Q&A Hero

Q: In 1994 the Internet Architecture Board issued a report titled "Security in the Internet Architecture" that stated that the general consensus was that the Internet was secure and there were no areas of security concern.

Q: A protocol is concerned with exchanging data between two entities.

Q: Priority could be assigned on a message basis or on a connection basis.

Q: Data are transmitted over an internet in packets from a source system to a destination across a path involving a single network and routers.

Q: Flow control allows routers and receiving stations to limit the rate at which they receive data.

Q: To integrate the IEEE 802.11 architecture with a traditional wired LAN a ________ is used. The logic is implemented in a device, such as a bridge or router, that is part of the wired LAN and that is attached to the DS.

Q: The three MAC frame types are control frames, data frames, and ________ frames.

Q: In the IEEE 802 physical layer frame format the ________ field enables the receiver to acquire an incoming OFDM signal and synchronize the demodulator.

Q: An ________ is an entity that has station functionality and provides access to the distribution system via the wireless medium for associated stations.

Q: The smallest building block of a wireless LAN is a ________ which consists of some number of stations executing the same MAC protocol and competing for access to the same shared wireless medium.

Q: Currently the most popular type of wireless LAN uses ________ techniques.

Q: IEEE ________ embodies changes in three general areas: use of MIMO, enhancements in radio transmission, and MAC enhancements.

Q: Currently wireless LAN products fall into three categories: spread spectrum LANs, OFDM LANs and ________ LANs.

Q: ________ access provides a wireless link between a LAN hub and a mobile data terminal equipped with an antenna, such as a laptop computer or notepad computer.

Q: The IEEE 802.11 ________ layer includes infrared and spread spectrum and covers a range of data rates.

Q: In most cases, spread spectrum LANs operate in the ________ microwave bands so that no Federal Communications Commission licensing is required for their use in the United States.

Q: The IEEE 802.11 services include managing associations, delivering data, and ________.

Q: Within the United States, the FCC has authorized two unlicensed applications within the ISM band: ________ systems and very low power systems.

Q: The ________ module includes either bridge or router functionality to link the wireless LAN to the backbone.

Q: The principal technologies used for wireless LANs are spread spectrum, narrowband microwave, and ________.

Q: The lower sublayer of the MAC layer is the ________ which uses a contention algorithm to provide access to all traffic.A) PCFB) IFSC) DCFD) LLC

Q: The primary service used by stations to exchange MAC frames when the frame must traverse the DS to get from a station in one BSS to a station in another BSS is ________.A) associationB) integrationC) transitionD) distribution

Q: The ________ is a set of one or more interconnected BSSs and integrated LANs that appear as a single BSS to the LLC layer at any station associated with one of these BSSs. A) DS B) AP C) MPDU D) ESS

Q: Three physical media are defined in the original 802.11 standard: DSSS, FHSS, and ________.A) GFSKB) UNNIC) infraredD) Barker sequence

Q: IEEE 802.11 defines three services that provide a wireless LAN with secure access and privacy services: authentication, privacy, and ________.A) deauthenticationB) protected accessC) AP associationD) private access

Q: A ________ is a system used to interconnect a set of basic service sets and integrated LANs to create an extended service set.A) DSB) MPDUC) APD) MSDU

Q: "Recommended practice for the evaluation of 802.11 wireless performance" is the scope of the ________ standard. A) IEEE 802.11,2 B) IEEE 802.11f C) IEEE 802.11r D) IEEE 802.11a

Q: In the United States, ________ microwave bands have been set aside for unlicensed spread spectrum use. A) 2 B) 3 C) 6 D) 4

Q: A number of changes are made in 802.11n in the radio transmission scheme to increase capacity. The most significant of these techniques is ________. A) channel bonding B) diffusion C) interconnection D) spread spectrum

Q: For higher speeds, a technology known as ________ is superior to spread spectrum. A) ODC B) OFDM C) DCIR D) DBIR

Q: A typical coverage area for a wireless LAN has a diameter of ________. A) 50 to 225 m B) 25 to 200 m C) 100 to 300 m D) 75 to 250 m

Q: Employees linking their computers into a temporary network in a conference room for a meeting would be an example of ________ networking. A) Nomadic B) cross building interconnect C) ad hoc D) Lan extension

Q: A wireless LAN linked into a wired LAN on the same premises is referred to as a LAN ________. A) interconnection B) handoff C) ad hoc D) extension

Q: ________ antenna architecture is the most important of the enhancements provided by 802.11n. A) MIMO B) Nomadic C) Directed-beam D) OFDM

Q: The ________ standard defines a set of services and physical layer options for wireless LANs. A) IEEE 802.3 B) IEEE 802.11 C) IEEE 811.2 D) IEEE 802.10

Q: The IEEE 802.11 standards do not include a specification of speed versus distance objectives.

Q: A hub topology, with a MAC algorithm such as CSMA to control, is appropriate for ad-hoc LANs.

Q: A major disadvantage of IEEE 802.11n is that it is not upward compatible with 802.11a or 802.11b.

Q: An individual cell of an IR LAN is limited to a single room because infrared light does not penetrate opaque walls.

Q: Wireless LANs are not as vulnerable to interference and eavesdropping as wired LANs.

Q: Important characteristics of Barker sequences are their robustness against interference and their insensitivity to multipath propagation.

Q: Enabling an employee returning from a trip to transfer data from a personal portable computer to a server in the office is an example of Nomadic access.

Q: A user module acts as an interface to a wireless LAN. .

Q: The popularity of wireless LANs has not grown significantly because the problems of high prices, low data rates, occupational safety concerns, and licensing requirements have not been addressed.

Q: A wireless LAN is defined as one that makes use of a wireless transmission medium.

Q: The most prominent specification for wireless LANs was developed by the IEEE 802.3 working group.

Q: OFDM LANs typically operate in either the 2.4-GHz band or the 5-GHz band.

Q: In a MIMO scheme the transmitter employs just a single antenna.

Q: A wireless LAN must meet the same sort of requirements typical of any LAN, including high capacity, ability to cover short distances,full connectivity among attached stations, and broadcast capability.

Q: The IEEE 802.11 physical layer covers a limited range of data rates.

Q: The IEEE 802.3 standard is known as ________. A) Ethernet B) layer 2 switching C) fibre channel D) subnetworking

Q: Ethernet is now the preferred carrier wire line vehicle for bridging wireless technologies such as WiFi and WiMAX into local Ethernet networks.

Q: IEEE802.3b defines the operation of VLAN bridges and switches.

Q: One of the strengths of the Fast Ethernet approach is that it readily supports a mixture of existing 10-Mbps LANs, 100-Mbps LANs, and newer 16-Gpbs LANs.

Q: With full-duplex operation a station can transmit and receive simultaneously.

Q: Rapid Ethernet refers to a set of specifications developed by the IEEE 802.3 committee to provide a low-cost, Ethernet-compatible LAN operating at 100 Mbps and utilizing 10BASE-T.

Q: With CSMA/CD the amount of wasted capacity is reduced to the time it takes to detect a collision.

Q: A compromise that attempts to reduce collisions, like nonpersistent, and reduce idle time, like 1-persistent, is p-persistent.

Q: The maximum utilization achievable using ALOHA can far exceed that of CSMA.

Q: Ethernet has both a medium access control layer and a physical layer.

Q: Client/server computing has become a dominant architecture in the business environment.

Q: The p-persistent algorithm with binary exponential backoff is efficient over a wide range of loads.

Q: An algorithm is needed with CSMA to specify what a station should do if the medium is found busy.

Q: A disadvantage of Ethernet technology is the lack of availability of reliable and interoperable networking products from vendors.

Q: A variety of signal encoding techniques are used in the various LAN standards to achieve efficiency and to make the high data rates practical.

Q: For 1 Gbps and 10 Gbps operations the CSMA/CD MAC protocol is used.

Q: A ________ is an administratively configured broadcast domain consisting of a subset of end stations attached to a LAN.

Q: An ________ is a direct point-to-point or multipoint communications link, predominantly hardware based and designed for high speed over very short distances. It transfers data between a buffer at the source device and a buffer at the destination device, moving only the user contents from one device to another without regard to the format or meaning of the data.

Q: For shared medium hub operation there are two enhancements to the basic CSMA/CD scheme: carrier extension and ________.

Q: Because it does not transmit a continuous signal between packets, making it useful in battery-powered applications, ________ is designed to produce a 100-Mbps data rate over lower quality Category 3 cable.

Q: The ________ alternative uses unshielded twisted pair in a star shaped topology. The length of a link is limited to 100 meters, unless an optical fiber link is used, then the maximum length is 500 m.

Q: In the 802.3 frame format, a 7-octet pattern of alternating 0s and 1s used by the receiver to establish bit synchronization is the ________.

Q: The IEEE standard restricts the maximum length of coaxial cable to 500 m for 10BASE5 and 200 m for ________.

Q: If the medium is idle, transmit, otherwise, if the medium is busy, continue to listen until the channel is sensed idle, then transmit immediately, are the rules of ________ carrier sense multiple access.

Q: The earliest medium access control technique is known as ________ and was developed for packet radio networks.

Q: The most widely used high speed LANs today are based on ________ and were developed by the IEEE 802.3 standards committee.

Q: IEEE 802.3ba specifies three types of transmission media: copper backplane, twisted pair and ________.

Q: To ensure that backoff maintains stability, IEEE 802.3 and Ethernet use a technique known as ________ backoff.

Q: By assigning the same ________ to end systems on many switches, one or more VLAN broadcast domains can be extended across a large network.

Q: ________ consists of three subfields: user priority, canonical format indicator and VLAN identifier.