Ch-6 Networking

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Ch-6 Networking
2014-05-13 18:10:54
Networking Aplus computers topology
Chapter 6 A+ study guide.
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  1. __ were introduced to connect computers in a single office or building.
    Local area networks
  2. __ expanded the LANs to include networks outside the local environment and also to distribute resources across long distances. Generally, it’s safe to think of a __ as multiple, disbursed LANs connected together.
    Wide area networks
  3. __ is a very small-scale network designed around one person. The term generally refers to networks using Bluetooth technology.
    Personal area network
  4. __ is bigger than a LAN but not quite as big as a WAN.
    Metropolitan area network
  5. Technology that uses a WPAN as is its temporary nature; formed on an ad hoc basis. This dynamically created network is called a piconet; devices can communicate with up to seven other devices in one piconet. Two or more piconets can be linked together in a scatternet. In a scatternet, one or more devices would serve as a bridge between the piconets.
  6. __ are a core component of the network, providing a link to the resources necessary to perform any task. The link the __ provides could be to a resource existing on the server itself or a resource on a client computer. The __ is the critical enabler, offering directions to the client computers regarding where to go to get what they need. Servers offer networks the capability of centralizing the control of resources and security, thereby reducing administrative difficulties. They can be used to distribute processes for balancing the load on computers and can thus increase speed and performance. They can also compartmentalize files for improved reliability. That way, if one server goes down, not all of the files are lost.
  7. __ are assigned to provide one or more network services and local access. A __ is expected to be slightly more flexible in its day-to-day use than a dedicated server. __ can be used to direct network traffic and perform administrative actions, but they also often used to serve as a front-end for the administrator to work with other applications or services or perform services for more than one network.
    Non-dedicated Servers
  8. __ are the computers on which the network users do their work, performing activities such as word processing, database design, graphic design, email, and other office or personal tasks. __ are basically everyday computers, except for the fact that they are connected to a network that offers additional resources. __ can range from diskless computer systems to desktops or laptops. Workstations are also known as client computers. As clients, they are allowed to communicate with the servers in the network to use the network’s resources.
  9. A __ is any item that can be used on a network. __ can include a broad range of items, but the following items are among the most important: Printers and other peripherals, Disk storage and file access, Applications.
    Network Resource
  10. Networks use a __ to control the communication with resources and the flow of data across the network. The __ runs on the server. Some of the more popular __ include UNIX and Linux and Microsoft’s Windows Server series.
    Network Operating Systems (NoS)
  11. There are generally two __ models: peer-to-peer and client-server.
    Network Resource Access
  12. In a __ network, the computers act as both service providers and service requestors. __ networks are great for small, simple, inexpensive networks. Windows 7, Vista, XP, 2000, Linux, and Mac OS are popular operating system environments that support a __ resource model. Peer-to-peer networks are also referred to as workgroups.
  13. The __(also known as server-based) model is better than the peer-to-peer model for large networks (say, more than 10 computers) that need a more secure environment and centralized control. __ networks use one or more dedicated, centralized servers. All administrative functions and resource sharing are performed from this point. This makes it easier to share resources, perform backups, and support an almost unlimited number of users. This model also offers better security. However, the server needs more hardware and specialized software (the NOS) to manage the server’s role in the environment.
    Client-Server Resource
  14. Server-based networks are also known as __. The key characteristic of a __ is that security is centrally administered. When you log in to the network, the login request is passed to the server responsible for security, sometimes known as a __ controller.
  15. A __ is a way of laying out the network.
    Network Topology
  16. A __ is the simplest. It consists of a single cable that runs to every workstation. This topology uses the least amount of cabling. Each computer shares the same data and address path. With a __, messages pass through the trunk, and each workstation checks to see if a message is addressed to itself. If the address of the message matches the workstation’s address, the network adapter retrieves it. If not, the message is ignored.
    Bus Topology
  17. A __ branches each network device off a central device called a hub , making it easy to add a new workstation. If a workstation goes down, it does not affect the entire network; if the central device goes down, the entire network goes with it. Because of this, the hub (or switch) is called a single point of failure.
    Star Topology
  18. In a __, each computer connects to two other computers, joining them in a circle and creating a unidirectional path where messages move from workstation to workstation. Each entity participating in the ring reads a message and then regenerates it and hands it to its neighbor on a different network cable.
    Ring Topology
  19. The __ is the most complex in terms of physical design. In this topology, each device is connected to every other device. This topology is rarely found in LANs. If there are x computers, there will be (x ( x – 1)/ 2) cables in the network.
    Mesh Topology
  20. The __ topology is simply a mix of the other topologies. It would be impossible to illustrate it because there are many combinations. In fact, most networks today are not only hybrid but heterogeneous. The __ network may be more expensive than some types of network topologies, but it takes the best features of all the other topologies and exploits them.
    Hybrid Topology
  21. A seven-layer model providing a relationship between the stages of communication, with each layer adding to the layer above or below it. PDNTSPA.
    OSI Model
  22. 7. __ layer Allows access to network services. This is the layer at which file services, print services, and other applications operate.
    Application Layer
  23. 6. __ layer Determines the “look,” or format, of the data. This layer performs protocol conversion and manages data compression, data translation, and encryption. The character set information also is determined at this level. (The character set determines which numbers represent which alphanumeric characters.)
    Presentation Layer
  24. 5. __ layer Allows applications on different computers to establish, maintain, and end a session. A __ is one virtual conversation. For example, all the procedures needed to transfer a single file make up one session. Once the __ is over, a new process begins. This layer enables network procedures, such as identifying passwords, logons, and network monitoring.
    Session Layer
  25. 4. __ layer This layer controls the data flow and troubleshoots any problems with transmitting or receiving datagrams. It also takes large messages and segments them into smaller ones and takes smaller segments and combines them into a single, larger message, depending on which way the traffic is flowing. Finally, the TCP protocol (one of the two options at this layer) has the important job of verifying that all packets were received by the destination host, providing error checking and reliable, end-to-end communications.
    Transport Layer
  26. 3. __ Responsible for logical addressing of messages. At this layer, the data is organized into chunks called packets . The Network layer is something like the traffic cop. It is able to judge the best network path for the data based on network conditions, priority, and other variables. This layer manages traffic through packet switching, routing, and controlling congestion of data.
    Network Layer
  27. 2. __ layer Arranges data into chunks called frames . Included in these chunks is control information indicating the beginning and end of the datastream. This layer is very important because it makes transmission easier and more manageable and allows for error checking within the data frames. The Data Link layer also describes the unique physical address (also known as the MAC address ) for each NIC. The Data Link layer is actually sub-divided into two sections: Media Access Control (MAC) and Logical Link Control (LLC).
    Data Link Layer
  28. 1. __ layer Describes how the data gets transmitted over a physical medium. This layer defines how long each piece of data is and the translation of each into the electrical pulses that are sent over the wires. It decides whether data travels uni-directionally or bi-directionally across the hardware. It also relates electrical, optical, mechanical, and functional interfaces to the cable.
    Physical Layer
  29. Each card must have a unique hardware address, called a MAC address . If two cards on the same network have the same hardware address, neither one will be able to communicate. For this reason, the IEEE has established a standard for hardware addresses and assigns blocks of these addresses to NIC manufacturers, who then hard-wire the addresses into the cards.
    NIC Configuration
  30. __ cable contains a center conductor core made of copper, which is surrounded by a plastic jacket with a braided shield over it. Either Teflon or a plastic coating covers this metal shield.
  31. Common network cables are covered with a plastic called __ (PVC). While __ is flexible, fairly durable, and inexpensive, it has a nasty side effect in that it produces poisonous gas when burned. An alternative is a Teflon-type covering that is frequently referred to as a plenum-rated coating. That simply means that the coating does not produce toxic gas when burned and is rated for use in ventilation plenums that carry breathable air. Plenum rating can apply to all types of network cabling.
    Polyvinyl Chloride
  32. __ is the most popular type of cabling to use because of its flexibility and low cost. It consists of several pairs of wire twisted around each other within an insulated jacket. There are two different types of __: shielded and unshielded. Both types of cable have two or four pairs of twisted wires going through them. The difference is that Shielded has an extra layer of braided foil shielding surrounding the wires to decrease electrical interference. Unshielded has a PVC or plenum coating but no foil shield to protect it from interference.
    Twisted Pair
  33. Twisted-pair cables are unique in today’s network environment in that they use multiple physical wires. Those eight wires need to be in the right places in the RJ-45 connector or it’s very likely that the cable will not work properly. To ensure consistency in the industry, two standards have been developed: 568A and 568B.
    Wiring Standards
  34. __ are used to connect a computer to a computer, hub to hub, switch to switch, hub to switch, or computer directly to a router. The key thing to remember is that a patch (straight-through) cable is the same on both ends. A __ cable is different on each end.
    Crossover cables
  35. __ provides transmission speeds from 100Mbps to 10Gbps and a maximum distance of several miles. Because it uses pulses of light instead of electric voltages to transmit data, it is immune to electrical interference and to wiretapping.
  36. __ cable uses only a single mode of light to propagate through the fiber cable. __ cable is commonly used as backbone cabling. Light travels through single-mode fiber-optic cable using only a single mode. __ cable can transmit up to 10Gbps for up to 40 kilometers, depending on the standard used.
    single-mode fiber
  37. __ allows multiple modes of light to propagate simultaneously. In __ optic cable, the light bounces off the cable walls as it travels through the cable, which causes the signal to weaken more quickly. Multimode fiber is most often used as horizontal cable. Devices that use __ cable typically use LEDs to generate the light that travels through the cable. MMF can transmit up to 10Gbps for up to 550 meters.
    multi-mode fiber
  38. __fiber-optic connector, developed by AT&T, is probably the most widely used fiber-optic connector. It uses a BNC attachment mechanism
    The straight tip (ST)
  39. __ , which was developed by Lucent Technologies. It is a mini form factor (MFF) connector, especially popular for use with Fibre-Channel adapters, fast storage area networks, and Gigabit Ethernet adapters.
    local connector (LC)
  40. __ also sometimes known as a square connector, __ are latched connectors, making it virtually impossible for you to pull out the connector without releasing its latch, usually by pressing a button or release. __s work with either in single-mode or multimode
    Subscriber connector (SC)
  41. A __ is a tool for helping you put connectors on the end of a cable. Many __ will be a combination tool that strips and snips wires as well as crimps the connector on to the end.
  42. __ are very versatile electronic measuring tools. A __ can measure voltage, current, and resistance on a wire.
  43. If you need to trace a wire in a wall from one location to another, a __ is the tool for you; consists of two pieces: a tone generator and a probe. Because it’s so good at tracking, you will sometimes hear this referred to as a “fox and hound.”
    Toner Probe
  44. Use a __ before you install a cable to make sure it works. A decent cable tester will tell you the type of cable
    Cable Tester
  45. A __ is for testing the ability of a network adapter to send and receive. The plug gets plugged into the NIC, and then a loopback test is performed using troubleshooting software. You can then tell if the card is working properly or not.
    Loopback Plug
  46. It’s not a testing tool but one that allows you to connect the exposed ends of a wire into a wiring harnesses, such as a 110 block
    Punch-Down Tool
  47. If you want to connect to a network or the Internet using plain old phone lines and a dial-up connection, a __ is the device you’ll need. __ got their name because they modulate and demodulate digital signals that computers use into analog signals that can be passed over telephone lines. The fastest modems transferred data at 56Kbps.
  48. An __ is any point that allows a user on to a network. The term is commonly used in reference to a wireless __, which lets users connect to your network via an 802.11 technology.
    Access Points
  49. A __ is a device used to link several computers together. __ are very simple devices that possess no real intelligence. They simply repeat any signal that comes in on one port and copy it to the other ports, a process that is also called broadcasting. You’ll sometimes hear them referred to as multiport repeaters. They work at the Physical layer (Layer 1) of the OSI model just as repeaters do.
  50. __connect all ports together electrically but do not have their own power source.
    Passive hubs
  51. __ use electronics to amplify and clean up the signal before it is broadcast to the other ports.
    Active hubs
  52. __ operate in the Data Link layer (Layer 2) of the OSI model. They join similar topologies and are used to divide network segments into multiple collision domains. __isolate network traffic, preventing unwanted traffic from entering a segment when there are no recipients on that segment. __ are more intelligent than repeaters but are unable to move data across multiple networks simultaneously. The main disadvantage of __ is that they forward broadcast packets. Broadcasts are addressed to all computers, so the __ just does its job and forwards the packets. __ also cannot perform intelligent path selection.
  53. __ work at Layer 2 as bridges do, and they provide centralized connectivity just as hubs do. They often look similar to hubs, so it’s easy to confuse them. Hubs pass along all traffic, but __ examine the Layer 2 header of the incoming packet and forward it properly to the right port and only that port. If it helps you to remember their functions, a hub is essentially a multiport repeater, whereas a switch functions like a multiport bridge and, in some cases, a multiport router.
  54. __ are highly intelligent devices that connect multiple network types and determine the best path for sending data. They can route packets across multiple networks and use routing tables to store network addresses to determine the best destination. __ operate at the Network layer (Layer 3) of the OSI model. Because of this, they make their decisions on what to do with traffic based on logical addresses, such as an IP address. __ connect multiple networks to each other, __ do not forward broadcasts. (Switches and bridges break up collision domains, whereas routers break up broadcast domains.) Routers are normally used to connect one LAN to another. Typically, when a WAN is set up, at least two routers are used.
  55. A __ is a specialized computer that acts like a hard drive directly attached to the network. __ devices are dedicated for storage only, and while acting as a file server, they can provide additional services such as data backups as well.
    Network-attached storage (NAS)
  56. A __ is a hardware or software solution that serves as your network’s security guard. __ protect you in two ways. They protect your network resources from hackers, and they can simultaneously prevent computers on your network from accessing undesirable content on the Internet. At a basic level, firewalls filter packets based on rules defined by the network administrator. __ can be stand-alone “black boxes,” software installed on a server or router, or some combination of hardware and software. Most __ will have at least two network connections: one to the Internet, or public side, and one to the internal network, or private side. Some __have a third network this intermediary network is known as a demilitarized zone (DMZ). The basic method of configuring __ is to use an access control list (ACL).
  57. __ is a technology that delivers voice communications over the Internet. A good __ system will allow users to send data, video, and voice all at the same time over the same Internet connection.
    Voice over Internet Protocol (VoIP)