Networking Terms and Notes (ch1-3)

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Networking Terms and Notes (ch1-3)
2012-01-17 19:22:24
Networking ch1 ch2 ch3 CCNA1

Current notes for my networking class. As we go over the other chapters I will add to the notes.
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  1. Data Network
    A digital network used to send data between computers
  2. Network
    1. Collection of computers, printers, routers, switches and other devices that can communicate with each other over some transmission medium.

    2. Command that assigns a NIC-based address to which the router is directly connected.
  3. Internet
    The network that combines enterprise networks, individual users, and ISPs into a single global IP network.
  4. Download
    To transfer data from the computer functioning as a server to the client computer you are using
  5. Instant Messaging
    Real-time communication between two or more people through text.

    Ex: MSN, AIM, YahooMessanger....
  6. Real-time
    Events or signals that show output as fas as possible, or as they happen.
  7. blogs
    Website where entries are made in journal style, created by a user who is in control of the style , visitors may leave comments, aka: weblog.
  8. podcasts
    Digital media file(s) that are distributed over the Internet using syndication feeds, for playback on portable media players and PCs.
  9. wikis
    A website that lets visitors add, edit, and delete content typically anonymously.
  10. collaboration tool
    A tool that helps people communicate & collaborate

    • Examples:
    • Wikidocs, Google Docs, Microsoft Sharepoint....
  11. packet tracer
    A drag-and-drop network simulator developed by Cisco to design, configure, and troubleshoot network equipment within a controlled simulated program environment.
  12. intranet
    A corporate system such as a website that is explicitly used by internal employees. Can be accessed internally or remotely.
  13. extranet
    Part of a company's intranet that is extended to users outside the company (that is, normally over the Internet).
  14. wireless technology
    Allows communication without needing physical connectivity.

    Including cell phones, PDAs, wireless access points, wireless NICs
  15. standards
    An internationally recognized definition of technical specifications that ensure worldwide consistency.
  16. bits
    Binary digit used in the binary numbering system

    Digits are units of information storage and communication in computing.

    Each bit is either a 1 or 0
  17. binary
    A numbering system characterized by 1s & 0s
  18. source
    The origin of the PDU. This can be a process, a host, or a node, depending on the layer to which you are referring.
  19. router
    A network device, typically connected to a range of LAN & WAN interfaces, that forwards packets based on the destination IP addresses.
  20. cloud
    A network device that accesses a service on another computer remotely by accessing the network.
  21. IP
    Internet Protocol

    Network layer protocol in TCP/IP stack for a connectionless internetwork servic. Provides features for Addressing, type-of-service specification, fragmentation, reassembly and security.

    RFC 791
  22. TCP
    Transmission Control Protocol

    Layer 4 protocol of the TCP/IP model

    Lets applications guarantee delivery of data across a network.
  23. convergence
    A form of network that aggregates various forms of traffic such as voice, video and data on eeh same network infrastructure.


    Process by which routers recognize that something has occurred that changes some of the routers routes and reacts to the event to find another best route.
  24. fault tolerance
    The design on networks that can continue to operate without interruption in the case of hardware, software, or communication failures.
  25. redundancy
    A network architecture designed to eliminate network downtime caused by a single point of failure.
  26. scalability
    The ability of a protocol, system, or component to be modified to fit a new need.
  27. internetwork
    A combination of many IP subnets and networks, as created by building a network using routers.

    Used to avoid confusion with the term network since an internetwork can include several IP networks.
  28. packet

    refers to end-user data along with networking headers and trailers that are transmitted through a network.


    Is end-user data, along with network or Internet layer headers and an higher layer headers, but no lower-layer headers or trailers.
  29. QoS
    Quality of Service

    Control mechanism that can provide different priorities to different users of data flows, or guarantee a certain level of performance to a data flow in accordance with requests from the application program.
  30. bandwidth
    Networking measurement of the speed of bits that can be transmitted over a particular link. It is the amount of data that can be transmitted in a certain amount of time. For digital bandwidth, it is usually expressed in bits per second (bps).
  31. priority queuing
    A routing feature in which frames in an interface output queue are prioritized based on various characteristics such as packet size and interface type.
  32. authentication
    A process used to verify the identity of a person or process.
  33. firewall
    Any combination of hardware device and/or software application designed to protect network devices from outside network users and/or malicious applications and files.
  34. single point of failure
    A system or network design characterized by one or more major components that are required to maintain operation.
  35. channel
    A communication path over a medium used to transport information from a sender to a receiver.

    Multiple channels can be multiplexed over a single cable.
  36. segmentation
    TCP process of taking a large chunk of data and breaking it into small-enough pieces to fit within a TCP segment w/o breaking any rules about the max amount of data allowed in each segment.
  37. multiplexing
    Process where multiple digital data streams are combined into one signal.
  38. switch
    Ethernet Layer 2 device

    Requires electrical signal in one port, interprets the bits, and makes a filtering or forwarding decision about the frame.

    • Forwards a regenerated signal.
    • Has many ports (RJ-45)
  39. end device
    A device such as a desktop or mobile device that is used by an end user.
  40. host
    Network device that has an IPv4 address assigned to it to communicate over a network.
  41. client
    A network device that accesses a service on another computer remotely by accessing the network
  42. host address
    IPv4 address of a network host - Network Layer Address
  43. intermediary device
    Device that connects end devices to the network or interconnects different networks.

    Ex: Routers
  44. physical address
    Data link layer address

    Ex: MAC address.
  45. encoding
    To change energy levels transmitted over some networking medium to transmit bits over that medium.
  46. LAN
    Local-Area Network

    Network created for devices located in a limited geographic area, through which the company owning the LAN has the right to run cables.
  47. ISP
    Internet Service Provider

    Company that helps create the internet by providing connectivity to enterprises and individuals,

    as well as interconnecting to other ISPs to create connectivity to all other ISPs.
  48. protocols
    Written specification that defines what tasks a service or device should perform.

    Defines messages (headers), rules, process by which the messages are used to achieve some stated purpose.
  49. protocol suite
    Delineation of networking protocols and standards into different categories, called layers, along with definitions of which sets of standards and protocols need to be implemented to create products that can be used to create a working network.
  50. IEEE
    Institute of Electrical and Electronics Engineers

    International, nonprofit organization for the advancement of technology related to electricity.

    Maintains standards defining many LAN protocols.
  51. IETF
    Internet Engineering Task Force

    Standards body responsible for the development and approval of TCP/IP standards.
  52. layered models
    Model that consists of various layers that enable the development and explanation of technology to be done on a modular basis.

    Allows interoperability among different technologies among the different layers.
  53. TCP/IP
    Transmission Control Protocol/Internet Protocol

    Network model defined by the IETF that has been implemented on most computers and network devices in the world.
  54. encapsulation
    Process in which a device adds networking headers and trailers to data from an application for the eventual transmission of the data over the medium.
  55. decapsulation
    Process in which the end-device receives data from a transmission and examines the headers and trailers at each stack layer

    aka de-encapsulation
  56. PDU
    Protocol Data Unit

    Generic term from OSI that refers to the data, headers, and trailers about which a particular networking layer is concerned.
  57. segment
    1. Collision domain that is a section of a LAN that is bound by bridges, routers, or switches.

    2. LAN w/ bus topology it is a continuous electrical circuit that is often connected w/ repeaters.

    3. W/ TCP it serves as a verb referring to the work TCP does to accept a large piece of data from an end device breaking it into smaller pieces. OR as a noun it refers to one of those smaller pieces of data.
  58. frame
    Layer 2 PDU that has been encoded by a data link layer protocol for digital transmission.

    • Ex:
    • Ethernet frames
    • PPP frames
  59. OSI
    Open System Interconnection

    International standardization program created by ISO and ITU-T to develop standards for data networking that facilitate multivendor equipment interoperability.
  60. ISO
    International Organization for Standardization

    International standards body that defines many networking standards. Also, the standards body that created the OSI model.
  61. port
    multiple meanings in networking

    On a Ethernet hub, switch = interface (physical connector in the device you plug the cable into)
  62. data
    Application layer protocol data unit.
  63. source device
    The device that is originating the PDU.
  64. DNS
    Domain Name System

    Internet-wide system by which hierarchical set of DNS servers collectively hold all the name-IP address mappings, with DNS servers referring users tot he correct DNS server to successfully resolve a DNS name.
  65. RFC
    Requests for Comments

    Series of documents and memoranda encompassing new research, innovations, and methodologies applicable to Internet technologies.

    Reference for how technologies should work.
  66. syntax
    The structure and order of words in a computer language.
  67. session
    A related set of communications transactions between two or more network devices.
  68. client
    Network device that accesses a service on another computer remotely by accessing the network.
  69. server
    Can refer to computer hardware that is to be used by multiple concurrent users.

    Can refer to computer software that provides services to many users.

    Example: consists of web server software running on some computer.
  70. daemon
    Computer program that runs in the background and is usually initiated as a process.

    Ofter support server processes.
  71. peer
    A host or node that participates in some form of a group.

    Peers that participate jointly in the same activity, each having a server and client component.
  72. scheme
    A plan, design, or program of action to be followed.

    Sometimes an addressing plan is called an addressing scheme.
  73. IP Address
    32-bit number written in dotted decimal notation, used by the IP to uniquely identify an interface connected to an IP network.

    Also used as a destination address in an IP header to allow routing.

    Or as a source address to allow a computer to receive a packet and to know which IP address to send a response to.
  74. domain name
    Name defined by DNS that uniquely identifies a computer in the Internet.

    Corresponds with the IP address

    ex: ip address
  75. network address
    A dotted decimal number defined by the IPv4 protocol to represent a network or subnet.

    REpresents the network that hosts reside in.

    AKA a network number or network ID
  76. resource record
    DNS data records.

    Precise format is defined in RFC 1035.

    Important fields: name, class, type, and data.
  77. DNS resolver
    Client end of the DNS client-server mechanism.

    Creates queries sent across a network to name a server, interprets responses, and returns information to the requesting programs.
  78. nslookup
    A part of a computer network that every device communicates with using the same physical medium.

    Can be extended by hubs or repeaters.
  79. query
    A request for information.

    Queries are answered with replies.
  80. cache
    Temporary storage where data that has been retrieved or calculated and is accessed frequently can be stored.

    Reduces the average access time and reduces the overhead of recalculating the data.
  81. authoritative
    A source of information that is highly reliable and known for its accuracy.
  82. plug-in
    In a web browser, an application the browser uses, inside the browser window, to display some types of content.

    Ex: typically uses a plug-in to display video.
  83. HTTP
    Hypertext Transfer Protocol

    Defines the commands, headers, and processes by which web servers and web browsers transfer files.
  84. distributed
    Method of computer processing in which different parts of a program run simultaneously on two or more computers that are communicating with each other over a network.
  85. collaborative
    Information systems that allow the creation of a document(s) that can be edited by more than one person in real time.
  86. encryption
    Process of obscuring information to make it unreadable.

    Applies mathematical formula to the data along with a secret number (encryption key) resulting in an encrypted data packet and is sent through the network.
  87. POP
    Post Office Protocol

    A protocol that allows a computer to retrieve e-mail from a server.
  88. SMTP
    Simple Mail Transfer Protocol

    Application protocol typically not used by an end user.

    Used by the network management software and networking devices to allow a network engineer to monitor and trouble shoot network problems.
  89. MUA
    Mail User Agent Program

    Used to download and send e-mail.

    • Use POP3 to receive e-mails
    • Use SMTP to send e-mails
  90. spam
    Unsolicited commercial e-mail.
  91. gateway
    Relatively general term referring to different kinds of networking devices.

    {Routers were once galled gateways}
  92. DHCP
    Dynamic Host Configuration Protocol

    Used to dynamically assign IP config's to hosts.

    Services defined by the protocol are used to request & assign IP addresses, default gateway, and DNS server address to a network host.
  93. subnet mask
    A dotted decimal number that helps identify the structure of IP addresses.

    Mask represents the network and subnet parts of related IP addresses with binary 1s and the host part of related IP addresses with 0s.
  94. broadcast
    A form of transmission where one device transmits to all devices within the network or on another network.
  95. SMB
    Server Message Block

    An application level network protocol mainly applied to shared access to files, printers, serial ports, and miscellaneous communications between nodes on a network.
  96. UNIX
    A multiuser, multitasking operating system (196/70s)

    AT&T employees developed
  97. IAC
    Interpret as Command

    In Telnet application, commands are always interfaced by a character with the decimal code 255, known as an IAC character
  98. flow control
    The management of data flow between devices in a network.

    Used to avoid to much data arriving before a device can handle it, causing data overflow.
  99. control data
    Data that directs a process. A flag in a data-link frame is an example of control data.
  100. IANA
    Internet Assigned Numbers Authority

    An organization that assigns the numbers important to the proper operation of the TCP/IP protocol and the Internet, including assigning globally unique IP addresses.
  101. well-known ports
    • Used by TCP and UDP, with values between 0 - 1023
    • these ports are allocated by high-privilege processes.

    Used so that all clients know the correct port number to connect to.
  102. registered ports
    • Using values between 1024 - 49,151
    • these numbers are equivalent to well-known ports in concept,

    but they are specifically used for non-privileged application processes.
  103. dynamic or private ports
    TCP & UDP ports that range from 49152 - 65535 and are not used by any defined server applications.
  104. URG
    a 1-bit flag in the TCP header used to indicate that the receiving host should notify the destination process to do urgent processing.
  105. ACK
    a 1-bit flag in the TCP header that indicates that acknowledgment field is valid.
  106. PSH
    a 1-bit flag in the TCP header that is used to request to the higher layers for immediate delivery of the packet.
  107. RST
    a 1-bit flag in the TCP header that is used to request that a connection be re-established.
  108. SYN
    a 1-bit flag in the TCP header used to indicate the initial value of the sequence number.

    Flag is only set in the first two segments of the three-way TCP connection establishment sequence.
  109. FIN
    a 1-bit field in the TCP header that is used by a device that wants to terminate its session with the other device.

    This done by inserting the FIN flag in the flag field found in the TCP segment.
  110. Which form of communication is a real-time text-based communication type used between two or more people who mostly tect to communicate with each other?

    a. Weblogs
    b. Wikis
    c. Instant Messaging
    d. Podcasting
    e. Collaboration Tools
    c. Instant Messaging
  111. Which type of network provides customer's limited acess to corporate data such as inventory, parts lists and orders?

    a. Intranet
    b. extranet
    c. Internetwork
    d. Internet
    b. Extranet
  112. What balances the importance of traffic and its characteristics in order to manage data?

    a. Network Administration
    b. Network Traffic
    c. QoS Strategy
    d. Network Evaluation
    c. QoS Strategy
  113. Which processes occur to network traffic so that quality of service stratefies work correctly? (choose two)

    -Traffic is classified based on QoS requirements.
    -Priorities are assigned to each classification of application data.
    -Web traffic is always assigned to the high priority queue for processing.
    -Digital movies are always assigned to the high priority queue for processing.
    -E-mail traffic is always assigned to the low priotity queue
    • Traffic is classified based on QoS requirements.
    • Priorities are assigned to each classification of application data.
  114. What are two compenents of network architecture? (choose two)

    -People that comprise the human network
    -Programmed services and protocols that moce the messages across the network
    -Data transferred across the network
    -Technologies that support network communications
    -Corporations that operate and maintain the data network
    • Programmed services and protocols that more the messages across the network
    • Technologies that support network communications
  115. For which three reasons where circuit-switched, connection-oriented technologies rejected when the Internet was being developed? (Choose 3)

    -Circuit-switched technologies required that a single message be broken up into multiple message blocks that contain addressing information.
    -Early circuit-switched networks didi not automatically establish alternative circuits in the event of circuit failure.
    -Circuit-switched technologies required that an open circuit between network endpoints be establushed, even if data was not actively being transferred between locations.
    -The quality and consistency of messages transmitted across a connection-oriented, circuit-switched network could not be guaranteed.
    -The establishment of multiple, simultaneous open circuits for fault tolerance was costly.
    • Early circuit-switched networks didi not automatically establish alternative circuits in the event of circuit failure.
    • Circuit-switched technologies required that an open circuit between network endpoints be establushed, even if data was not actively being transferred between locations.
    • The establishment of multiple, simultaneous open circuits for fault tolerance was costly.
  116. For which three reasons was a packet-switched connectionless data communications technology used when developing the Internet (choose 3)

    -It can rapidly adapt to the loss of data transmission facilities.
    -If efficiantly utilizes the network infrastructure to transfer data.
    -Data packets can travel multiple paths through the network simultaneously.
    -It allows for billing of network use by the amount of time a connection is established.
    -It required that a data circuit between the source and destination be established before the data can be transferred.
    • It can rapidly adapt to the loss of data transmission facilities.
    • If efficiantly utilizes the network infrastructure to transfer data.
    • Data packets can travel multiple paths through the network simultaneously.
  117. What is the role of the QoS in a converged network?

    a. Ensures that all traffic above available bandwidth levels is dropped
    b. Establishes delivery priorities for different communication types in a network
    c. Determines precise priorities for all network communication
    d. Allows unused bandwidth to be shares by other organizations within the network
    b. Establishes delivery priorities for different communication types in a network
  118. _____ are collaborative web pages created and edited by users.
  119. Rules that govern the process of network communicarion are called _____.
  120. Copper cables and fiber-optic cables are two types of network _____.
  121. What are two components of network architecture?
    • Biult-in growth potential
    • Redundant technologies