OSI Model

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OSI Model
2010-05-22 12:32:55
Computer Networking

Test your knowledge of the OSI model
Show Answers:

  1. What does the term OSI stand for?
    Open Systems Interconnections
  2. What are the upper layers of the OSI model
    • Application
    • Presentation
    • Session
  3. The OSI reference model divides networking architecture_______ into layers.
  4. List of layers from 1 to 7:
    • 1.~Physical
    • 2.~Data Link
    • 3.~Network
    • 4.~Transport
    • 5.~Session
    • 6.~Presentation
    • 7.~Application
  5. A ___________ __________ is on that does not care if the packet arrives.
    connectionless protocol
  6. A _________-__________ ___________does care about the arrival.
    connection-orientated protocol
  7. The _________model is a reference tool for understanding data communications between any 2 networked systems.
    OSI (Open Systems Interconnection)
  8. Each layer of the OSI model both performs specific functions to support the layers______ it & offers service to the layers ______ it.
    • above
    • below
  9. The 3 lowest layers focus on ______ _______ through the network to an end system.
    passing traffic
  10. The top 4 layers come into play in the _____ _______ to complete the process.
    end system
  11. With the OSI model, networks can be ______ up into manageable pieces.
  12. The OSI model provides a common language to explain ______ & their ________.
    • componets
    • functionality
  13. A networking model offers a generic means to separate computer networking functions into ________ layers.
  14. Each of these layers relies on the layers below it to provide ________ ________ & preforms support to the layers above it.
    supporting capabilities
  15. Such a model of layered functionality is know as a "_____ ______" or "_______ _______".
    protocol stack / protocol suite
  16. ________ are rules, can do their work in either hardware or software, or as w/ most stacks, in a combination of the 2.
  17. The lower layers of the stack do their work in the _______ or _________.
    • hardware
    • firmware
  18. what is firmware?
    software that runs in specific hardware chips
  19. The upper layers of the stack do their work in the?
  20. ISO stands for?
    International Organization for Standards
  21. The main benifit of the OSI model:
    • 1. Helps user understand the big picture of networking
    • 2. Helps users understand how hardware & software elements function together
    • 3. Makes troubleshooting easier by seperating networks into managable peices.
    • 4. Defines terms that networking professionals can use to compare basic functionl relationships on diff networks.
    • 5. Helps users understand new technologies as they are developed
    • 6. Aid in interpreting vendor explanations of product functionality
  22. Control is passed from 1 layer to the next, starting w/ the ________ layer in 1 station, & proceeding to the botton, over the channel to the next station & back up the hierarchy.
  23. TCP/IP is a ______ of protocols.
  24. TCP/IP go together: TCP~ ______ it up & _______ if it arrives,
    IP~ _________ & ________
    • Boxes
    • verifies
    • addresses
    • routes
  25. TCP is a ________ -________; does checking to see if arrival is made
    connection- oriented
  26. IP is _________ just throws on the line.
  27. What is a packet?
    a single unit of data sent from 1 PC to another.
  28. What does a packet contain?
    • source address
    • destination address
    • data
    • error-checking info
  29. A frame consist of?
  30. What does the trailer do? (In a frame)
    verifies the package received & in the right order
  31. What does the header do? (In a frame)
    sends & recieves addresses (IP adderesses)
  32. What does UDP stand for?
    User Datagram Protocol
  33. What type for protocol is UDP?
    Connectionless ** is not commonly used
  34. The Network uses the _____ to deliver a frame?
  35. Errorchecking & control info ensure that a ____ arrives w/out any problems.
  36. Using frames reduces the possibility of lost data or error on the network, b/c each frame has its own ______-_______ _________ checking.
    • built-in
    • error
  37. True or False
    In networking the term "to route" means to intelligently direct data based on addressing, patterns of usage, & availability.
  38. True or False
    Reassembly is the process of reconstructing the segmented data units.
  39. True or False
    The characteristics of the frame components depend on the type of network on which the frame run & on the standards that they must follow.
  40. The Ethernet frame is specified by IEEE _____ standard.
  41. What are the benefits of using a layered network model?
    • it falicilitates trouble shooting
    • it breaks the complex process of networking into more manageable chunks
    • it allows layers developed by different vendors to interoperate
  42. True or False
    Most logical addresses are preset in network interface cards at the factory?
    • False
    • The physical address~ is the MAC address
    • The logical address ~ is the IP address
  43. The OSI Model divides networking architactures into ___ layers.
  44. Why was the OSI model developed?
    Standards were needed to allow any 2 systems to communicate
  45. The ___ model shows how the network functions of a PC should be organized
  46. True or False
    the Internetworking Protocol (IP) is a reliable protocol?
    • ~False~
    • IP is connectionless ~ just worried about addressing & routing
  47. True or False
    Is the IP protocol a connection-oriented protocol?
    • ~False~
    • Connectionless
    • address & routes
    • does not care~throws on the wire
  48. What type of info must a protocol suite supply to be routable?
    MAC address
  49. ______ define a common method of communcation between computers?
  50. True or False
    Every process that occurs during network communications can be associated w/ a layer of the OSI Model?
  51. In the OSI Model, as a data packet moves from tje lower to the upper layers, headers are ____?
  52. What are connectionless protocol (Examples)
    • UDP
    • Ethernet
    • IPX
  53. What application uses the UDP protocol?
  54. What term describes the process of adding headers to data as it moves down the OSI layers?
  55. What makes it easier for different networking vendors to design software & hardware that will interoperate?
    The OSI Model
  56. What protocol maps a logical address (IP) to a MAC (Physical) address?
  57. The most widely used protocol?
  58. A set of "rules" for network transmission?
  59. What must be configured in TCP/IP for 2 PC on the same segement to communicate w/ each other?
    IP address & subnet mask
  60. What is not needed to be configured in TCP/IP for 2 PCs on the same segment to communicate w/ each other?
    Default gateway
  61. The Windows NetBIOS name resolution protocol is called?
  62. What are 2 common classifications for assigning IP addresses?
    Static & Dynamic
  63. What protocol is used to translate IP addresses to MAC addresses?
  64. What is the Physical layer concerned with?
    Signal & Bits
  65. Traditional devices of the Physical layer are?
  66. Physical layer specifications:
    • Electrical
    • mechanical
    • procedural
    • functional
    • move bits between devices
    • specifies voltage, wire speed, & pin-out cables
  67. The Physical layer defines connectors & ______ specifications, as well as the _____ (____) requirements.
    • interface
    • medium (cable)
  68. Electrial, mechanical, & procedural specifications are provided for by sending a ____ ____ on a computer network.
    • bit
    • stream
  69. Physical layer componets include:
    • Cabling system componets
    • Adapter that connect media to the physical interfaces
    • Connector design & pon assignments
    • Hubs, repeaters, & patch panel specifications
    • Wireless system componets
    • Parallel SCSI (Small Computer System Interface)
    • Network Interface Card (NIC)
  70. In a LAN enviroment, ______ __ UPT (Unshieled Twisted Pair) cable is gennerally used for the physical layer for individual device connections.
    Category 5e
  71. ____- ____ cabling is often used for the physical layer in a vertical or riser backbone link.
  72. The ____, ANSI, & other similar standards bodies developed standards for the physical layer.
  73. The physical layer of the OSI model is only part of a ____ (___)
    • LAN
    • Local Area Network
  74. The physical layer defines the ____ or _____ itself.
    • cable
    • medium
    • examples: ThinNet, ThickNet, & Unsheilded Twisted Pairs (UTP)
  75. Physical layer =
    Hardware & Raw Bit Stream
  76. Physical Layer protocols =
    • IEEE 802
    • IEEE 802.2
    • ISO 2110
    • ISDN
  77. Physical layer network componets =
    • Repeaters
    • Multiplexers
    • Hubs (Passive & Active)
    • TDR
    • Oscilloscope
    • Amplifier
  78. physical layer functions:
    • transmit raw bits stream over the physical cable
    • defines cables, card, & physical aspects
    • defines NIC attachments to hardwar, how cable is attached to NIC
    • defines techniques to transfer bit stream to cable
  79. If you incert a Network Interface Card (NIC) but fail to seat it deeply enough in the computers circuit board, your PC will experience network problems at the _____ layer?
  80. Repeaters & hubs operate at which layer?
    Physical layer (Hubs are just hardware)
  81. The Physical layer is concerned w/ the movement of ____ over the physical medium?
  82. what best describes the function of the physical layer?
    defines the electrical & functional specification for the link between end systems.
  83. Data link is concerned with?
    frames & datagrams
  84. data link provides what?
    reliable transit of data across a physical link
  85. traditional devices of the data link layer?
    bridges & switches
  86. true or false
    the data link is divided into 2 sublayers?
    • True
    • LLC & MAC
  87. The sublayers of the Data Link layer are:
    • LLC (Logical Link Control)
    • MAC (Media Access Control)
  88. The LLC sublayer is concerned with: (2)
    • enable upper layers to gain independence
    • allows service access points (SAPs) to interface sublayers to upper-layer function
  89. The MAC sublayer is concerened with:(4)
    • MAC address burned into ROM (24 bit vendor [OUI]/24 bit serial number)
    • Ethernet (CSMA/CD, 802.3, 802.2, EthII)
    • Token Ring (802.5)
  90. Role of Data flow layers (3)
    • Combines bits into bytes & bytes into frames
    • Access to media using MAC address
    • Error detection NOT CORRECTION
  91. Data Link layer functions defines:
    • Physical source & destination address
    • Higher layer protocol (Service Access Point) associated w/ frame
    • Network topology
    • Frame sequencing
    • Flow control
    • Connection-oriened or connectionless
  92. The Data Link layer of the OSI model provides the following functions (4)
    • Allows a device to access the network to send & recieve messages
    • Offers a physical address so a device's data can be sent on the network
    • Works w/ a device's networking software when sending & recieving messages
    • Provides error-detection capabilities
  93. Common networking components the function at (layer 2) the Data Link layer include (3)
    • Network Interface Cards (NICs)
    • Ethernet & Token Ring switches
    • Bridges
  94. NICs have a Data Link address or a ____ address. A switch uses this address to filter & forward traffic, help relive congestion & _____ on a network segement.
    • MAC
    • collision
  95. Bridges & switches function in a similar fashion, however, ________ use application-specific Intergrated Circuits (ASICs) to preform the task in dedicating hardware (which is much faster), while
    __________is normally a software program on a CPU.
    • switches
    • bridging
  96. Data link layer defines the ______ of data on the network.
  97. A network data frame (AKA packet) includes:
    • checksum
    • source address
    • destination address
    • & data
  98. The largest packet that can be sent throug a Data Link layer defines the ______ ______ _____ (___)
    Maximum Transmission Unit (MTU)
  99. The Data Link layer handles the _____ & _____ connections to the packet's destination, using a network interface.
    physical & logical
  100. At the Data Link layer: a host connected to an Ethernet would have an _____ interface to handle connections to the outside world, & a loopback interface to send packes to ____.
    • Ethernet
    • itself
  101. Ethernet addresses a host using a unique, __- bit address called its Ethernet address or ___ ___ ___ (__) address.
    • 48-bit
    • Media Access Control (MAC)
  102. MAC addresses are usually represented as __ colon-separated (:) pair of ___ digits.
    • 2 colon-separated
    • hex digits
  103. 8:0:20:11:ac:85 is an example of what?
    a MAC address
  104. A MAC address is a unique number & is associated w/ a particular Ethernet device, this number comes from the _____.
  105. A host w/ multiple network interfaces should use the same ____ address in each.
  106. The Data Link layer's protocol-specific header specifies the MAC address of the packet's _____ & ___.
    source & destination
  107. When a packet is sent to all hosts (_____), a special MAC address (ff:ff:ff:ff:ff:ff) is used.
  108. Data Link layer =
    Data frames to bits
  109. Data Link layer componets are:
    • Bridges
    • Switch
    • ISDN Router
    • Intelligent Hub
    • NIC
    • Advanced Cable Testers
  110. Data Link Protocols: LLC (and what it is concerned with)
    • LLC = error correction & flow control
    • Manages link control & defines SAPs
    • 802.1 OSI Model
    • 802.2 Logical Link Control
  111. Data Link protocols: MAC sublayer (concerned w/)
    • MAC = communicates w/ the adapter card
    • controls the type of media being used
    • 802.3 CSMA/CD (Ethernet)
    • 802.4 Token Bus (ARCnet)
    • 802.5 Token Ring
    • 802.12 Demand Priority
  112. Data Link functions:
    • turns packets into raw bits & at the reciving end turns bits into packets
    • Handles data frames beween the Network & Physical Layers
    • The reciving end packages raw data from the Physical layer into data frames for delivery to the Network layer
    • Responsible for error-free transfer of frames to another PC via the Physical layer
    • This layer defines the methods used to transmit & recieve data on the network. it consists of the wiring, the devices used to connect the NIC to the wiring, the signaling involved to transmit/recieve data & the ability to detect signaling errors on the network media.
  113. Data Link Layer provides:?
    packets, error-checking & NIC
  114. Data Link layer is concerned w/ (3)
    • Physical addressing
    • Network topology
    • Media access
  115. At the _______ layer, the data blocks are packaged into individual frames.
    Data Link
  116. The IEEE expanded the OSI Model by separating the _____ layer into 2 sublayers, the ___ & ____.
    • Data Link layer
    • LLC (Logical Link Control) & MAC (Media Access Control)
  117. Bits are packaged into frames at this layer?
    Data Link
  118. What are the 2 sublayers of the Data Link Layer?
    LLC (Logical Link Control) & MAC (Media Access Control)
  119. The _____ layer can only detect the error.
    Data Link
  120. The Network layer passes the the data blocks, w/ their addressing identification, to the ____ layer?
    Data Link
  121. What device operates at the Data Link layer of the OSI model?
    A NIC
  122. What protocol map a logical address to a MAC address?