
CCNA certification
Network definition: A group of two or more computer systems linked together. Computers linked need a way to share data through communications media such as copper wires, radio waves, fiber-optics, wifi, etc. Data including documents, pictures, videos, files, etc. Nodes-laptops, PC, server, router, modem, printer, etc
Internet
Biggest computer network worldwide. Web server is available to anyone. Web hosting is how you get info on web server. ex.) go daddy-lots of memory.
Servers
Browsers job is accessing data through wireless from computer to servers. Send request to server, server sends files to computer, web browser interprets files to texts and pictures.
Peer to peer networks
Network hosts don’t have specific role. They both provide network services and consume. For example shared printer on one computer and shared hard drive on another. Benefits: simplicity-no trouble to configure, inexpensive-installation only. Drawbacks-manageability-difficult to support because lack administrator/no central computer.
Client-server network
Network hosts have specific roles. Certain hosts are assigned to be servers-provides network resources. Clients-consumes network services; windows professional, etc. Different operating systems. Servers have special designed operating systems ex.) netware, linux, etc highly scalable, easy to add more servers because servers are centralized.
Geography
LAN(local area network)- resides in small geographic area ex.) one particular business, several floors etc perhaps college campus sharing printer (internetworking). Connected by cable or wireless.
WAN(wide area network)-group of LANS separated geographically widely ex.) range from different states. Benefits: access file in another location because they are internetworked
MAN(metropolitan area network)-larger than LAN, often span large cities, computers are all connected.
Signaling
Baseband-one signal at a time on network medium signal used entire medium at the same time ex.) old telephones one signal on wire at time
Broadband-divides network medium into multiple channels, multiple signals being transmitted on same medium at the same time ex.) cable provider
NIC(network interface cards)
Part of computer that allows you to connect to the internet. Connects to the motherboard and ethernet port or wireless network interface cards which allows you to connect to a network with a communications media. In Device manager on Windows shows all parts of computer-network adapters shows card built into the desktop.
Protocols-
Rules for communication. set of exchanges between computers. MAC--->web server.
Step 1.)MAC requests to connect to server Step 2.) web server accepts being connected to
Step 3.)MAC requests to Get file Step 4.) Web server sends files
http://www.thenewboston.com/index.php
http:// hypertext transfer protocol- set of rules computer has to use to access name of the server(www.thenewboston.com) /index.php- file
Topology/Layout-the way you will connect/design the computers/networks. Cost, installation, ease of maintenance.
Bus-one main cable(ethernet) devices “nodes” will be connected along this cable/wire. ex.) Home or office. Terminators are devices to put at the ends of the cables signal bounces off ends and mirrors back if there is a lack of terminators bad because multiple messages will be sent. When requesting data, signal travels through every node but server will be the only one who responds. Not the best topology to use-outdated.
Ring
Devices are all connected to two main ring in center. No logical beginning and end making it better than bus topology. Signal travels node by node and continues until it returns to the source.
Star
Common topology for home networks. Many different nodes connected to central device etc router. Ethernet or wireless connects devices to router. Looks like a star. Low costs. Easy to expand. The rest of the nodes aren’t affected by one damaged nodes on the network. Downside
is that entire network is dependent on one router so every node won’t work if router is damaged.
Mesh
Signal can provide alternate routes in case cable breaks so there is build in protection. Looks kind of like a jewish star. More nodes equals more communication paths in case one gets damaged. Downside is it is very expensive need a lot of cables and NIC cards. Not used in LAN mostly WAN and MAN.

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