Wikipedia: Local Area Networks
-A computer network that interconnects computers in a limited area such as home, school, office, computer lab.
-Characteristics of LAN
-higher data-transfer rates
-smaller geographic area
-lack of need for physical lines
-Ethernet and Wifi most common technologies
-History:
-Ethernet developed at Xerox from 1973-1975
-DOS based system starting in 1981 meant way many sites grew to dozen or even hundred of computers
-initial driving force for networking sharing storage and printer access
-introduction of Novell software provided even handed support for dozens of competing card/cable types on one platform
-1990's Microsoft introduced Window NT advanced server
-Unix computer work stations from such vendors such as SUN Microsystems were using TCP/IP based networking
-although this market segemtn has since receded, the technologies developed using TCP/IP continue to be influential on the Internet and in both Linux and Apple OSx networking
-WiFi is not the most common technology in residential premises
-requires modem and is well suited to mobile devices and laptops
-Smaller LANs use one or more technologies linked to each other and thus link to a router or modem for Internet access
Wikipedia:Computer Networks:
-Computer network is a collection of hardware components and computer interconnected by communication channels that allow sharing of resources dn information
-Communication protocols define rules and data formats for exchanging information in a computer network and provide the basis for network programming
-computer networking is sometimes considered a sub-discipline of electrical engineering, telecommunications, computer science, since it relies upon the theoretical and practical application of these disciplines
-the Internet is a global system of interconnected computer network that use the standard Internet protocol suite (TCP/IP) to serve billions of users worldwide
-Properties of computer networks:
facilitate communication
permit shairng of files, data and other types of information
sharing network and computing resources
may be insecure
may interfere with other technologies
may be difficult to set up
-A well known family of communication media is collectively know as Etehrnet;
-utilizes various standards and media that enable commuication between devices
-wireless LAN technology is designed to connect devices without wiring-by use of radio waves or infrared signals as a transmission medium
-Features of communication protocols is that they may be staked above each other : one in use to carry another ie:HTTP running over TCP over IP
-Communication protocols have various propteries
-connection oriented vs connectionless
-circuit mode or packet switching
-hierarchical or flat address
*Communication protocols
-Ethernet: for many users mos twell known member of the protocol family (wireless LAN)
-Internet Protocol Suite: included TCP/IP, foundation of all modem inter networking, at its core the protocol suite defines the addressing, identification and routing specifications in form of the tradition Internet protocol version
-Synchronous Optical Networking: SONET and ADH standardized multiplexing protocols that transfer multiple digit bit streams over optical fibers using lasers
-SONSET/SDH: primarily to support real time, uncompressed circuit - switched voice encoded to PMC format
-Asynchronous Transfer Mode (ATM): is a switching techniques for telecommunication networks, encodes data into small fixed sized cells, ATM has similarities with both circuit and packet switching networks, a good choice for a network that must handle both tradition high data traffic and real time lwo latency content such as voice and video, plays a role in the last leg of the user Internet connection between the service provider and the home user
-Network Programming:writing programs that communicate with each other across a computer network
-Scale: usage, trust level, access rights, differ between types of networks
*Personal Area Network (PAN)
-computer network used for communication among computer and different information tech devices for one person, includes wireless and wired devices
*Storage Area Network (SAN)
-is a dedicated network that provides access to consolidated blocks level data storage
-primarily used to make storage devices accessible to servers so that the device appears like locally attached device to the operating system
*Campus Network
-a computer network made up of an interconnection of LANS within a limited geographical area
*Backbone Network
-part of a computer network infrastructure that interconnects various pieces of the network
-provides a path for the exchange of information between different LANS of sub networks
-backbone capacity is greater than that of the networks connected to it
*Metropolitan Area Network (MAN)
-large computer network that usually spans s city or a large network
*Wide Area Network (WAN)
-computer network that covers a large geographic area (city, country....)
-WAN often uses transmissions facilities provided by common carriers such as telephone companies
*Enterprise Private Network
-is a network built by an enterprise to interconnect various company sites in order to share computer resources
*Internet work
-is a connection of multiple computer networks via a common routing technology using routers
*Organizational Scope
-networks are managed by the organization which owns them, seen as intranet or extranets
*Intranet & Extranet
-intranet is a set of networks that is under direct control of a single admin.
-commonly is the internal network of organization
-larger intranet will have at least one web server to proceed users with organization info
-extranet is lilmed in scope to pa single organization and also has limited connections to the network of one or more trusted outside organization
*Intranet
-global system of interconnected government academic, corporate, public or private computer networks
*Network topology: bus, star, ring, mesh, fully connected network
*Overlay network
-is a virtual computer network that is built on top of another network
*Basic Hardware Component
-Network interface cards:disguised to allow computer to physically access a network medium
-Bridge: connects multiple network segments at eh data level layer
*Switch
-a device that forwards and filters chunks of data between ports based on the MAC addresses in the packet
*Firewall
-important in respect to security, typically rejects access requests from unsafe sources while allowing access from recognized ones
-role of firewalls grows in parallel with constant cyber attacks for the purpose of stealing, corrupting daa dn planting viruses
*Network Security
-provisions and policies adopted by the network administration to protect and monitor unauthorized access, misuse, modification denial of network and network accessible resources
-Resilience
-is the ability to provide and maintain an acceptable level of service in the face of faults and challenges to nominal operations
Journal of Academic Leadership: Management of RFID in Libraries - Karen Coyle
-RF: radio frequency
-ID means identifies the tag itself consists of a computer chip and an antenna
-RFID is like a bar code but is read with an electromagnetic field rather than by a laser beam
-does not have to be visible to be read
-can be read even if embedded in an item
-carry not only item number used but also info such as the title of the book and/or its call number
-the size of the info payload of the rfid chip - a fracture will expand as the tech addresses creating smaller and more powerful chip
Should library use RFID?
-could be successor technology to bar codes
-considering any introduction into libraries need to ask "why" use new technologies
-manage inventory more effeciently and with less human interaction
-highly advantageous technology for a wide variety of inventory tracking situation
-key factors -library curculation is increasing while library budget and purchasing power are decreasing
RFID and Library Function
-as an identifiers, particularly suited inventory functions and a library has a strong inventory component
-same RFID tag is re-used many times
-can be seen as a security mechanism
-not a highly secured technology
-can read multiple tags at once
-allowing checkouts of a stack of books with single transaction
-tag can be read while book sits on the shelf
-cost of doing inventory goes down
-odd of doing regular inventory goes up
-allowing the library to do more rather than just doing the same functions with greater efficiency
-libraries using RFID still in early ages
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