Networks

personal area network

A network designed for communication among devices for one person. E.g. Smartphone, to notebook, to tablet, can use Bluetooth and WIFI

metropolitan area network

A network designed to provide access to a larger geographical area like a city.

local area network

A network where the nodes are located in a small geographical area. E.g. Computer lab at school, restaurant, house Home Area Network (HAN) is a specific type of LAN at your home.

coaxial cable

A single copper wire surrounded by layers of plastic and copper mesh. Used to connect cable TV and cable modems

client/server network

Centrally administrated network Client makes request to the server for information and resources

coaxial cable

Co: Stands for together, coordination Axial: stands for axis All 4 cables share the same axis, all centered around the same point

firewalls

Even if you have only one computer that you can directly connect to the modem, it's still a good idea to have a router because it has a built in hardware firewall. The more ___ you have, the better.

peer to peer network

Every node can communicate directly with every other node. If a computer wants to print it communicates directly with the printer.

mesh topology

Every node is connected to every other node

topologies

Refer to the physical or logical arrangement of computers, cables, and other pieces of the network. Think of this like a floor plan. You want to arrange the equipment for optimal performance.

internet stopped working

Reset both the modem and the router by unplugging them from the power source, then wait 30-45 sec and plug them back in. You may also want to reset you computer.

benefits of networking

Sharing an internet connection among devices Can share resources like printers Can share files Can share software

wide area network

Spans a large physical distance. The internet is the largest WAN. It's a collection of LANs.

nodes

The following list of Network Architectures are defined by the distance between ___ Personal Area Network (PAN) Local Area Network (LAN) Home Area Network (HAN) Metropolitan Area Network (MAN) Wide Area Network (WAN)

bandwidth

The max speed that data can be transmitted between nodes in a network.

computer network

Two or more computers connected via software and hardware so they can communicate with each other. Each device (e.g. computer) connected to a network is called a node.

data collisions

can occur when two computers send out data on the same cable (the bus).

modem

transfers the data to your computer by either Connecting to it directly using USB or Ethernet, or Connecting to a router which will allow multiple computers to connect, and a non-wired Wi-Fi connection.

shielded

twisted pair cable: is less common, it has an insulating material around it that helps further resist the interference.

unshielded

twisted pair cable: is the dominate cable.

router

will take the connect given to it through the modem and split it such that multiple computers can connect.

throughput

Actual speed of data transmission that is achieved.

star topology

Advantages: Failure of one computer doesn't take down the whole network Easy to add nodes to this topology Performance is still good with lots of nodes The switch makes troubleshooting and repairs easier Disadvantage: If the switch fails, the system goes down Requires more cable, thus, can be more costly

bus topology

Advantages: Uses minimal amount of cable Installation is easy, reliable, and inexpensive Disadvantages: Breaks in cable can disable the network Large number of nodes decreases performance, as a lot of data being transmitted on one bus

ring topology

Advantages: Allocates access to network fairly Performance remains ok with lots of nodes No collisions Disadvantage: Adding/removing nodes disables the network Low Redundancy: Failure of one node brings down the network Problems in data transmission can be a hard to find Can take longer to send data if on wrong side of the ring Security: Everyone can see your message, better encrypt it!

mesh topology

Advantages: Data can be going between different nodes at the same time If a node goes down it doesn't destroy the network Disadvantage: Redundancy Cost of all the cables Setting up and maintaining is difficult

bus topology

All computers connected on a sequence on a single cable.

ring topology

Computers are connected along a ring.

modem

Converts the internet signal coming in from the cable into a signal that your computer can understand. And vice versa when you're sending data out.

twisted pair cable

Copper wires twisted around each other Used for telephones An unshielded twisted-pair (UTP) is used for DSL networking

twisted pair cable

Created in 1881 by Alexander Graham Bell Telephones have two wires, one for sending the signal and one for receiving it Telephone wires shared same route as power lines Experienced electromagnetic interference or crosstalk from the magnetic field, e.g. hearing other peoples conversations

cable internet

Data is transferred on the same line that your cable TV signals come in on.

megabits per second

Data transfer rates are traditionally measured in (mbps)

point-to-point

Data travels from one note to another Very simple Supports two nodes

node

Each device (e.g. computer) connected to a network is called a

connecting nodes

In wired networks different types of cables are used based on how close the nodes are. Three types of cables are: Twisted-pair cable Coaxial cable Fiber-optic cable

coaxial cable

More expensive. Here you have 4 layers for one wire, where as with the twisted pair you had two. And the pieces are more expensive. There is less interference here, where as with the twisted-pair when you use it over long distances the interference gets magnified. Invented by Oliver Heaviside in 1880 All the shields reduce signal leakage.

fiber optic cable

Most expensive, and most advanced Plastic or glass fibers that transmit data at extremely fast speeds. The glass will not produce or be altered by magnetic fields Can carry larger amounts of data over larger distances at higher speeds Used as the network backbone

star topology

Nodes all connect to a switch.

Internet Service Provider (ISP)

Organizations that provide companies or individuals with access to the internet. (CSI)

fiber optic cable

Producing glass as thin as hair, and to exact measurements is very costly More fragile since it's glass We are satisfied with what we have today

wifi

Radio internet waves are sent out through your wireless router. Your computer was an internet card, and it picks up the signal.

router

The modem will be connected to the router through Ethernet to a port that either says WAN (Wide Area Network) or Internet. Then your computers can directly connect with Ethernet wires or they can connect wirelessly as long as you have a wireless router.

twisted pair cable

They twisted the wires at each junction to resist the electro magnetic interference.

bus topology

This topology is less used now as it's not designed to easily support wireless Data Collisions can occur when two computers send out data on the same cable (the bus). Because of the setup Data Collisions are more common on Bus Topologies than others. To prevent data collisions an access method is established where the computer checks to see if data is being transmitted before it attempts to transmit.

ring topology

To avoid data collisions this topology uses a token. The token is passed around the ring until a computer takes hold of it. A computer can transmit data when it has the token, and will not give up the token until it is done transmitting.

star topology

To send data from one node to another, it will first go to the switch, and the switch will direct the data to the correct receiving node. To avoid data collisions it uses CSMA/CD (Carrier Sense Multiple Access with Collision Detection). Here the node listens to make sure no data is being sent before it sends data.

digital subscriber line

Uses regular copper phone lines to transfer digital data to and from the phone companies central office. (CSI) With this approach you can still use your phone at the same time as your internet because they use different frequencies.

wifi

is the standard transmission using radio waves to connect nodes Wirless networks typically have decreased throughput when compared to wired networks because: More interference from magnetic and electronics Other people can get on your connections Metal and buildings can decrease your signal

modem

modem connects to the wall for signal in and signal out. Typically, using your coaxial cable.