Quiz 2 - Ethernet (Ch. 4-5) Flashcards

1
Q

What is a LAN?

A
  • the most relevant definition of a LAN is by link ownership
  • LANs are owned by businesses
  • WAN links are owned by public carriers
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2
Q

Where are LANs in the OSI Model?

A
  • LAN hardware and software are the concern of the bottom two layers
    • Data link
    • Physical
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3
Q

What is the most widely-installed LAN technology?

A
  • Ethernet
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4
Q

What are the Ethernet physical layer standards?

A
  • UTP
  • Fiber Media Standards
  • Ethernet-Specific Signaling Standards
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5
Q

Who is in charge of creating Ethernet signaling standards?

A
  • IEEE 802.3 Working Group
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6
Q

802.3 is synonymous with _____________ ?

A
  • Ethernet
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7
Q

In what year was Ethernet invented?

A
  • 1973
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8
Q

Who designed Ethernet?

A
  • Bob Metcalfe
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9
Q

The Ethernet Frame is made of how many parts?

A
  • 11
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10
Q

The parts of the Ethernet Frame are grouped into what sections?

A
  1. Header
  2. Data Field
  3. Trailer
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11
Q

What parts compose the Header section of the Ethernet Frame?

A
  1. Preamble
  2. Start of Frame Delimiter
  3. Destination MAC Address
  4. Source MAC Address
  5. Tag Protocol ID
  6. Tag Control Information
  7. Length
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12
Q

The Data Field section of the Ethernet Frame is composed of what parts?

A
  1. Logical Control Link (LLC) Subheader
  2. Packet
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13
Q

What parts compose the Trailer section of an Ethernet Frame?

A
  1. PAD
  2. Frame Check Sequence
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14
Q

What parts of the Ethernet Frame make up the Address Fields and what section of the frame are they in?

A
  1. Destination MAC Address
  2. Source MAC Address
  • They are located in the Header
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15
Q

What is the error check field of the Ethernet Frame called?

A
  • Frame Check Sequence
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16
Q

How long is each part of an Ethernet Frame?

A
  1. Preamble = 7 octets
  2. Start of Frame Delimiter = 1 octet
  3. Destination MAC Address = 48 bits
  4. Source MAC Address = 48 bits
  5. Tag Protocol ID = 2 octets
  6. Tag Control Information = 2 octets
  7. Length = 2 octets
  8. LLC Subheader = 7 octets
  9. Packet = variable
  10. PAD = situation-specific
  11. Frame Check Sequence = 4 octets
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17
Q

What topology is traditional Ethernet?

A
  • logical bus
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18
Q

What physical cabling does traditional Ethernet use?

A
  • thick coaxial
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19
Q

How is traditional Ethernet denoted?

A
  • 10Base5
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20
Q

What doe 10Base5 indicate?

A
  1. 10 Mbps
  2. Baseband signaling
  3. 500 meter maximum segment span
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21
Q

What is the maximum number of nodes that traditional Ethernet supports?

A
  • 100
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22
Q

How does traditional Ethernet operate?

A
  • A station transmits a frame with the MAC address of the destination station
  • The frame travels along the bus in both directions
  • Each station reads the frame’s destination address and discards any frame not addressed to it
  • Stations operate independently of each other– with no central controller
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23
Q

Does traditional Ethernet have a central controller?

A
  • No
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24
Q

Does traditional Ethernet avoid collisions?

A
  • No, it detects collisions
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25
Q

What protocol does traditional Ethernet use to handle communication on the bus?

A
  • CSMA/CD
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26
Q

What does CSMA/CD stand for?

A
  • Carrier Sense Multiple Access / Collision Detection
27
Q

What is Carrier Sense?

A
  • Each NIC on the network examines the wire before sending a frame
  • If the node detects traffic, it will back off a random amount of time and try again
28
Q

What is Multiple Access?

A
  • All machines have equal access to the wire
  • Access to the wire is on a first-come, first-served basis
29
Q

What is Collision Detection?

A
  • If two NICs transmit at the same time, a collision results
  • NICs may listen to detect a collision
30
Q

What are the two major ways that traditional Ethernet can be improved?

A
  1. Using a hub
  2. Using UTP cabling
31
Q

How does using a hub with traditional Ethernet affect the network’s topology and operation?

A
  • A hub allows:
    • physical star topology
    • logical bus operation
32
Q

What are the advantages of UTP versus Coax in traditional Ethernet?

A
  • UTP is
    • thinner,
    • lighter, and
    • more flexible than coax
33
Q

What are the advantage of using a hub to improve traditional Ethernet?

A
  • Improved reliability—bus disruptions don’t take down LAN
  • Improved management—simple network management protocol (SNMP) installed on hub
  • Improved maintenance—easier to add workstations
34
Q

What are the main disadvantages of using a hub to improve traditional Ethernet?

A
  • Requires much more cabling
  • Hub becomes single point of failure
35
Q

What is the maximum number of nodes when using 10BaseT?

A
  • 1024
36
Q

What is the most popular topology in use today?

A
  • star
37
Q

How can a hub-based Ethernet network be converted to a switch-based network?

A
  • simply replace the hub with a switch
38
Q

How does using a switch instead of a hub affect network topology and operation?

A
  • A switch uses a
    • physical star topology, but operates as a
    • logical mesh
39
Q

How does a switch transfer traffic to stations on the network?

A
  • a switch connects stations in pairs
40
Q

How are collisions handled with a switch?

A
  • there are no collisions when using a switch
41
Q

What are the advantages of using a switch over a hub?

A
  • Collisions are eliminated
  • Multiple stations can transmit simultaneously—increases throughput
  • Upgrading from a hub-based LAN is simple—simply replace hub with switch
42
Q

How does a switch know how to route network traffic?

A
  • by using a switching table that lists the physical
    • port number (on the switch) and corresponding
    • MAC Address of each station on the network
43
Q

What are the speeds possible with modern Ethernet

A
  • 10 Mbps
  • 100 Mbps
  • 1 Gbps
  • 10 Gbps
44
Q

What speeds of Ethernet may use a hub?

A
  • 10 Mbps
  • 100 Mbps
45
Q

What speeds of Ethernet must use a switch?

A
  • 1 Gbps
  • 10 Gbps
46
Q

What physical cabling does modern Ethernet use?

A
  • UTP
  • fiber-optic
47
Q

What is the maximum number of nodes for modern Ethernet?

A
  • 1024
48
Q

What is the maximum distance for cabling from switch/hub to node for modern Ethernet?

A
  • 100 meters
49
Q

What is the most common speed of Ethernet in use today?

A
  • Gigabit
50
Q

What is the dominant Gigabit standard today?

A
  • 1000BaseT
51
Q

What are the subtypes of 1000BaseX

A
  • 1000BaseCX—twinaxial cable
  • 1000BaseSX—multimode fiber
  • 1000BaseLX—singlemode fiber (laser)
    • Used for long distance transmissions
52
Q

How is 10-Gigabit Ethernet designated?

A
  • 10GBaseX
53
Q

What is LAN segmentation?

A
  • Grouping network stations according to traffic to reduce congestion
  • Each segment becomes a LAN in itself
54
Q

What are the primary criteria for LAN segmentation?

A
  • Segments include workstations that often communicate with…
    • one another
    • a common data source
    • a common resource
55
Q

What is LAN interconnection?

A
  • connecting two LANs in order to share information or resources
56
Q

What hardware device is used to segment or interconnect LANs?

A
  • bridge
57
Q

What is a network bridge used for and at what layer does it operate?

A
  • Used to segment or interconnect LANs
  • Acts as a traffic monitor between two LANs
  • A filter to keep local traffic from crossing between LANs
  • Forwards traffic between segments
  • Operates at Data Link layer of OSI model
58
Q

What is a VLAN?

A
  • Virtual LANs (VLAN) are groups of clients and servers that are
    • allowed to communicate with each other but
    • not with clients or servers on other VLANs
59
Q

What are the main reasons that VLANs are used?

A
  • congestion reduction
  • security
60
Q

How does a VLAN reduce network congestion?

A
  • VLANs reduce traffic when hosts broadcast
  • Broadcasts only go to hosts on the same VLAN
61
Q

How can a VLAN improve network security?

A
  • Clients on one VLAN cannot attack servers on another VLAN
  • An infected host on one VLAN cannot pass virus to a host on another VLAN
62
Q

Can a network client communicate with a server on a different VLAN?

A
  • No, they can only communicate with servers on the same VLAN
63
Q

What hardware is used to divide a LAN into multiple VLANs?

A
  • switch