Flashcards in Chapter 6 Test 2 Deck (80):
What does IEEE 802.3 define?
-traditional wired ethernet.
What is the standard for wireless ethernet?
What are the two reasons for developing a LAN?
-information sharing and resource sharing
Describe Information sharing.
-having users access the same data files, exchange information via email, or use the internet.
What is the benefit of information sharing?
-improved decision making and is generally more important than resource sharing.
Describe resource sharing.
-one computer sharing a hardware device(printer, internet connection) or software package with other computers on the network to save costs.
Describe LAN metering software.
-prohibits using more copies of a package than there are installed licenses.
How much software is used illegally?
-Software Publishers Association(SPA) estimates 40% an annual total of more than $40 billion.
Who has the lowest rate of software piracy?
-North America at 28%.
What are piracy rates for some countries?
-New Zealand 35%
Describe dedicated server networks.
-has one or more computers that are permanently assigned as network servers.
-servers enable users to share files and printers.
Describe dedicated servers.
-can handle large files and databases and uses sophisticated LAN software.
-powerful personal computers.
Describe a server farm.
-when servers are organized into a large set of servers on one part of the network.
-also called a cluster.
Describe OS of a dedicated server.
-usual operating systerm replaced by a network operating system.
-special-purpose network communication software provides the data link layer and network layer protocols that allow data transmission to take place.
What three components must work together and in conjunction with the network hardware to enable communications?
-network operating system in dedicated server
-network communication software on the client
-application software that runs on the server and client computers.
Describe file servers.
-allow many users to share the same set of files on a common, shared disk drive.
Describe print servers.
-handle print request on the LAN.
-help reduce the load on other servers and increase network efficiency.
Describe peer-to-peer netowrks.
-do not require a dedicated server.
-all computers run network software that enables them to function both as clients and as servers.
-often slower than dedicated server networks.
Describe characteristics of peer-to-peer LANs.
-support limited number of computers
-less sophisticated sofware
-prove more difficult to manage.
-cheaper in hardware and software.
-network interface cards
-connects computer to the network cable in a wired network and is one part of the physical layer connection among computers.
-Wireless networks is a radio transmitter that sends and receives messages on a specific radio frequency.
Where is STP used?
-special areas that produce electrical interference such as factories near heavy machinery or hospitals near MRI scanners.
Describe fiber optics.
-thinner and lighter
-weighs less than 10 pounds per thousand feet.
-perfect for BNs, used in Lans.
What frequency ranges does wireless operate at?
-2.4 and 5.0 GHz.
-can transmit 100-150 meters.
-max speed drops fast.
-each channel uses a different part of the 2.4 GHs or 5 GHs frequency range to prefent overlap.
Describe Cat 1>
-UTP, 1 Mbps used by modem
Describe cat 2 cable.
-utp 4 mbps, token ring
Describe cat 3 cable.
-utp, 10 mbps 10BaseT
Describe cat 4 cable
-stp, 16 Mbps, Token ring 16
Describe cat 5 cable
utp, 100 Mbps, 100BaseT
Describe cat 5 cable
sTP, 100 Mbps, 100BaseT
Describe cat 5e
utp, 1 Gbps, 1000Base-T
describe cat 6a
utp, 10 Gbps, 10GBase-T
Describe Cat 7a
STP, 40 Gpos, 10 Gbase T
Fiber, 1000MBS 1000Base
Describe a port.
-each connection point where a cable can be plugged in.
Describe a wireless access point.
-a radio transceiver that plays the same role as a hub or switch in wired Ethernet Lans.
-enables computers near it to communicate with each other
Describe omnidirectional antennas.
-antenna transmits in all directions simultaneously.
-common type is a dipole antenna.
Describe directional antennas.
-projects a signal in one direction.
-signal is stroner and carry further.
Describe network operating system(NOS)
-software that controls the network.
-one part runs on servers and the other part on the clients.
Describe functions of server NOS.
-performs data link, network, and application layer functions.
Describe functions of client NOS.
-functions associated with data link and the network layers.
What is a directory service?
-one of the most important functions of a NOS.
-provide information about resources on the network that are available to the users such as shared printers, shared file servers and application software.
-Active directory service.
Describe Active Direcotry service.
-works much like DNS servers.
-ADS servers are called domain controllers and can act like DNS servers.
What is a forest?
-when you link the hierarchical tree of domains within one organization to other organizations.
What is a domain controller.
-responsible for resolving address information
-manages authorization information.
-ensures resources are available only to authorized users.
What are lightweight directory services?
-standard way for a client to send message to view available resources.
Describe network profiles.
-specifies what resources on each server are available on the network for use by other computers and which devices or people are allowed what access to the network.
-basic geometric layout of the network. and is the way in which the computers on the network are interconnected.
What is a logical topology.
-how network works conceptually.
What is a physical topology?
-how the network is physically installed.
What logical topology is it when we use hubs?
-all computers connected to one half-duplex running the length of the network.
-all computers receive all frames sent on the bus.
Describe switch-based ethernet.
-logical star and physical star.
-manages separate point-to-point circuits.
-circuits are not shared.
What is a forwarding table?
-switch uses to determine which circuit is connected to what computer.
Describe cut-through switching.
-switch begins to transmit the incoming packet on the proper outgoing circuit as soon as it has read the destination address in the frame.
-may forward errors.
-incoming data circuit needs same data rate as outgoing circuit.
Describe store and forward switching.
-receives entire frame before transmitting the outgoing frame.
-data rates can be different
Describe fragment-free switching.
-first 64 bytes of frame are read and stored.
-error checks it.
Describe Media Access Control.
-way to control access to the media.
What MAC control technique does ethernet use?
-wait until circuit is free then transmit.
-If NIC detects any signal other than its own, it assumes collission and sends a jamming signal.
-computers stop transmitting and wait for circuit to become clear.
How far does 1000Base-LX go?
How far does 1000Base-SX go?
Describe wireless ethernet.
-defined by IEEE 802.11
Describe the topologies of Wi-Fi.
-physical star and a logical bus.
What MAC does Wi-Fi use?
-computers listen before they transmit.
How does computers develop an association with an AP?
-active scanning: NIC transmits a probe frame on all active channels.
passive scanning: NIC listens for a beacon frame that is sent out by an access point.
-Distributed coordination function.
-physical carrier sense
-MAC control function that relies on computers to physically listen before they transmit.
-each frame sent using stop-and-wait ARQ
-computers wait longer to transmit than it takes for computer to transmit a ARQ
-point coordination function
-virtual carrier sense.
-overcomes hidden node problem.
-AP controls circuit with a controlled-access technique.
How does PCF work?
-computer sends a request to transmit(RTS) to AP
-AP sends a clear to transmit (CTS) to computer specifing amount of time computer can transmit.
-poorer performance in low-traffic netowrks.
How are wireless frames different from switche ethernet.
-contain a transmitter and receiver address.
-Sequence control field that indicates how a large frame is fragmented.
-eight channels of 54 Mbps
-max range 50 meters
-3 channels of 11 Mbps
-max range 150 meters.
-3 channels of 54 Mbps.
-max range of 150 meters.
-3 channels of 200 Mbps
-max range 150 meters.
-APs can use different frequency ranges
-speeds up to 600 Mbps.
-one old laptop will slow down other laptops.
-backwards compatible with b/g
-a lot of security weaknesses.
-extensible authentication protocol
-allows keys to be produced dynamically.
-WiFi Protected Access(WPA)
-every frame is encrypted using a key and key can be finex in the AP or assigned dynamically with EAP.
-WPA key is longer and harder to break
-key changed for every frame that is transmiteed.
-uses EAP to obtain a master key
-computer and AP negotiate a new key.
Describe MAC address filtering.
-AP only processes frames by computers whose MAC address is allowed.
-special purpose network servers that are optimized to provide extremely fast performance.