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224 terms

Networking Flash

STUDY
PLAY
____ are combinations of networking hardware and software that connect two dissimilar kinds of networks.
Correct Answer: Gateways
____ are the distinct units of data that are exchanged between nodes on a network.
Correct Answer: Data packets
____ ARP table entries are created when a client makes an ARP request that cannot be satisfied by data already in the ARP table.
Correct Answer: Dynamic
____ describes a popular serial data transmission method.
Correct Answer: EIA/TIA RS-232 (Recommended Standard 232)
____ describes wiring that connects workstations to the closest telecommunications closet.
Correct Answer: Horizontal wiring
____ hubs possess internal processing capabilities.
Correct Answer: Intelligent
____ is a command-line function for viewing and setting wireless interface parameters and it is common to nearly all versions of Linux and UNIX.
Correct Answer: iwconfig
____ is a method of encrypting TCP/IP transmissions.
Correct Answer: SSL
____ is a most significant problem for wireless communications because the atmosphere is saturated with electromagnetic waves.
Correct Answer: Interference
____ is a public key encryption system that can verify the authenticity of an e-mail sender and encrypt e-mail data in transmission.
Correct Answer: PGP
____ is a set of data or instructions that has been saved to a ROM (read-only memory) chip (which is on the NIC).
Correct Answer: Firmware
____ is a simple Application layer protocol used to synchronize the clocks of computers on a network.
Correct Answer: NTP
____ is a technology used with fiber-optic cable, which enables one fiber-optic connection to carry multiple light signals simultaneously.
Correct Answer: WDM (wavelength division multiplexing)
____ is a terminal emulation protocol used to log on to remote hosts using the TCP/IP protocol suite.
Correct Answer: Telnet
____ is a type of microchip that requires very little energy to operate.
Correct Answer: CMOS
____ is a utility that can verify that TCP/IP is installed, bound to the NIC, configured correctly, and communicating with the network.
Correct Answer: PING
____ is an 802.11n feature that allows two adjacent 20-MHz channels to be combined to make a 40-MHz channel.
Correct Answer: Channel bonding
____ is an 802.11n network feature allowing the combination of multiple frames into one larger frame.
Correct Answer: Frame aggregation
____ is more efficient than TCP for carrying messages that fit within one data packet.
Correct Answer: UDP
____ is one of the most important functions an NOS provides.
Correct Answer: Client support
____ is the preferred communications protocol for remote access communications.
Correct Answer: PPP
____ is the process of reconstructing segmented data.
Correct Answer: Reassembly
____ is the standard for connecting home computers to an ISP via DSL or broadband cable.
Correct Answer: PPPoE
____ memory may be logically carved out of space on the hard drive for temporary use.
Correct Answer: Virtual
____ networks are the most popular type of network for medium- and large-scale organizations.
Correct Answer: Client/server
____ operates at the Network layer and manages multicasting.
Correct Answer: IGMP
____ oversees the IAB (Internet Architecture Board).
Correct Answer: ISOC
____ routing is a technique in which a network administrator programs a router to use specific paths between nodes.
Correct Answer: Static
____ services allow remote users to connect to the network.
Correct Answer: Access
____ services refer to the capability of a server to share data files, applications, and disk storage space.
Correct Answer: File
____ software searches a node for open ports.
Correct Answer: Port scanner
____ virtual computing allows a user on one computer, called the client, to control another computer, called the host or server, across a network connection.
Correct Answer: Remote
1000Base-SX has a maximum throughput of ____.
Correct Answer: 1 Gbps
1000Base-T is a standard for achieving throughputs ____ times faster than Fast Ethernet over copper cable.
Correct Answer: 10
A ____ aggregates multiple DSL subscriber lines and connects them to the carrier's CO.
Correct Answer: DSLAM
A ____ attack occurs when a hacker tries numerous possible character combinations to find the key that will decrypt encrypted data.
Correct Answer: brute force
A ____ attack occurs when a hacker uses programs that try a combination of a user ID and every word in a dictionary to gain access to the network.
Correct Answer: dictionary
A ____ attack occurs when an Internet chat user sends commands to a victim's machine that cause the screen to fill with garbage characters and requires the victim to terminate their chat sessions.
Correct Answer: flashing
A ____ converts digital signals into analog signals for use with ISDN phones and other analog devices.
Correct Answer: terminal adapter
A ____ facilitates communication and resource sharing between other computers on the network.
Correct Answer: server
A ____ firewall is a router (or a computer installed with software that enables it to act as a router) that examines the header of every packet of data it receives to determine whether that type of packet is authorized to continue to its destination.
Correct Answer: packet-filtering
A ____ is a multiport connectivity device that directs data between nodes on a network.
Correct Answer: router
A ____ is a repeater with more than one output port.
Correct Answer: hub
A ____ is a specialized device that allows multiple networks or multiple parts of one network to connect and exchange data.
Correct Answer: connectivity device
A ____ is simply a linked series of devices.
Correct Answer: daisy-chain
A ____ main function is to examine packets and determine where to direct them based on their Network layer addressing information.
Correct Answer: router's
A ____ network connects clients and servers from multiple buildings.
Correct Answer: MAN
A ____ network is confined to a relatively small space.
Correct Answer: LAN
A ____ occurs when two transmissions interfere with each other.
Correct Answer: collision
A class ____ network class is reserved for special purposes.
Correct Answer: D
A common way of sharing resources on a peer-to-peer network is by modifying the ____ controls using the computer's operating system.
Correct Answer: file-sharing
A complex combination of pure topologies is known as a ____ topology.
Correct Answer: hybrid
A digital signal composed of a pulse of positive voltage represents a ____.
Correct Answer: 1
A directional antenna issues wireless signals along a(n) ____ direction.
Correct Answer: single
A directional antenna issues wireless signals along a(n) ____ direction.
Correct Answer: single
A GUID (globally unique identifier) is a 128-bit number that ensures that no two objects have ____ names.
Correct Answer: duplicate
A NIC's transmission characteristics are held in the adapter's ____.
Correct Answer: firmware
A physical topology ____.
Correct Answer: depicts a network in broad scope
A piece of software called ____ translates requests and responses between a client and a server.
Correct Answer: middleware
A program similar to mtr, ____, is available as a command-line utility in Windows XP, Vista, Server 2003, and Server 2008.
Correct Answer: pathping
A PSTN offers ____ security.
Correct Answer: marginal
A router that is not configured to drop packets that match certain suspicious characteristics is an example of a risk associated with ____.
Correct Answer: transmission and hardware
A UDP header contains ____ fields.
Correct Answer: four
A unique characteristic of the 802.11 data frame is its ____ field.
Correct Answer: Sequence Control
A(n) ____ is a list that organizes resources and associates them with their characteristics.
Correct Answer: directory
A(n) ____ is a password-protected and encrypted file that holds an individual's identification information, including a public key.
Correct Answer: digital certificate
A(n) ____ is a pictorial representation of computer functions that, in the case of NOSs, enables administrators to manage files, users, groups, security, printers, and so on.
Correct Answer: GUI
A(n) ____ is a routine of sequential instructions that runs until it has achieved its goal.
Correct Answer: process
A(n) ____ is a self-contained, well-defined task within a process.
Correct Answer: thread
A(n) ____ is the circuit board wire over which a device issues voltage to signal this request.
Correct Answer: interrupt
A(n) ____ is the record of a user that contains all of his properties, including rights to resources, password, name, and so on.
Correct Answer: account
Active Directory organizes multiple domains hierarchically in a domain ____.
Correct Answer: tree
All Ethernet networks, independent of their speed or frame type, use an access method called ____.
Correct Answer: CSMA/CD
An 802.11g antenna has a geographic range of ____ meters.
Correct Answer: 100
An 802.11g antenna has a geographic range of ____ meters.
Correct Answer: 100
An administrator can discover the host name assigned to a client by using the ____ utility.
Correct Answer: hostname
An example of a popular client email software is ____.
Correct Answer: Microsoft Outlook
An example of a popular mail server is ____.
Correct Answer: Microsoft Exchange Server
An NOS that contains a "back door"is an example of a risk associated with ____.
Correct Answer: protocols and software
At the customer's demarcation point, either inside or outside the building, T-carrier wire pairs terminate with a ____.
Correct Answer: smart jack
Because the octets equal to 0 and 255 are ____, only the numbers 1 through 254 can be used for host information in an IPv4 address.
Correct Answer: reserved
Because WAN connections require routers or other Layer 3 devices to connect locations, their links are not capable of carrying ____ protocols.
Correct Answer: nonroutable
Broadband cable requires many subscribers to share the same local line, thus raising concerns about ____ and actual (versus theoretical) throughput.
Correct Answer: security
Collectively, MPLS labels are sometimes called a ____.
Correct Answer: shim
Dependability is a characteristic of ____.
Correct Answer: soft skills
Dial return satellite Internet access is a(n) ____ technology.
Correct Answer: asymmetrical
Each network node has ____ types of addresses.
Correct Answer: two
Each time a computer starts up, the device drivers for all its connected peripherals are loaded into ____.
Correct Answer: RAM
Every UNIX and Linux system contains full documentation of UNIX commands in the ____ pages.
Correct Answer: man
Given their long-distance capabilities, 10GBase-ER and 10GBase-EW are best suited for use on ____.
Correct Answer: WANs
Hardware diagnosis and failure alert are handled by ____.
Correct Answer: management services
If intermittent and difficult-to-diagnose wireless communication errors occur, ____ might be the culprit.
Correct Answer: interference
If intermittent and difficult-to-diagnose wireless communication errors occur, ____ might be the culprit.
Correct Answer: interference
If the standard port number for the Telnet service is 23, a host whose IPv4 address is 10.43.3.87 has a socket address for Telnet of ____.
Correct Answer: 10.43.3.87:23
In ____ , a hacker forges name server records to falsify his host's identity.
Correct Answer: DNS spoofing
In ____ addressing, only Class A, Class B, and Class C addresses are recognized.
Correct Answer: classful
In ____ scanning, the station transmits a special frame, known as a probe, on all available channels within its frequency range.
Correct Answer: active
In ____ wireless systems, the result is a point-to-point link.
Correct Answer: fixed
In ____, a wireless signal splits into secondary waves when it encounters an obstruction.
Correct Answer: diffraction
In ____, both computers verify the credentials of the other.
Correct Answer: mutual authentication
In a ____ attack, a person redirects or captures secure transmissions as they occur.
Correct Answer: man-in-the-middle
In a ____ cable, the usual wire positions are exactly reversed in one of the two RJ-45 terminations.
Correct Answer: rollover
In a process called ____, two 64-Kbps ISDN B channels can be combined to achieve an effective throughput of 128 Kbps.
Correct Answer: bonding
In a ring network, each workstation acts as a(n) ____ for the transmission.
Correct Answer: repeater
In classful addressing, Class C IPv4 address host information is located in the ____.
Correct Answer: last 8 bits
In classful addressing, the Class B IPv4 address network ID is located in the ____.
Correct Answer: first 16 bits
In dotted decimal notation, a(n) ____ separates each decimal.
Correct Answer: period
In IPv4 addressing, a node with an IP address of 168.34.88.29 belongs to a Class ____ network.
Correct Answer: B
In IPv4 addressing, an IP address whose first octet is in the range of 192-223 belongs to a Class ____ network.
Correct Answer: C
In IPv4 addressing, each IP address is a unique ____ number.
Correct Answer: 32-bit
In IPv4 addressing, eight bits have 256 possible combinations.Only the numbers 1 through 254 can be used to identify networks and hosts in an IP address. Explain what the number 0 and the number 255 are used for in IPv4 addressing.
Correct Answer: The number 0 is reserved to act as a placeholder when referring to an entire group of computers on a network - for example, 10.0.0.0 represents all of the devices whose first octet is 10. The number 255 is reserved for broadcast transmissions. For example, sending a message to the address 255.255.255.255 sends a message to all devices connected to your network segment.
In modulation, a simple wave called a ____ wave, is combined with another analog signal to produce a unique signal that gets transmitted from one node to another.
Correct Answer: carrier
In most cases, BOOTP has been surpassed by the more sophisticated IP addressing utility, ____.
Correct Answer: DHCP
In packet switching, when packets reach their destination node, the node ____ them based on their control information.
Correct Answer: reassembles
In the domain name www.google.com, ____ is the top-level domain (TLD).
Correct Answer: com
In the TCP/IP protocol suite, ____ is the core protocol responsible for logical addressing.
Correct Answer: IP
In which OSI model layer do hubs operate?
Correct Answer: Physical
In which OSI model layer does IP operate?
Correct Answer: Network
In which OSI model layer does TCP operate?
Correct Answer: Transport
In which OSI model layer(s) do NICs operate?
Correct Answer: Physical and Data Link
In wireless communication, to exchange information, two antennas must be tuned to the same ____.
Correct Answer: frequency
ISDN PRI uses ____ B channels and one 64-Kbps D channel.
Correct Answer: 23
LEO satellites orbit the Earth with an altitude as low as ____ miles.
Correct Answer: 100
Many network problems can be traced to poor cable ____ techniques.
Correct Answer: installation
Modern LANs use ____ or higher wiring.
Correct Answer: Cat 5
Naming (or addressing) conventions in Active Directory are based on the ____ naming conventions.
Correct Answer: LDAP
Nearly all NICs contain a(n) ____, the device that transmits and receives data signals.
Correct Answer: data transceiver
Often, separate LANs are interconnected and rely on several ____ running many different applications and managing resources other than data.
Correct Answer: servers
On an Ethernet network, a(n) ____ is the portion of a network in which collisions occur if two nodes transmit data at the same time.
Correct Answer: collision domain
On most modern WANs, a ring topology relies on ____ rings to carry data.
Correct Answer: redundant
One of the most common transmission flaws affecting data signals is ____.
Correct Answer: noise
POP3 (Post Office Protocol, version 3) relies on TCP and operates over port ____.
Correct Answer: 110
RADIUS and TACACS belong to a category of protocols known as AAA (____).
Correct Answer: authentication, authorization, and accounting
Satellite Internet access providers typically use frequencies in the C- or ____ bands.
Correct Answer: Ku-
Serial refers to a style of data transmission in which the pulses that represent bits follow one another along a ____ transmission line.
Correct Answer: single
SMTP operates from port ____.
Correct Answer: 25
Solaris employs the file system called ____ for its native file system type.
Correct Answer: UFS
SONET's extraordinary ____ results from its use of a double-ring topology over fiber-optic cable.
Correct Answer: fault tolerance
Standards define the ____ performance of a product or service.
Correct Answer: minimum acceptable
Switches that operate anywhere between Layer 4 and Layer 7 are also known as ____ switches.
Correct Answer: content
TCP is a(n) ____ subprotocol.
Correct Answer: connection-oriented
The ____ gateway is the gateway that first interprets its outbound requests to other subnets, and then interprets its inbound requests from other subnets.
Correct Answer: default
The ____ is a simple set of instructions that enables a computer to initially recognize its hardware.
Correct Answer: BIOS
The ____ is a specialized United Nations agency that provides developing countries with technical expertise and equipment to advance those nations' technological bases.
Correct Answer: ITU
The ____ setting specifies, in hexadecimal notation, which area of memory will act as a channel for moving data between the NIC and the CPU.
Correct Answer: base I/O port
The ____ utility allows you to view a host's routing table.
Correct Answer: route
The 10GBase-T standard is considered a breakthrough for transmitting 10 Gbps over ____ medium.
Correct Answer: twisted pair
The 10-gigabit fiber optic standard with the shortest segment length is ____.
Correct Answer: 10GBase-SR
The average geographic range for an 802.11a antenna is ____ meters.
Correct Answer: 20
The average geographic range for an 802.11a antenna is ____ meters.
Correct Answer: 20
The byte 00001110 means ____ on a digital network.
Correct Answer: 14
The combination of a public key and a private key is known as a ____.
Correct Answer: key pair
The data portion of an Ethernet frame may contain ____ bytes of information.
Correct Answer: 46 to 1500
The data rate of a particular SONET ring is indicated by its ____, a rating that is internationally recognized by networking professionals and standards organizations.
Correct Answer: OC (Optical Carrier) level
The data transmission characteristic most frequently discussed and analyzed by networking professionals is ____.
Correct Answer: throughput
The default subnet mask for a Class B network is ____.
Correct Answer: 255.255.0.0
The distance between corresponding points on a wave's cycle is called its ____.
Correct Answer: wavelength
The Ethernet_II frame type contains a 2-byte ____ field which differentiates it from the older Ethernet_802.3 and Ethernet_802.2 frame types.
Correct Answer: type
The gateways that make up the Internet backbone are called ____ gateways.
Correct Answer: core
The goal of ____ is to establish international technological standards to facilitate the global exchange of information and barrier free trade.
Correct Answer: ISO
The individual geographic locations connected by a WAN are known as ____.
Correct Answer: WAN sites
The more twists per foot in a pair of wires, the more resistant the pair will be to ____.
Correct Answer: cross talk
The most common 1-Gigabit Ethernet standard in use today is ____.
Correct Answer: 1000Base-LX
The most common logical topologies are ____ and ring.
Correct Answer: bus
The most significant factor in choosing a transmission m4ethod is its ____.
Correct Answer: throughput
The phenomenon of offering multiple types of communications services on the same network is known as ____.
Correct Answer: convergence
The points where circuits interconnect with other circuits is known as ____.
Correct Answer: cross-connect facilities
The portion of the PSTN that connects any residence or business to the nearest CO is known as the ____.
Correct Answer: local loop
The primary difference between the two USB standards is ____.
Correct Answer: speed
The printer queue is a ____ representation of the printer's input and output.
Correct Answer: logical
The process of copying directory data to multiple domain controllers is known as ____.
Correct Answer: replication
The process of determining the best path from Point A on one network to Point B on another is known as ____.
Correct Answer: routing
The result from ANDing 11001111 with 10010001 is ____.
Correct Answer: 10000001
The speed of a T-carrier depends on its ____ level.
Correct Answer: signal
The standard message format specified by SMTP allows for lines that contain no more than ____ ASCII characters.
Correct Answer: 1000
The subprotocol that enables TCP/IP to internetwork - that is, to traverse more than one LAN segment and more than one type of network through a router is ____.
Correct Answer: IP
The support and use of multiple processors to handle multiple threads is known as ____.
Correct Answer: multiprocessing
The term ____ memory refers to the RAM chips that are installed on the computer's system board and whose sole function is to provide memory to that machine.
Correct Answer: physical
The use of certificate authorities to associate public keys with certain users is known as ____.
Correct Answer: PKI
To eliminate the possibility of a broadcast storm, switches and bridges implement the ____.
Correct Answer: STP (Spanning Tree Protocol)
Transport layer protocols break large data units into ____.
Correct Answer: segments
UNIX was one of the first operating systems to implement a ____ file system.
Correct Answer: hierarchical
WANs typically send data over ____ available communications networks.
Correct Answer: publicly
What sets ATM apart from Ethernet is its ____ size.
Correct Answer: fixed packet
When signals are free to travel in both directions over a medium simultaneously, the transmission is considered ____.
Correct Answer: full-duplex
When using classful IPv4 addressing, a network ID always ends with an octet of ____.
Correct Answer: 0
Which certification requires candidates to pass lab exams?
Correct Answer: Cisco CCIE
Which connector is used in RS-232 transmissions?
Correct Answer: DB-25
Which Data Link sublayer manages access to the physical medium?
Correct Answer: MAC
Which Data Link sublayer manages flow control?
Correct Answer: LLC
Which IEEE standard describes Ethernet?
Correct Answer: 802.3
Which IEEE standard describes specifications for wireless transmissions?
Correct Answer: 802.11
Which network model ensures that no computer on the network has more authority than another?
Correct Answer: peer-to-peer
Which OSI model layer initiates the flow of information?
Correct Answer: Application
Which OSI model layer manages data encryption?
Correct Answer: Presentation
Which standard is also known as structured cabling?
Correct Answer: TIA/EIA Commercial Building Wiring Standard
Which statement accurately describes the OSI model?
Correct Answer: It describes a theoretical representation of what happens between two nodes communicating on a network.
Which statement describes a certification drawback?
Correct Answer: Certification value may be lessened due to the number of people obtaining them.
Which statement describes an advantage of networks?
Correct Answer: Networks enable multiple users to share resources.
Which term describes the hardware that makes up the enterprise-wide cabling system?
Correct Answer: cable plant
Which term identifies a room containing connectivity for groups of workstations in its area?
Correct Answer: telecommunications closet
Which type of protocol is useful when data must be transferred quickly?
Correct Answer: connectionless
Which type of service supports e-mail?
Correct Answer: communications
Within a classful addressing, ____ is the default subnet mask for a Class C address.
Correct Answer: 255.255.255.0
Within an Ethernet frame, describe what happens if fewer than 46 bytes of data are supplied by the higher layers.
Correct Answer:If fewer than 46 bytes of data are supplied by the higher layers, the source node fills out the data portion with extra bytes until it totals 46 bytes. The extra bytes are known as padding and have no significance other than to fill out the frame. They do not affect the data being transmitted.
Within Ethernet frame types, the ____ signals to the receiving node that data is incoming and indicates when the data flow is about to begin.
Correct Answer: preamble
Without ____, a bus network would suffer from signal bounce.
Correct Answer: terminators
Explain how the distributed backbone is connected. Include a description of its benefits.
Correct Answer: A distributed backbone consists of a number of connectivity devices connected to a series of central connectivity devices, such as hubs, switches, or routers, in a hierarchy. This kind of topology allows for simple expansion and limited capital outlay for growth, because more layers of devices can be added to existing layers.
Explain one way in which BOOTP and RARP are similar. Then describe two ways in which they are different.
Correct Answer: The BOOTP process resembles the way RARP issues IP addresses to clients. The main difference between the two protocols is that RARP requests and responses are not routable. Thus, if you wanted to use RARP to issue IP addresses, you would have to install a separate RARP server for every LAN. BOOTP, on the other hand, can traverse LANs. Also, RARP is only capable of issuing an IP address to a client; BOOTP has the potential to issue additional information, such as the client's subnet mask.
Explain the 5-4-3 rule of networking.
Correct Answer: 10Base-T follows the 5-4-3 rule of networking. This rule says that, between two communicating nodes, the network cannot contain more than five network segments connected by four repeating devices, and no more than three of the segments may be populated (at least two must be unpopulated). The maximum distance that a 10Base-T segment can traverse is 100 meters. To go beyond that distance, Ethernet star segments must be connected by additional hubs or switches to form more complex topologies. This arrangement can connect a maximum of five sequential network segments, for an overall distance between communicating nodes of 500 meters.
Explain the makeup of coaxial cable.
Correct Answer:Coaxial cable consists of a central metal core (often copper) surrounded by an insulator, a braided metal shielding, called braiding or shield, and an outer cover, called the sheath or jacket. The core may be constructed of one solid metal wire or several thin strands of metal wire. The core carries the electromagnetic signal, and the braided metal shielding acts as both a shield against noise and a ground for the signal. The insulator layer usually consists of a plastic material such as PVC (polyvinyl chloride) or Teflon. It protects the core from the metal shielding, because if the two made contact, the wire would short-circuit. The sheath, which protects the cable from physical damage, may be PVC or a more expensive, fire-resistant plastic.
Explain the makeup of fiber-optic cable.
Correct Answer: Fiber-optic cable, or simply fiber, contains one or several glass or plastic fibers at its center, or core. Data is transmitted via pulsing light sent from a laser (in the case of 1- and 10-Gigabit technologies) or an LED (light-emitting diode) through the central fibers. Surrounding the fibers is a layer of glass or plastic called cladding. The cladding has a different density from the glass or plastic in the strands. It reflects light back to the core in patterns that vary depending on the transmission mode. This reflection allows the fiber to bend around corners without diminishing the integrity of the light-based signal. Outside the cladding, a plastic buffer protects the cladding and core. Because the buffer is opaque, it also absorbs any light that might escape. To prevent the cable from stretching, and to protect the inner core further, strands of Kevlar (a polymeric fiber) surround the plastic buffer. Finally, a plastic sheath covers the strands of Kevlar.
Besides an aptitude for logical and analytical thinking, describe additional skills desirable in the networking field.
Correct Answer: Aspiring network professionals also should acquire these skills:• Installing, configuring, and troubleshooting network server software and hardware• Installing, configuring, and troubleshooting network client software and hardware• Understanding the characteristics of different transmission media• Understanding network design• Understanding network protocols• Understanding how users interact with the network• Constructing a network with clients, servers, media, and connectivity devices
Briefly describe IEEE's Project 802.
Correct Answer: IEEE's Project 802 is an effort to standardize physical and logical elements of a network. IEEE developed these standards before the OSI model was standardized by ISO, but IEEE's 802 standards can be applied to the layers of the OSI model.
Briefly describe the IEEE 802.3af standard. Use an analogy and explain why it is useful.
Correct Answer: Recently, IEEE has finalized the 802.3af standard, which specifies a method for supplying electrical power over Ethernet connections, also known as PoE (Power over Ethernet). Although the standard is relatively new, the concept is not. In fact, your home telephone receives power from the telephone company over the lines that enter your residence. This power is necessary for dial tone and ringing. On an Ethernet network, carrying power over signaling connections can be useful for nodes that are far from traditional power receptacles or need a constant, reliable power source.
Briefly explain how CSMA/CD works.
Correct Answer:In CSMA/CD, when a node wants to transmit data it must first access the transmission media and determine whether the channel is free. If the channel is not free, it waits and checks again after a very brief amount of time. If the channel is free, the node transmits its data. Any node can transmit data after it determines that the channel is free.
Define a network operating system (NOS) and describe the tasks it performs.
Correct Answer:An NOS is a special type of software designed to do the following:• Manage data and other resources for a number of clients.• Ensure that only authorized users access the network.• Control which type of files a user can open and read.• Restrict when and from where users can access the network.• Dictate which rules computers will use to communicate.• Supply applications to clients.
Describe a network address including its addressing scheme, formats and alternate names.
Correct Answer:Network addresses follow a hierarchical addressing scheme and can be assigned through operating system software. They are hierarchical because they contain subsets of data that incrementally narrow down the location of a node, just as your home address is hierarchical because it provides a country, state, ZIP code, city, street, house number, and person's name. Network layer address formats differ depending on which Network layer protocol the network uses. Network addresses are also called network layer addresses, logical addresses, or virtual addresses.
Describe four benefits of becoming certified.
Correct Answer: Following are a list of benefits to becoming certified:•Better salary - Professionals with certification can usually ask for higher salaries than those who aren't certified. Employers will also want to retain certified employees, especially if they helped pay for their training, and will offer incentives to keep certified professionals at the company.•Greater opportunities - Certification may qualify you for additional degrees or more advanced technical positions.•Professional respect - After you have proven your skills with a product or system, your colleagues and clients will gain great respect for your ability to solve problems with that system or product. They will therefore feel confident asking you for help.•Access to better support - Many manufacturers reward certified professionals with less expensive, more detailed, and more direct access to their technical support.
Describe how error checking is handled in the Data Link layer.
Correct Answer:Error checking is accomplished by a 4-byte FCS (frame check sequence) field, whose purpose is to ensure that the data at the destination exactly matches the data issued from the source. When the source node transmits the data, it performs an algorithm (or mathematical routine) called a CRC (cyclic redundancy check). CRC takes the values of all of the preceding fields in the frame and generates a unique 4-byte number, the FCS. When the destination node receives the frame, its Data Link layer services unscramble the FCS via the same CRC algorithm and ensure that the frame's fields match their original form. If this comparison fails, the receiving node assumes that the frame has been damaged in transit and requests that the source node retransmit the data.
Describe multicasting.
Correct Answer: Multicasting is a transmission method that allows one node to send data to a defined group of nodes (not necessarily the entire network segment, as is the case in a broadcast transmission). Whereas most data transmission occurs on a point-to-point basis, multicasting is a point-to-multipoint method. Multicasting can be used for teleconferencing or videoconferencing over the Internet, for example.
Describe Physical layer protocol functions when receiving data.
Correct Answer: When receiving data, Physical layer protocols detect and accept signals, which they pass on to the Data Link layer. Physical layer protocols also set the data transmission rate and monitor data error rates. However, even if they recognize an error, they cannot perform error correction. When you install a NIC in your desktop PC and connect it to a cable, you are establishing the foundation that allows the computer to be networked. In other words, you are providing a Physical layer.
Describe the advantage of the star topology.
Correct Answer: Because they include a centralized connection point, star topologies can easily be moved, isolated, or interconnected with other networks; they are, therefore, scalable. For this reason, and because of their fault tolerance, the star topology has become the most popular fundamental layout used in contemporary LANs.
Describe the advantages client/server networks offer over peer-to-peer networks.
Correct Answer: Although client/server networks are typically more complex in their design and maintenance than peer-to-peer networks, they offer many advantages over peer-to-peer networks, such as:• User logon accounts and passwords for anyone on a server-based network can be assigned in one place.• Access to multiple shared resources (such as data files or printers) can be centrally granted to a single user or groups of users.• Problems on the network can be monitored, diagnosed, and often fixed from one location.• Servers are optimized to handle heavy processing loads and dedicated to handling requests from clients, enabling faster response time.• Because of their efficient processing and larger disk storage, servers can connect more than a handful of computers on a network.Together, these advantages make client/server networks easier to manage, more secure, and more powerful than peer-to-peer networks. They are also more scalable - that is, they can be more easily added onto and extended - than peer-to-peer networks.