Networking Fundamentals

Introduction to PC Networking

• A computer network allows users to communicate with other users on the same network by transmitting data on the cables used to connect them.
• A computer network is defined as having two or more devices (such as workstations, printers, or servers) that are linked together for the purpose of sharing information, resources, or both.
• The phrase “information superhighway” describes the benefit of the Internet to business and private communication.
• The Internet breaks down barriers of time and space, enabling the sharing of information around the globe almost instantaneously.

Simplex Transmission

• Simplex transmission is a single one-way baseband transmission.
• It is also called unidirectional because the signal travels in only one direction.
• An example of simplex transmission is the signal sent from the cable TV station to the home television.

Half-Duplex Transmission

• This means that only one side can transmit at a time.
• Two-way radios, such as Citizens Band (CB) and police/emergency communications mobile radios, work with half-duplex transmissions.

Full-Duplex Transmission

• Traffic can travel in both directions at the same time.
• A regular telephone conversation is an example of full-duplex communication. Both parties can talk at the same time, and the person talking on the other end can still be heard by the other party while they are talking.

Peer-to-Peer Networks

• In a peer-to-peer network, the networked computers act as equal partners, or peers, to each other.
• As peers, each computer can take on the client function or the server function alternately.

Client/Server Networks

• In a client/server network arrangement, network services are located in a dedicated computer whose only function is to respond to the requests of clients.
• The server contains the file, print, application, security, and other services in a central computer that is continuously available to respond to client requests.

Local-Area Networks (LANs)

• A local-area network (LAN) can connect many computers in a relatively small geographical area such as a home, an office, or a campus.
• It allows users to access high bandwidth media like the Internet and allows users to share devices such as printers.
• The general shape or layout of a LAN is called its topology.
• WLAN, wireless LAN (WLAN) is a wireless local area network that links two or more computers or devices using spread-spectrum
• metropolitan area network (MAN).

Wide-Area Networks (WANs)

• A WAN, as the name implies, is designed to work over a larger area than a LAN.
• Point-to-point lines connect only two locations, one on each side of the line. Point-to-multipoint lines connect one location on one side of the line to multiple locations on the other side.

Networking Media- Coaxial cable

• Networking media can be defined simply as the means by which signals (data) are sent from one computer to another (either by cable or wireless means).
• Coaxial cable is a copper-cored cable surrounded by a heavy shielding and is used to connect computers in a network.
• There are several types of coaxial cable, including thicknet, thinnet, RG-59 (standard cable for cable TV), and RG-6 (used in video distribution).

Networking Media- Twisted-Pair
                                 

• Twisted-pair is a type of cabling that is used for telephone communications and most modern Ethernet networks.
• A pair of wires forms a circuit that can transmit data. The pairs are twisted to provide protection against crosstalk, the noise generated by adjacent pairs.
• There are two basic types, shielded twisted-pair (STP) and unshielded twisted-pair (UTP).

Networking Media – Optical Fiber

• Fiber-optic cable is a networking medium capable of conducting modulated light transmissions.
• Fiber-optic refers to cabling that has a core of strands of glass or plastic (instead of copper), through which light pulses carry signals.
• Signals that represent data are converted into beams of light.

Common Networking Devices HUB,SWITCH

• A hub is a device that is used to extend an Ethernet wire to allow more devices to communicate with each other.
• Hubs are most commonly used in Ethernet 10BASE-T or 100BASE-T networks, although there are other network architectures that use them.
• A switch is a more sophisticated device than a hub, although the basic function of the switch is deceptively simple.
• Ethernet switches are becoming popular connectivity solutions because they increase network performance.
  

Common Networking Devices ROUTER,SERVER

• Routers are slower than switches, but make “smart” decisions on how to route (or send) packets received on one port to a network on another port.
• Server components are those components that are used exclusively with the network server. End users depend on the server to provide the services required.
• To keep the server running at it is optimal performance, a higher level of preventive maintenance must be maintained.

Ethernet

• The Ethernet architecture is based on the IEEE 802.3 standard. The IEEE 802.3 standard specifies that a network implements the Carrier Sense Multiple Access with Collision Detection (CSMA/CD) access control method.
• Standard transfer rates are 10 Mbps or 100 Mbps, but new standards provide for gigabit Ethernet, which are capable of attaining speeds up to 1 Gbps over fiber-optic cable or other high-speed media.
• Each Ethernet station is given a single 48-bit MAC address, which is used to specify both the destination and the source of each data packet

Token Ring

• The Token Ring standards are defined in IEEE 802.5.
• A Token Ring network uses a token (that is, a special signal) to control access to the cable.
• A token is initially generated when the first computer on the network comes online.
• When a computer wants to transmit, it waits for and then takes control of the token when it comes its way.
• The token can travel in either direction around the ring, but only in one direction at a time.
• Fiber distributed data interface (FDDI)