Chapter 7 - Telecommunications, The Internet, & Wireless Technology
Transmission speed: • Frequency
(Hertz, Kilo hertz, Mega hertz, Giga hertz) • Cycles per second (hertz) • Kilo = 1,000; (10^3) Mega = 1,000,000; Giga = 1,000,000,000 • E.g., 2.4 Ghz of most cordless phones
Department of Defense reference model for TCP/IP (Four layers)
1. Application layer 2. Transport layer 3. Internet layer 4. Network interface layer
Six Major components in a simple network
1. Client computer(s) 2. Server computer(s) 3. Network Interfaces 4. Connection medium 5. Network operating system(s) 6. Hubs, Switches, Routers
Three Networking & Communication Trends
1. Convergence: Telephone networks and computer networks converging into single digital network using Internet standards - E.g. cable companies providing voice service 2. Broadband: More than 75% of US Internet users have broadband access 3. Broadband Wireless: Voice and data communication as well as Internet access are increasingly taking place over broadband wireless platforms
Six Components of networks in large companies
1. Hundreds of local area networks (LANs) linked to organization wide corporate network 2. Various powerful servers (Web sites, Corporate intranet, extranet, Backend systems) 3. Mobile wireless LANs (Wi-Fi networks) 4. Videoconferencing system 5. Telephone network (VOIP) 6. Wireless cell phones
Web 2.0 Four defining features
1. Interactivity 2. Real-time user control 3. Social participation (sharing) 4. User-generated content
Mobile search (% of all searches in 2012/2015)
20% of all searches in 2012; 50% in 2015
Hotspots
Access points in public place to provide maximum wireless coverage for a specific area
Uniform resource locators (URLs)
Addresses of Web pages • E.g. http://www.megacorp.com/content/features/082602.html
Search Engine Optimization (SEO)
Adjusting web site and traffic to improve rankings in search engine results and to generate more site visitors
Web 2.0 Services & Tools: • Blogs
Chronological, informal Web sites created by individuals • RSS (Really Simple Syndication) • Blogosphere • Microblogging
Largest implementation of client/server computing
The Internet
Web 2.0 Services & Tools: • Wikis
collaborative Web sites where visitors can add, delete, or modify content on the site
Newsgroups
discussion groups on electronic boards
Web 2.0 Services & Tools: • Social networking sites
enable users to build communities of friends and share information
Chatting and instant messaging
interactive conversations
Peer-to-Peer LANS
network that treats all processors equally and is used primarily in small networks of 10 or fewer users.
person-to-person messaging, document sharing
Telnet/SSH/RDP
remote access protocols
World Wide Web (HTTP)
retrieving, formatting, and displaying information (including text, audio, graphics, and video) using hypertext links
Client/Server LANS
the network operating system resides primarily on a single file server, and the server provides mush of the control and resources for the network
File Transfer Protocol (FTP)
transferring files
Microblogging
type of blogging that features short posts of 140 characters or fewer
Web 3.0: the Semantic Web
• A collaborative effort led by W3C to add layer of meaning to the existing Web • Goal is to reduce human effort in searching for and processing information • Making Web more "intelligent" and intuitive • Increased communication and synchronization with computing devices, communities • "Internet of Things" (IoT) • Increased cloud computing, mobile computing
Semantic search
• Anticipating what users are looking for rather than simply returning millions of links • Search technology capable of understanding human language and behavior
Cellular systems: • Competing standards for cellular service
• CDMA (Code Division Multiple Access): United States Only (Verizon); More efficient than GSM • GSM (Global System for Mobile Communicaitons): Rest of world, AT&T, T-Mobile; Strength is in international roaming capability
Transmission Control Protocol/Internet Protocol (TCP/IP)
• Common worldwide standard that is basis for Internet • The standard/common language for the world wide web
Metropolitan-area networks (MANs)
• Connect a city or metropolitan area; • Geographical scope falls between a LAN and WAN
Local-area networks (LANs)
• Connect personal computers and other digital devices within a half-mile (500-meter) radius; • E.g. an office or floor of a building • Ethernet is standard for physical mediums • Client/Server vs. Peer-to-Peer
Campus-area networks (CANs)
• Connect up to a mile (100-meter) radius; • E.g. a college campus or corporate facility
Wide-area networks (WANs)
• Connects regional, transcontinental, or global areas • The internet is the most useful and powerful WAN
The Domain Name System
• Converts IP addresses to domain names • Hierarchical structure • Top-level domains
Client/server computing
• Distributed computing model • 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 • Has largely replaced centralized mainframe computing
Cellular systems: • 4G networks and LTE
• Entirely packet-switched • Transmission speeds of 100 Mbps - 1Gbps
Bluetooth (802.15)
• Links up to 8 devices in 10-meter area • Useful for personal networking (PANs) and in business to transmit data from handheld devices to other transmitters
Four Types of networks
• Local-area networks (LANs) • Campus-area networks (CANs) • Metropolitan-area networks (MANs) • Wide-area networks (WANs)
Search Engine Marketing
• Major source of Internet advertising revenue • Use of search engines to deliver sponsored links, for which advertisers have paid, in search engine results
Internet Architecture and Governance
• No formal management: Internet Architecture Board (IAB), Internet Corporation for Assigned Names and Numbers (ICANN), WWW Consortium W3C • IAB: helps define the overall structure of the Internet ICANN: manages the domain name system W3C: sets Hypertext Markup Language and other programming standards for the web • The Future Internet: IPv6 and Internet2
RSS (Really Simple Syndication)
• Pulls specific content from websites and feed it automatically to users' computers; • Syndicates Web content so aggregator software can pull content for use in another setting or viewing later
DNS Hierarchical structure
• Root Domain: "." • Top-level Domains: edu, com, gov, org, net, etc. • Second-level Domains: expedia, google, congress (google.com) • Third-level Domains: sales (sales.google.com) • Hosts: Designates a specific computer on either the Internet or a private network (computer1.sales.google.com)
Voice over Internet Protocol (VoIP)
Digital voice communication using IP and packet switching. (cable providers, google, skype)
Social search
Effort to provide more relevant and trustworthy search results based on a person's network of social contacts • Google +1, Facebook Like
Domain Name
English-like name that corresponds to the unique 32-bit numeric IP address for each computer connected to the internet
HTML (Hypertext Markup Language)
Formats documents and incorporates dynamic links to other documents and pictures for display on Web
Internet
Global network of networks using universal standards to connect millions of networks
Packet switching
Method of slicing digital messages into parcels (packets), sending packets along different communication paths as they become available, and then reassembling packets at destination; • Previous circuit-switched networks required assembly of complete point-to-point circuit; • Packet switching more efficient use of network's communications capacity
IPv6 (Internet Protocol version 6)
New IP addressing system using 128-bit IP addresses; Replacing the old addressing system
Internet of Things (IoT)
Pervasive web in which each object or machine has a unique identity and is able to use the Internet to link with other machines and send data
Internet2 (I2)
Research network with new protocols and transmission speeds that provides an infrastructure for supporting high-bandwidth Internet applications
Protocols
Rules and procedures that govern transmission of information between two points
Virtual private network (VPN)
Secure, encrypted, private network run over Internet
Web servers
Software for locating and managing Web pages
Key digital networking technologies
Client/server computing Packet switching TCP/IP and connectivity
Hypertext Transfer Protocol (HTTP)
Communications standard used for transferring Web pages
TCP/IP and connectivity
Connectivity between computers enabled by protocols
Transmission speed: • Transmission speed in bits per second (Bps)
Cycles per second * bits per cycle: • Kbps: 1000 bits per second • Mbps: 1000 Kbps • Gbps: 1000 Mbps
Digital versus Analog signals: • Modem
Device that translates digital signals into analog form (and vice versa) so that computers can transmit data over analog networks such as telephone and cable networks
Routers
Device used to route packets of data through different networks, ensuring that data sent gets to the correct address
Access points
Device with radio receiver/transmitter for connecting wireless devices to a wired LAN
Transmission speed: • Bandwidth
Difference between highest and lowest frequency in a transmission channel • Greater the difference, greater the bandwidth
Blogosphere
The totality of blog-related websites
What is a computer network?
Two or more connected computers
Intelligent agent shopping bots
Use intelligent agent software for searching Internet for shopping information
Web 2.0
• Second-generation, Internet-based services • Enabling collaboration, sharing information, and creating new services online
Wi-Fi (802.11)
• Set of standards: 802.11a, 802.11b, 802.11g, 802.11n • Used for wireless LAN and wireless Internet access • Use access points • Hotspots • Weak security features
Cellular systems: • Third-generation (3G) networks
• Suitable for broadband Internet access; To slow for videos • Transmission speeds of 144 Kbps - 2Mbps
Search engines
• Tools for locating specific sites or information on the internet • Started in early 1990s as relatively simple software programs using keyword indexes; • Google improved indexing and created page ranking algorithm system.
Transmission Media: Types and Speeds
• Types: twisted pair, coaxial cable, fiber cable, wireless • Speeds: wide range of speeds depending on software/hardware combination
WiMax (802.16)
• Wireless access range of 31 miles • Require WiMax antennas • Sprint Nextel building WiMax network as foundation for 4G networks
