Week 5 Reading Notes

Wikipedia article - Local Area Network

Local area network (LAN) = computer network that connects in limited area (home, school, lab), with higher rates of data transfer, small geographic area, no need for leased tele lines

• Common current technology: ethernet over twisted pair cabling or wi-fi
  
• Developed in 1970s
• Uses coaxial cables, especially twisted pair (shielded and unshielded), structured cabling, fiber-optic cabling
• Switched ethernet is most common Data Link Layer (at least one switch connected to internet)
  
• Internet Protocol (TCP/IP) is common
• Larger LANs use spanning tree protocol
• Alternatives are metropolitan area network (MAN) or wide area network (WAN)

I had heard of people having "LAN parties" and figured that was a configuration of devices connected to each other, but now I see the appeal of it. If the data transfer rate is high and the participants can keep their activities contained to their group, then that does sound like a good idea.

Wikipedia article - Computer Network

Computer network = collection of hardware/computers connected by communication channels that share resources and information, defined by ability to send/receive data

Public switched telephone network (PSTN) is computer-controlled

Computer network properties:

• facilitate communications
• permit sharing of files/data/info
• share network and computing resources
• may be insecure
• may interfere with other tech
• may be difficult to set up

Wired technologies: twisted pair, coaxial cables, ITU-T G.hn, optical fiber cable

Wireless technologies: terrestrial microwave, communications satellites, cellular and PCS systems, wireless LANs, infrared communication, global area network (GAN)

• Ethernet: connectionless protocols used in LANs
  
• Internet Protocol Suite: TCP/IP - defines the addressing, identification, and routing specification
  
• SONET/SDH: "standardized multiplexing protocols that transfer multiple digital bit streams over optical fiber using lasers"
  
• Asynchronous Transfer Mode: switching technique that encodes data into small, fixed-sized cells
  
• Network programming: computer programs that communicate across a network

• Personal area network (PAN): network close to one person
  
• Local area network (LAN): network in a limited geographic area
  
• Home network: residential LAN
  
• Storage area network (SAN): provides access to consolidated, block level data storage
  
• Campus network: made of interconnection of LANs in a limited geographic area
  
• Backbone network: provides path for exchange of info between LANs or subnetworks
  
• Metropolitan area network (MAN): spans a city or large campus
  
• Wide area network (WAN): covers a large geographic area
  
• Enterprise private network: interconnects various company sites
  
• Virtual private network (VPN): "some of links between nodes are carried by open connections or virtual circuits in some larger network"
  
• Internetwork: connection of multiple networks with routers
  

Common layouts: bus network, star network, ring network, mesh network, fully connected network

Basic hardware components:

• Network interface cards
• Repeaters and hubs
• Bridges
• Switches
• Routers
• Firewalls

Network performance = service quality of tele product from customer perspective

Network security = policies to prevent and monitor unauthorized behaviors relating to network

Network resilience = "ability to provide and maintain acceptable level of service in the face of faults and challenges to normal operation"

I think I understand the basic idea of computer networks, but there's still a lot I don't understand. I know there are different types of networks for different purposes, but I dont think I understand how the networks work exactly or how to set one up exactly.

Management of RFID in Libraries

RFID = Radio Frequency Identifier, computer chip and antenna printed on paper, barcode read with electromagnetic field

Many uses

Benefits:

• amount of info carried
• range in which it can be read
• frequency of radio waves
• small size
• low cost
• can read whole shelf of books without picking up individually
• checkout can read stack of books at once
• increase efficiency of circulation, inventory
• facilitates security, can read if books checked out
• performs many different functions
• greater potential to gather statistics
• possibility to sort items
• more efficiency with self-checkout
  

Downsides:

• privacy issues
• not highly secure, can be blocked by certain materials, can be removed
• cannot help with reshelving part of process
• less human interaction with self-checkout
• may not work with less sturdy or thinner or odd-shaped items
• technology being developed not geared towards library use

Need to consider ROI, user satisfaction

At the library I volunteered at in Minnesota, RFID tags were implemented, and I saw the library grow accustomed to using them. They were good for sorting items as they were returned to the library and for checking in multiple books at a time. I think they might also have helped with security measures, although the alarms seemed to be set off frequently. I didn't notice any problem checking out thin children's books at all.