Chapter 3 Telecommunications and Networking PDF

RepublicofthePhilippines TARLAC STATE UNIVERSITY COLLEGE OF BUSINESS AND ACCOUNTANCY Tarlac City Narrative Report: Telecommunications and Networking Submitted by: Cirineo, Camille Frank P. C...

RepublicofthePhilippines TARLAC STATE UNIVERSITY COLLEGE OF BUSINESS AND ACCOUNTANCY Tarlac City Narrative Report: Telecommunications and Networking Submitted by: Cirineo, Camille Frank P. Constante, Rolhen Jeyk M. Corpuz, Angelica DC. BSAIS 3-A (Group 3) Submitted to: Liezl D. Taruc Telecommunications and Networking (CIRINEO, Camille Frank Payabyab) Communications - transmission of a signal by way of a medium from a sender to a receiver. TeleCommunications - electronic transmission of signals for communications, including such means as:  Telephone  Radio  Television  Computer Network The prefix tele - simply means operating at a distance. Networking - the electronic linking of geographically dispersed devices—is critical for modern organizations. Computer networking - refers to interconnected computing devices that can exchange data and share resources with each other. These networked devices use a system of rules, called communications protocols, to transmit information over physical or wireless technologies. 5 Primary reasons for networking:  sharing of technology resources  sharing of data  distributed data processing and client/server system  enhanced communications  marketing outreach Functions of a Telecommunications Network:  Transmission  Processing  Editorial  Conversion  Routing  Network Control  Interface KEY ELEMENTS OF TELECOMMUNICATIONS AND NETWORKING 1. Analog and Digital Signals a. Analog Signal  Signals of varying frequency (pitch) and amplitude (loudness)  Continuous (infinite number of values)  “Analogous” to the original data e.g. phone lines carry electronic signals analogous to the original voices b. Digital Signals  Signals with only two possible values  Discrete (fixed number of values)  Repeaters can clean up noise *Two solutions are possible to the problem of transmitting computer data. The original solution, and one that is still used, is to convert the data from digital form to analog form before sending it over the analog telephone network. This conversion is accomplished by a device called a modem. What a Modem Does? Modulates a digital signal into an analog signal for transmission via analog medium, then demodulates the signal into digital for receiving. 2. Speed of Transmission - Whether the signal is digital or analog, another basic question is the speed of transmission. Please note that by speed we do not mean how fast the signal travels in terms like miles per hour, but rather the volume of data that can be transmitted per unit of time.  BANDWITH - the circuit capacity.  BAUD - number of signals sent per second and formerly used for relatively slow speeds such as 2,400 baud or 14,400 baud (bps).  HERTZ - cycles per second. They are used for higher speeds such as 500 megaHertz (500 million bps) or 2 gigahertz (2 billion bps). Hertz is still widely used in PC advertisements. 3. Types of Transmission Lines  SIMPLEX TRANSMISSION - rarely useful. It is a one-way transmission.  HALF-DUPLEX TRANSMISSION - one way at a time.  FULL-DUPLEX TRANSMISSION - two-way transmission. It provides greater capacity, but it costs more than half-duplex lines. 4. Transmission Media - A telecommunications network is made up of some physical medium (or media) over which communications are sent. Five primary media are in use today: twisted pair of wires, coaxial cable, wireless, satellite (which is a special form of wireless), and fiber-optic cable. a. Twisted Pair  the most common transmission medium.  the purpose of the twisting is to reduce electrical interference from similar twisted pairs nearby  consists of two insulated copper wires, typically about 1 millimeter thick, twisted together in a long helix.  Insulated pairs of wires are historically used in telephone service. Category 1 – Telephones Category 3 – Up to 10Mbps Category 5 – Up to 100Mbps b. Coaxial Cable - consists of a heavy copper wire at the center, surrounded by insulating material. Around the insulating material is a cylindrical conductor, which is often a woven braided mesh. Then the cylindrical conductor is covered by an outer protective plastic covering. Two Kinds of Coaxial Cable a. Baseband Coax - for digital transmission. b. Broadband Coax - originally used for analog transmission but is now used for digital transmission as well. (Corpuz, Angelica DC.) WIRELESS - is not a transmission medium. It is a broadcast technology in which radi signals are sent out into the thin air. Wireless communicatins is used in a variety of circumstances, including cordless telephones, cellular telephones, wireless LANs, and microwave transmission of voice and data.  CORDLESS TELEPHONE - a portable device which may be used up to about 1,000 feet from its wired telephone base unit. This permits the user to carry the telephone to various rooms in a house or take it outdoors on the patio.  CELLULAR PHONE - may be used anywhere as long as it is within range—about eight to ten miles—of a cellular switching station.  SMARTPHONES - combine a cell phone with a handheld computer and have the ability to access the Internet over the so-called 2G (second generation) or 3G (third generation) networks operated by the cellular carriers. Wireless LANs  have the obvious advantage of being reasonably easy to plan and install.  provides networking where cable installation would be extremely expensive or impractical, such as in an old building.  permits users of mobile devices such as handheld or laptop computers to connect to the LAN (and thus the Internet) whenever they are within range of a wireless access point (WAP), such as in a coffee shop or an airport terminal   less secure than a wired LAN  most wireless LANs operate in the range of 6 to 100 mbps, with some of the newer wireless LANs operating at speeds up to 300 mbps. MICROWAVE - line-of-sight transmission—there must be an unobstructed straight line between the microwave transmitter and the receiver. It is widely used for long-distance telephone communication and, to a lesser extent, for corporate voice and data networks; transmission speeds up to 1 gbps are possible. SATELLITE - special variation of wireless transmission employs satellite communication to relay signals over very long distances. FIBER OPTICS - last and newest transmission medium and is a true medium, not broadcast technology. Fiber optics are much faster than other media and require much less space because the fiber-optic cable is very small in diameter. Fiber-optic cables are more secure because the cables do not emit radiation and, thus, are very difficult to tap. Types of Networks (Rolhen Jeyk M. Constante) 1. COMPUTER TELECOMMUNICATIONS NETWORK  a network emanating from a single medium, large or very large computer /group of closely linked computers  usually arranged as a tree  puts tremendous communication control burden on the central network 2. LAN (Local Area Network)  Local network completely owned by a single organization, operates within 2-3 miles in diameter  have higher data rate of millions bps LAN vs Computer Telecomm 2 types of LAN  Wired  Wireless 5 LAN Standards by Institute for electrical and Electronic Engineers (IEEE) 1. IEEE 802.3 (Content bus design) 2. IEEE 802.4 (Token bus design) 3. IEEE 802.5 (Token ring design) 4. IEEE 802.11 (Wifi wireless design) 5. IEEE 802.16 (wiMAX wireless design) vivamax? 3. BACKBONE NETWORKS - in between networks (middle distance networks interconnecting LANs in a single organizations WAN HUB- forwards all message WAP- connect LAN to other network Bridge- connect LAN segments Router/ gateway- 2 or more LAN segments Switch- connect multiple low speed 4. WIDE AREA NETWORKS (WAN) - long haul networks to communicate both voice and data across their far-flung operation LAN vs WAN - Multi access channel v.s. point-to-point 1.DDD and WATS DDD (Direct Distance Dialing)- 56 kbps paid when used WATS (Wide Area Telephone Service)- monthly fee 2.Leased lines - generally coaxial cables, microwave or fiber optic cables of very high capacity and less prone to data errors compared to ordinary voice lines Expensive one example is T-1 Line , other is SONET (Synchronous Optical Network) 3. Satellite - user organization provides own ground stations/ leases time on carrier ground station and communication lines. Uses VSAT (very small aperture terminal or a small satellite dish) 4.ISDN (integrated services digital network) - set of international standards for telephone users. 5.Packet-switched networks  permits multiple connections to exist simultaneously over the same physical circuit  store-and-forward data transition technique.  packet assembly/ disassembly device (PAD) is used to connect the user organizations internal network on each location- to a common carrier network  \ 6.Virtual private network (VPN)  Equivalent of private packed switch network using the public internet  The user org places a VPN gateway on each internet acces circuit to provide access from org network to VPN gateway, create VPN tunnels through internet, these ensures only authorized users can access circuits 5. INTERNET - network of networks using TCP/IP protocol with gateways to even more networks that do not use such protocol History: 1969 ARPANET (U.S. Department of Defense) 1986 NSFNET is the backbone of emerging internet Provides 4 basic functions:  electronic mail  remote log-in  discussion groups  sharing data resources WWW(worldwide web/WEB) - hypertext-based way of traversing/surfing URL (Universal Resource Locator) Blog,wiki,social networking apps, WEB 2.0 (2nd gen of web-based services- online collab) Accessing internet  Connect to LAN-backbone-internet BROADBAND CONNECTION: DSL (digital subscriber line) - a cable modem, satellite, wireless and fiber to the home Intranet - a network operating within org with TCP/IP protocol 6. INTERNET2 - not a network type, hopes to accelerate creation of Tomorrow internet(information superhighway) 3 primary goals:  Create leading-edge network for national research community  Enable revolutionary internet apps  Ensure rapid transfer of new network services How do these elements actually communicate with each other? NETWORK PROTOCOLS -agreed upon set of rules governing communication among layers/levels of network. Use both protocol to communicate 1. Open systems interconnection (OSI) defines seven layers: 1. Application Layer  deals with wide variety of communication-oriented.  Applications. Use same protocol  2. Presentation layer  accepts input as internally coded, translates to  Standard representation used by network 3. Session Layer  users of different machines may establish sessions  Between them. Can do dialog control, synchronization 4. Transport Layer  receives communication, split to smaller blocks  Called packets, can add special header data to define connections 5. Network Layer  receives packet of data, routes the packet 6. Data link layer  in form of data frames adds special header/ trailer data  Transmits frames in sequence 7. Physical layer  transmits bits (a string of Zero and One) over physical  Communication channel 2. TCP/IP (Transmission control protocol/ Internet Protocol-  Only a partial set of protocols, not a fully developed model  Accepts message of any length, breaks into 64,000 bytes, sends to receiver  Original developers envision as 4 layers: application, networking, transport and then hardware. Extended TCP/IP (additional lang na protocol)  SMTP - email  HTTP - Web pages  FTP - File transfer  TCP - transport layer  IP - network layer  Hardware includes LAN standards (Corpuz, Angelica DC.) THE EXPLODING ROLE OF TELECOMMUNICATIONS AND NETWORKING 4 AREAS of operation in which telecommunications networks are of critical and growing importance: 1. ONLINE OPERATIONS  dominant activities of many organizations have now been placed online to the computer via a network.  computerized reservations systems of the major airlines are another example of an indispensable use of online systems. 2. CONNECTIVITY  most large and midsized (and many smaller) organizations now provide a personal workstation for every managerial and professional employee, and these workstations are connected to a network structure (often an intranet) so that each employee has access to every person, and every system, with which he or she might conceivably need to interact.  connectivity to persons and organizations outside the firm is also important. 3. ELECTRONIC DATA INTERCHARGE AND ELECTRONIC COMMERCE Electronic Data Intercharge (EDI) - set of standards and hardware and software technology that permits business documents (e.g., purchase orders, invoices, and price lists) to be transferred electronically between computers in separate organizations. Electronic Commerce (also called e-business) - a broad term that incorporates any use of telecommunications and networking to conduct commercial activities. EDI is part of electronic commerce, but the most explosive electronic commerce area involves commerce over the World Wide Web. It includes online catalogs, online ordering, online payment for goods and services, and sometimes online delivery of products. 4. MARKETING  all business organizations sell products and services, although the distribution  channels vary widely.  telecommunications is being widely used to provide support for the sales personnel. THE TELECOMMUNICATIONS INDUSTRY 3 MAJOR SEGMENTS of the telecommunications industry: 1. CARRIERS - who own or lease the physical plant (cabling, satellites, cellular towers, and so forth) and sell the service of transmitting communications from one location to another; 2. EQUIPMENT VENDORS - who manufacture and sell a wide range of telecommunications-related equipment, including LAN software and hardware, routers, hubs, wireless access points, switches, multiplexers, cellular telephones, and modems; and 3. SERVICE PROVIDERS - who operate networks and deliver services through the network or provide access to or services via the Internet.