Transcript Slide 1
Slide 1 Chapter 6 Telecommunications and Networking Well, Sort-of Slide 2 Chapter 6 Telecommunications and Networking What is Telecommunications?? The exchange of information in any form (voice, data, text, images, audio, video) over networks Slide 3 Chapter 6 Telecommunications and Networking Network Concepts • A network is an interconnected or interrelated chain, group, or system • The number of possible connections on a network is N(N–1) or N2 –N • N = number of nodes (points of connection) • Example: 10 computers on a network = 10(10–1) = 10x9 = 90 possible connections Slide 4 Chapter 6 Telecommunications and Networking Network Concepts • Metcalfe’s Law • The usefulness, or utility, of a network equals the square of the number of users • The more users on a network, the more useful it becomes • Until critical mass is reached, a change in technology only affects the technology • Once critical mass is attained, social, political, and economic systems change • Example: The Internet is growing exponentially. We can expect more value, for less cost, virtually every time we log on. Slide 5 Chapter 6 Telecommunications and Networking Network Concepts • Open Systems • use common standards for hardware, software, applications, and networks • Internet networking technologies are a common standard for open systems • Connectivity • Open systems provide greater connectivity and network interoperability • Middleware may be needed to help diverse systems work together Slide 6 Chapter 6 Telecommunications and Networking Network Concepts • Middleware • A general term for any programming that mediates between two separate programs • Allows a particular database to access other databases without custom programming • Commonly known as the “plumbing” of an information system • routes data and information between back-end data sources and end user applications • An essential component of any IT infrastructure Slide 7 Chapter 6 Telecommunications and Networking Digital Network Technologies • Local Area Network (LAN): networks connecting information processing devices within a limited physical area Star: ties end user computers to a central computer (hierarchical) Ring: ties local computer in a relatively equal basis Bus: computers share the same communications channel Slide 8 Chapter 6 Telecommunications and Networking What Types of Telecommunications are there?? • Wide Area Network (WAN): networks that covers a large geographic area Slide 9 Chapter 6 Telecommunications and Networking What Types of Telecommunications are there?? • Virtual Private Network (VPN): secure network that uses the Internet as its main backbone network, but relies on network firewalls, encryption, and other security features of its Internet and intranet connections and those of participating organizations • Creates a private network without the high cost od a separate Proprietary Connection • UTEP VPN Slide 10 Chapter 6 Telecommunications and Networking What Types of Telecommunications are there?? • Client Server Networks: PCs and workstations, called clients are interconnected by local area networks and share application processing with network servers Slide 11 Chapter 6 Telecommunications and Networking What Types of Telecommunications are there?? • Network Computing: Thin clients provide a browser-based user interface for processing small application programs A thin client, sometimes also called a lean client, is a computer (client) in client-server architecture networks which depends primarily on the central server for processing activities. Slide 12 Chapter 6 Telecommunications and Networking What Types of Telecommunications are there?? • Peer-to-Peer: file-sharing software connects each PC to a central server or to another online user’s PC A pure peer-to-peer network does not have the notion of clients or servers, but only equal peer nodes that simultaneously function as both "clients" and "servers" to the other nodes on the network. Some networks and channels use a client-server structure for some tasks (e.g. searching) and a peer-to-peer structure for others. Slide 13 Chapter 6 Telecommunications and Networking What are the components of a Telecommunications System? • Terminals: any input/output device that uses telecommunications networks to transmit or receive data • Telecommunications Processors: devices that perform control and support functions Include: • Modems • Switches • Routers • Others Slide 14 Chapter 6 Telecommunications and Networking What are the components of a Telecommunications System? • Telecommunications Processors: Modems (MOdulation-DEMolulation): convert digital signals from a computer into analog frequencies that can be transmitted over ordinary telephone lines Slide 15 Chapter 6 Telecommunications and Networking What are the components of a Telecommunications System? • Telecommunications Processors: Multiplexers: allows a single communications channel to carry simultaneous data transmissions from many terminals Switches: makes connections between telecommunications circuits in a network In a telecommunications network, a switch is a device that channels incoming data from multiple input ports to the specific output port taking data to its intended destination. Regular telephone services rely on circuit switching where a switch opens a link between a sender and receiver Slide 16 Chapter 6 Telecommunications and Networking What are the components of a Telecommunications System? • Telecommunications Processors: Switching alternatives: Message Switching: a message is transmitted a block at a time from one switching device to another Packet Switching: messages are divided into fixed or variable length packets, and packets are sent across networks Cell Switching: breaks voice, video and other data into fixed cells of 53 bytes and routes them to their next destination in the network Slide 17 Chapter 6 Telecommunications and Networking What are the components of a Telecommunications System? • Telecommunications Processors: Router: intelligent communications processor that interconnects networks based on different protocols Slide 18 Chapter 6 Telecommunications and Networking What are the components of a Telecommunications System? • Telecommunications Processors: Hub: a port switching communications processor a device for connecting multiple twisted pair or fiber optic Ethernet devices together, making them act in unison Gateway: connects networks using different communications architectures a network node equipped for interfacing with another network that uses different protocols. Slide 19 Chapter 6 Telecommunications and Networking What are the components of a Telecommunications System? • Telecommunications Channels: media over which data are transmitted and received Twisted Wire: copper wire twisted into pairs From 2M bits/Second (BPS) (unshielded) to 100M BPS (Shielded) Coaxial Cable: sturdy copper or aluminum wire wrapped with spacers to insulate and protect it From 200Mbps to 500Mbps Fiber Optics: one or more hair-thin filaments of glass fiber wrapped in a protective jacket Up to Trillions BPS (Tbps) ½ inch cable can carry 500,000 Channels Future: Each fiber can be split into 1,000 channel Slide 20 Chapter 6 Telecommunications and Networking What are the components of a Telecommunications System? • Telecommunications Channels: Bandwidth: Classification of communications speed and capacity of telecommunications networks Narrow Band: low-speed (BPS) Broadband: High-speed (BPS) Slide 21 Chapter 6 Telecommunications and Networking What are the components of a Telecommunications System? • Wireless Telecommunications Channels: Terrestrial Microwave: earthbound microwave systems that transmit highspeed radio signals in a line-of-sight path between relay stations spaced approximately 30 miles apart Communications Satellites: highearth orbit communications satellites placed in stationary geosynchronous orbits Slide 22 Chapter 6 Telecommunications and Networking What are the components of a Telecommunications System? • Communications Satellites: More than 21,000 orbital debris larger than 10 cm (3.94 in.) are known to exist. The estimated population of particles between 1 and 10 cm in diameter is approximately 500,000. The number of particles smaller than 1 cm exceeds 100 million. (Source: NASA) The worst know collision occurred on 10 February 2009 when an operational U.S. Iridium satellite and a derelict Russian Cosmos satellite collided. Slide 23 Chapter 6 Telecommunications and Networking What are the components of a Telecommunications System? • Wireless Telecommunications Channels: Cellular and PCS Systems: a geographic area divided into cells with one low-power transmitter device per cell used to relay calls from one cell to another Wireless LANs: high- or low-frequency radio technology installed in an office or building Wireless Webs: wireless, Web-enabled information appliances accessing the Internet, intranets and extranets Slide 24 Chapter 6 Telecommunications and Networking What are the components of a Telecommunications System? • Telecommunications Control Software: programs that control telecommunications activities Traffic Management: manage network resources and traffic to avoid congestion and optimize telecommunications service levels to users Security: provide authentication, encryption, firewall, auditing and enforcement Slide 25 Chapter 6 Telecommunications and Networking What are the components of a Telecommunications System? • Telecommunications Control Software: Network Monitoring: troubleshoot and watch over the network, informing network administrators of potential problems before they occur Capacity Planning: survey network resources and traffic patterns and users’ needs to determine how best to accommodate the needs of the network as it grows and changes Slide 26 Chapter 6 Telecommunications and Networking What are Network Architectures & Protocols?? • Protocols: standard set of rules and procedures for the control of communications in a network • Network Architecture: the use of standard protocols, standard communications hardware and software interfaces and the design of a standard multilevel interface between end users and computer systems with the goal of promoting an open, simple, flexible, and efficient telecommunications environment Slide 27 Chapter 6 Telecommunications and Networking What are Network Architectures & Protocols?? • Open Systems Interconnection (OSI): model is a seven-layer model that serves as a standard model for network architectures • Transmission Control Protocol / Internet Protocol (TCP/IP): is a five layer telecommunications protocol used by the Internet Slide 28 Chapter 6 Telecommunications and Networking How are telecommunications applied?? • Business Uses of the Internet: Slide 29 Chapter 6 Telecommunications and Networking How are telecommunications applied?? • Business Value of the Internet: Slide 30 Chapter 6 Telecommunications and Networking How are telecommunications applied?? • Intranet: A network inside an organization that uses Internet technologies to provide an Internet-like environment within the enterprise for information sharing, communications, collaboration, and the support of business processes Includes firewall for security Slide 31 Chapter 6 Telecommunications and Networking How are telecommunications applied?? • Extranet: Network links that use Internet technologies to interconnect the intranet of a business with the intranets of its customers, suppliers, or other business partners Slide 32 Chapter 6 Telecommunications and Networking How are telecommunications applied?? • Business Value of Telecommunications: Slide 33 Chapter 6 Telecommunications and Networking What are the trends in Telecommunications?? • Open Systems: Information systems that use common standards for hardware, software, applications, and networking • Connectivity: The ability of networked computers and other devices to easily access and communicate with each other and share information • Interoperability: The ability of an open system to enable the many different applications of end users to be accomplished using the different varieties of computer systems, software packages, and databases provided by a variety of interconnected networks Slide 34 Chapter 6 Telecommunications and Networking What are the trends in Telecommunications?? • Digital Network Technologies: Digital transmission technologies that transmit information in the form of discrete pulses • Benefits: Higher transmission speeds Movement of larger amounts of information Greater economy Lower error rates Slide 35 Chapter 6 Telecommunications and Networking What are the trends in Telecommunications?? Slide 36 Chapter 6 Telecommunications and Networking QUESTIONS???