Networks, Connectivity, + the Internet

computer network

connects two or more computer systems/devices (communications media, devices, + software)

communications media

any material substance that carries an electronic signal to support communications between a sending + receiving device

network topology

shape or structure or a network

star network

devices connect through a single central device called the hub node

bus network

devices connected to a common backbone, serves as a shared communication medium

mesh networks

multiple access points link a series of devices across a large area

personal area network (PAN)

connects devices close to one person

local area network (LAN)

connects systems + devices within a small area

metropolitan area network (MAN)

connects users + their computers in a geographical area that spans a campus/city

wide area network (WAN)

connects large geographic regions

channel bandwidth

the capacity of a communications channel to carry traffic

the higher the bandwidth, the more traffic that can be carried

measured in megabits per second

network latency

measures how long it takes for a unit of data to get to its destination + back again

measured in milliseconds or thousandths of a second

low latency = small delays, high latency = long delays

wireless communication

transfer of information between two or more points not connected by an electrical conductor, signal sent within a range of frequencies of the electromagnetic spectrum

near field communication (NFC)

very short-range wireless connectivity technology

bluetooth

devices interconnected over distances of 10-30ft at a rate of 2mbps

wi-fi

improves interoperability of wireless local area network products

microwave trannsmission

high frequency air signal

terestrial microwaves

communications satellite

4G wireless communications

delivers more advanced features over 3G, based on the long long term evolution (LTE) standard

5G wireless communications

more bandwidth, lower latency, supports more devices, enables new applications

network operating software

controls network computer systems + devices

network management software

desktop manager monitors individual computers + shared hardware use, scans for viruses, + ensures software license compliance

mobile device management (MDM) software

remotely manages + troubleshoots devices

software-defined networking (SDN)

network administrators manage a network through a controller, no physical access required, automates tasks, enables dynamic response to application requirements, emerging approach to networking

transmission control protocol/internet protocol (TCP/IP)

collection of communication protocols, interconnects network devices on a packet switching network

IP address

64-bit number uniquely identifying a computer, typically divided into four bytes, translated to decimal

69.32.133.79

network interface card (NIC)

circuit board or card installed into a hardware device, specific MAC address is ‘burned’ into a NICs ready only memory

switch

keeps record of the MAC addresses of all the devices connected to it, determines port a frame of data should be directed to

router

directs data packets to other networks until each packet reaches its destination

routing

use dynamic routing to move packets, packets may arrive at the destination devices out of order

world wide web

exists on the internet

server + client software, the hypertext transfer protocol (http), standards + markup languages

all combine to deliver information + services over the internet

client/server architecture

many clients request + recieve services from on the network

domain name system

maps the name people use to locate a website to the IP addres that a computer uses to locate a website

uniform resource locator (URL)

web address specifying the exact location of a web page using letters + words that map to an IP address + a location on the host

hyperlinks

highlighted texts/graphics in a web document, opens a new web page when clicked

hypertext markup lanaguage (html)

standard web page description language, tags indicate how to format text/graphic

extensible markup language (XML)

markup language for web documents, no predefined tag set

cascading style sheet (CSS)

markup language for defining the visual design of a web page/group of pages

search engine

enables a user to find information on the web, specifying keywords related to a topic of interest

search engine optimization (SEO)

process for driving traffic to a web site, improves the sites ranking in search results

intranet

internal corporate network

extranet

built using web technologues, links selected company intranet resources with customers, suppliers, etc.

virtual private network (VPN)

secure connection between two internet points, encapsulates traffic using IP packets, sends packets over the internet