Chapter 7: Telecommunications and Networking

7.4 The Wireless revolution: -Cellular systems (3G and 4G)

-Cellular systems: use 3g networks (good for browsing not for videos..).. 4g aka LTE, fast! -Bluetooth: creates PANs (personal area networks)- links up to 8 devices within 10 meters. -Wifi: wireless devices commuincate with wired LAN using access points. -Hotspots: access points to wifi -Wimax: wide range wifi

Internet Addressing and Architecture

-Each device on internet assigned a unique Internet Protocol (IP) address -DNS: converts domain names to IP addresses. Domain name is eglish name that corresponds to the IP number. -Hierarchical Structure: root domain (.), top-level (com), second-level (google), third level (sales), Hosts (computer) sales.google.com

The Web What is hypertext? >HTLM, HTTP What is URL? What is Web server? How do you find information on the web?

-Hypertext: Used on webpages based on HTML (hypertext markup language) ... makes webpages accessible through the internet because the host servers stores pages as HTTP (Hypertext Transfer Protocol). -URL: Uniform Resource locator; combines the http prtorocol and the domain name along with any page information and format... Example.. http://www.megacorp.com/content/ features/082610.html, Web Server: software for locating, and managing stored web pages. Finding Info: using search engines that sort through millions o f sites for the ones you're looking for. Mobile searches are taking over! Search engine marketing: revenue generated from ads on search engine platforms. SEO: Search engine optimization: process of improving quality and volume of web traffic to a wbsite by employing serie of techniquesthat help a site get higher ranking when certain phrases are put out

Networks in Large companies

-The simple network defined previously (Local area networks- LANs) are now multiplied by the hundreds and linked to firm-wide corporate network -Many servers support internet, websites or extranet. These servers can link to large computers supporting back-end systems. - Use mobile wireless LANs (Wifi) -telephone networks

7.3 The Global Internet What is the internet? ISP? Variety of ISPs?

-World's most extensive network -ISP: Internet Service Provider: organization with connection to the internet that sells temporary connections. -Dial-up -> digitial subscriber line -> Cable internet -> sattelite -> T1/T3 lines

What are Analog signals vs Digital signals?

-analog and digital are the 2 ways to communicate a message in a network Analog Signals: continuous waveform that passes through a communications medium and has been used for voice communications (eg. telephone, speakers, earphones..) Digital signal: discrete, binary waveform that communicated info as strings of two discrete states (1 bit and 0 bit) represented as on-off electrical impulses >computers use digital signals and *modem* to convert these into analog signals

What is a computer network? What are the major components used in a simple network? SDN?

A network consists of 2+ connected computers Major components: -Client computer -Server computer (computer on a network that performs network functions for client computers.. such as loading web page..) -network interface -connection medium -Network OS (manages communications on the network and coordinate resources) -Hubs, switches, routers (hubs connect network components, switch a more intellegent hub can filter and forward specific data, router communicates with other networks like the internet) Hubs & switches functions are controlled by a central program -Software-defined networking.

Internet Services and Communication Tools

Internet Services: -Email -Chatting and IM -Newsgroups (Discussion groups on electronic bulletin boards) -Telnet (Logging on one comp. and doing work on another) -File Transfer Protocol (FTP) (transferring filed from one computer to another) -WWW (retrieving, formatting, and displaying information using Hypertexts) -VoIP: delivers voice information in digital form using packet switching, avoiding tolls by telephone networks. -Unified Communications: communication systems that integrate voice, data, email conferencing -VPN: secure, encrypted, private network run over internet- PPTP, tunneling

Types of networks: -Local Area Networks >Ethernet? >Peer2Peer? -Wide Area Networks (WANs) or MANs -Campus Area Netowork

LANs: connects personal computers and other digital devices within a half mile radius (eg.. a few computers in an office) (Linux, windows, novell) Ethernet: dominant LAN standard a physical network level P2P: small group computers sharing resources, filed, folders, printers.. WANs: span broad distances. Internet is WAN of them (hehe) CANs: span an entire campus or facility

Internet Architecture and Governance

NEtwork Service providers: -Own trunk lines (high-speed backbone networks..) Regional telephone and cable companies -Provide regional and local access (lease access to ISPs) Professional Organizations and government bodies establish internet standards -IAB -ICANN -W3C

Transmission Media and Transmission Speed What are the physical transmission medias? What is bps -> hertz

Physical transmission medias: -Twisted Pair Wire -Coaxial cable -Fiber optic cable -Wireless transmission media Bps is bits pr second, one cycle is required to transmit bits.... The number of cycles per second sent through a medium is hertz- 1 hertz=1cycle of medium range of frequencies in the channel is bandwidth

RFID and Wireless Sensor networks:

RFID: Radio Frequency Identification: -Provides information for tracking goods movements throughout supply chain. -Use tiny tags with microchips containing data about item and location. -Tag antennas to transmit signals over short distances to RFID readers -Used in automated toll collection, tracking goods WSN -Network of hundreds or thousands of wireless devices -Used to monitor building security, detect substances in air, traffic -have built in processing, storage and radio frequency sensors -Major sources of Big data

Key Digital Networking Technologies: What is Client/server computing? What is packet switching? What is TCP/IP and Connectivity? -What is the layer of the reference model??

Client/Server: -clients linked through network controlled by network server computer -Server sets rules of communication for network and provides every client with an address so others can find it on the network -The internet is largest implementation of client/server Packet Switching: -Method of slicing digital messaged into parcels (called packets), sending them along different communication paths as they become available and then reassembling them once they arrive at destination. -replaced circuit-switched networks (required assembly and expensive) -packet switching more fficient use of network comm. capacity TCP/IP and Connectivity: -Components in network communicate with each other using: -Protocols- rules that govern transmission of information between 2 points -Transmission Control Protocol/Internet protocol (TCP/IP)- common worldwide standard that is basis of the internet. Layers of the TCP/IP model: 1- Application layer: enables client apps to access other layers and defines protocols (HTTP for xample) 2- Transport Layer: provides application layer with communication and packet services 3- Internet layer: responsible for addressing, routing, and packaging data called IP datagrams. Internet protocol used here. 4- Network Interface layer: responsible for placing packets on and recieving them from network medium- which could be any networking technology

What is telecommunication?

Communication involving networks, telephones, TV computers...