wave connections.

l Server: A network computer from which workstations (clients) access and share files, printers, communications, and other services. Servers can be dedicated to a single service, such as file servers, print servers, application servers, Web servers, and so on. Servers can also be the software that performs, controls, or coordinates a service or resource.

l Node: Any addressable network point, including workstations, peripherals, or other network devices. The term node is commonly used interchangeably with workstation.

l Workstation: A personal computer that runs application or utility software and uses data stored locally or provided by a network server to which it is connected by a cable or media. Workstations are also known as clients.

The network's domains

A domain has several different uses. The three common uses of domain in networking are the following:

l Windows NT/2000 domain: A group of network servers and devices that appear to end-users as a single network.

l Internet domain: An element of the Domain Name Server (DNS) naming hierarchy.

l NetWare domain: The memory segment within NetWare used to separate NetWare Loadable Modules (NLMs) from the operating system.

Internet domains

The highest level of domains defined by the DNS is standardized to group domain names by the type of organization or geographical location. The top-level Internet domains are

l .com: for companies intending to make a profit (such as hungryminds.com )

l .edu: for schools, colleges, and universities (such as purdue.edu )

l .gov: for the not-secret government agencies (such as whitehouse.gov )

l .int: for international organizations outside of the U.S. (such as europa.eu.int )

l .mil: for the U.S. Armed Forces (such as pentagon.mil )

l .net: for networking services providers (such as innw.net )

l .org: for charitable and other nonprofit organizations (such as redcross.org )

Network domains

Servers and workstations are classified into domains by the role they play on the network. Network domains and their controllers and the names of the resources in a domain are important things to know for the exam:

Domain controller

Remember In the context of a Windows NT Server or Windows 2000 Server network, a domain is a collection of hardware and software resources and the user accounts that have access to them. The resources may include multiple servers, printers, CD-ROM drives, RAID, and other devices attached to the network.

On a domain, one server is designated as the Primary Domain Controller (PDC) and manages user logons and the permissions assigned to the domain resources. One or more of the other servers on the network are designated as a Backup Domain Controller (BDC). The BDC serves as a backup controller to the PDC, but also maintains the user account database for the network. Like the first runner-up in a beauty pageant, a BDC can be promoted to PDC if the PDC is for some reason unable to fulfill its official duties.

Share names

Resources are made available to the domain through share names, which are assigned by the network administrator. To access any resource on a domain, a user needs two things: the appropriate access permissions and the share name of the device. For example, a printer shared over the network may be named GUTENBURG, the PDC named BUSH, and the BDC named CHENEY. These names are then used to access these devices over the network. Share names provide network users with an easily remembered reference to use in lieu of physical hardware addresses. I cover share names more in "Sharing print and file services" later in this chapter.