NETWORKING...

The process of linking 2/3 computing devices together for the purpose of sharing data. 

COMPUTER NETWORKING

• Connecting computer with other computer/devices to enable them to communicate to each other or to share the data.

1.  LAN (Local Area Network)
2. MAN (Metropolitan Area Network) 
3.  WAN (Wide Area Network)
4. PAN (Personal Area Network)

NETWORK COMPONENTS

•   Terminals, Workstations, Computers, and other devices (end nodes)

           -normally refers to data sources and destinations.

           -ex: personal computer, terminals, workstations, automatic teller machines

• Transmission Media

           - for transmitting data and control signals

           - 2 types :

                  *guided (through cable): fibre optic, wire, co-axial

                  *unguided (through vacuum): AM & FM radio, tv broadcasting,                     satellite communication, microwave radio, infrared signals.

• Network electronics

          -devices that controls data transmission from sources to destinations,

          -it also act as interface between different transmission media or                    communication protocol

          -intermediate devices for routing data from source to destination

          -ex: bridges, routers, multiplexers, gateways, hubs

• Software

          -a network operating system (NOS)

          -at the nodes : involve techniques and protocols

          -control data transmission,a network & its message, traffic & queues,

          -control access by multiple users to network resources such as files

          -provides for certain administrative function, including security

• Network Architecture Standards

          -Standards to enable devices made by different companies to                          work/communicate with each other

          -Blueprint of standards for a network consisting of items such as choice of media, media interfaces, encoding methods, transmission protocols, routing protocols, etc.

           -Needed to ensure interoperability between various devices and equipment made by different vendors.

WHAT???

AM 

• Amplitude Modulation.

• Method of broadcasting electrical signals that cannot travel very far on their own. In this method, the signal is imposed or 'imprinted' on a carrier wave whose amplitude increases or diminishes with the amplitude of the signal. AM transmission operates in the 535 to 1705 kilohertz frequency band used for shortwave broadcasting and some citizen band (CB) aviation services. See also frequency modulation.

FM

• Freqeuncy modulation.

• Method of broadcasting electrical signals that cannot travel very far on their own. In this method, the signal is imposed or 'imprinted' on a carrier wave whose frequency increases or diminishes with the frequency of the signal. FM transmission operates in 88 to 108 megahertz frequency band, and is less susceptible to electromagnetic interference than amplitude modulation (AM).

DATA ROUTING 

• The process of moving a packet of data from source to destination. Routing is usually performed by a dedicated device called a router. Routing is a key feature of the Internet because it enables messages to pass from one computer to another and eventually reach the target machine. 
• Each intermediary computer performs routing by passing along the message to the next computer. Part of this process involves analyzing a routing table to determine the best path. Routing is often confused with bridging, which performs a similar function. 
• The principal difference between the two is that bridging occurs at a lower level and is therefore more of a hardware function whereas routing occurs at a higher level where the software component is more important. And because routing occurs at a higher level, it can perform more complex analysis to determine the optimal path for the packet.

BRIDGES 

• Product that connects a local area network (LAN) to another local area network that uses the same protocol (for example, Ethernet or token ring). You can envision a bridge as being a device that decides whether a message from you to someone else is going to the local area network in your building or to someone on the local area network in the building across the street. 
• A bridge examines each message on a LAN, "passing" those known to be within the same LAN, and forwarding those known to be on the other interconnected LAN (or LANs). In bridging networks, computer or node addresses have no specific relationship to location. 
• For this reason, messages are sent out to every address on the network and accepted only by the intended destination node. Bridges learn which addresses are on which network and develop a learning table so that subsequent messages can be forwarded to the right network.