http://en.wikipedia.org/wiki/Local_Area_Network
Defining characteristics of LAN (in contrast to WAN):
- smaller area;
- not include leased telecommunication lines.
10Base-T & structured cabling: the basis of most commercial LANs.
Wi-Fi: very common, for where copper cabling is not possible, and/or to support easy access for laptops and smartphones.
Fiber-optic cabling: common for links between switches.
Fiber to the desktop: uncommon.
Network topology: describes the layout of interconnections between devices & network segments. (it is the arrangement of the various elements of a computer network)
- Switched Ethernet - the most common LAN topology in use.
- Internet Protocol (TCP/IP) - the standard at the higher layers.
Complex LANs: characterized by their use of redundant links with switches using the spanning tree protocol to prevent loops.
- STP is a network protocol that ensures a loop-free topology for any bridged Ethernet local area network.
Definition: a telecommunications network that allows computers to exchanfge data.
- Data transferred in the form of packets. (network packet: a formatted unit of data carried by a packet-switched network)
- The connections between nodes are established using cable media or wireless media. (network nodes: network computer devices that originate, route, and terminate the data)
- Best-known computer network: the Internet.
- Important feature: providing access to information on shared storage devices.
Twisted pair wire - Coaxial cable - ITU-T G. hn - Optical fiber
Communication protocols: a set of rules for exchanging information over network links.
Internet protocol suite (TCP/IP): the foundation of all modern networking
Routing: the process of selecting network paths to carry network traffic.
Coyle, K. (2005). Management of RFID in libraries. Journal of Academic Librarianship, 31(5), 486-489.
RFID: radio-frequency identification. It is like a barcode but is read with an electro-magnetic field.
It is advanced compared to barcodes in the following aspects:
- does not have to be visible to be read;
- can carry a more complex message;
- the size (smaller and more powerful chips)
There are a lot of very different technologies when talk about RFID, and it is rapidly developed. What varies is: the amount of info the tag carries, the range in which it can be read, the frequency of its radio waves, its physical size, and its cost.
RFID in libraries
It is particularly suited to inventory functions, and the same RFID tag is re-used many times in libraries.
It can be looked as a security mechanism when it is used in anti-theft systems. There are some drawbacks. For example, it can be shielded, it can be easily found and removed. However, libraries should still use it because it is no worse than other security technologies.
It can save libraries' time and money because a single tag serves multiple functions.
It can read multiple tags at once, allowing librarians to check out a stack of books with a single transaction.
By using RFID, the cost of doing an inventory goes down, the odds of actually completing regular inventories goes up.
It can be used to gather statistics on the re-shelving of books in the stacks area.
Problems
With less sturdy items, there may not have a good location for a relatively bulky tag, and that are so numerous that the tag cost is significant.
It also may not be possible to accurately check out a stack of items that are particularly thin.
There are 2 main directions for the RFID at this time. However, libraries need a slightly different technology from either of these. Libraries need tags that are durable, inexpensive, able to be reprogrammed.
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