2. Fundamentals of Ethernet LANs Flashcards
1
Q
A device connected using wireless technology is using Ethernet (true or false)
A
False.
2
Q
Which ethernet standard defines Gigabit ethernet over UTP?
A
1000Base-T
3
Q
Which ethernet standard defines Fast Ethernet over UTP
A
100Base-T
4
Q
Which ethernet standard defines regular ethernet over UTP?
A
10Base-T
5
Q
SOHO stands for?
A
Small Office / Home Office
6
Q
Define LAN
A
Local Area Network
7
Q
Wireless LANs are defined by the IEEE using standards beginning with…
A
802.11
8
Q
Which 3 devices does a typical consumer grade “wireless router” incorporate?
A
A wireless access point, network switch and router.
9
Q
In an example topology each floor of a building has an access switch which leads to a primary switch which could be called a…
A
Distribution Switch
10
Q
Although more expensive, optical cables typically allow for what between nodes?
A
longer cabling distances.
11
Q
What speed is 802.3 ethernet
A
10Mbps
12
Q
The common name for 10Base-T is?
A
Ethernet
13
Q
The common name for 100Base-T is?
A
Fast Ethernet
14
Q
802.3u is the formal standard name for which common ethernet type?
A
Fast Ethernet
15
Q
What speed is fast ethernet
A
100Mbs
16
Q
What is the maximum copper cable length for both Ethernet and Fast Ethernet
A
100m
17
Q
802.3z is the formal name for which type of ethernet
A
Gigabit Ethernet over Fibre (1000Base-LX)
18
Q
802.3ab is the formal name for which type of ethernet?
A
Gigabit Ethernet over Copper (1000Base-T)
19
Q
1000Base-T has a speed of
A
1000Mbps
20
Q
10GBase-T has a speed of
A
10Gbps
21
Q
The common name for 802.3an is?
A
10 Gig Ethernet
22
Q
The maximum distance for 1000Base-Lx is
A
5000m over Fiber
23
Q
The maximum distance for 10GBase-T is
A
100m over Copper
24
Q
10 Gig Ethernet is formally known as
A
802.3an
25
Gigabit Ethernet is formally known as
802.3ab
26
Fast Ethernet is formally known as
802.3z
27
The Ethernet header and trailer are the same regardless of which Ethernet cabling is used? True or False?
True
28
Ethernet data-link protocols focus on sending what?
An ethernet frame from source to destination ethernet nodes.
29
UTP stands for
Unsheilded Twisted Pair
30
An Ethernet LAN typically consists of what?
End devices, switches and different kinds of cabling.
31
The rules defining how two devices send data over a physical link is called...
Encoding Scheme
32
Twisting the pairs of wires in UTP helps to do what?
Reduce EMI (Electromagnetic Interference)
33
The term Ethernet Link refers to what?
Any physical cable between two ethernet nodes.
34
How many pairs of wires are used in 10Base-T and 100Base-T cabling?
2 pairs.
35
How many pairs of wires are used in 1000Base-T ethernet cabling?
4 pairs.
36
NIC stands for?
Network Interface Card
37
The connector for typical copper ethernet cabling is called?
RJ-45
38
SFP+ stands for
Enhanced Small Form-Factor Pluggable
39
SFP stands for
Small Form-Factor Pluggable
40
GBIC stands for
Gigabit Ethernet Interface Converter
41
SFP+ supports speeds of?
10Gbps
42
Why do 10Base-T and 100Base-T use two pairs of wires in a UTP cable?
One pair for each direction.
43
Ethernet NIC transmitters use which pins?
1 and 2
44
Ethernet NIC receivers use which pins?
3 and 6
45
A LAN Switch uses which pins to receive?
1 and 2
46
A LAN Switch uses which pins to transmit?
3 and 6
47
An ethernet switch and NIC should be connected with which type of UTP cable?
Straight-through.
48
When will a straight-through cable work correctly?
When the nodes use opposite pairs for transmitting data.
49
When two devices on an ethernet link both transmit on the same pins which type of UTP cable should be used?
Cross-over
50
Which pins are crossed in a crossover cable?
The transmit pins are crossed over with the receive pins?
51
In a 10Base-T UTP cross over cable, which pins are 1 and 2 connected to?
3 and 6
52
In a 100Base-T UTP straight-through cable which pins are 1 and 2 connected to?
1 and 2
53
When should a cross-over cable be used?
When the endpoints transmit on the same pin pairs.
54
When should a straight-through cable be used?
When the endpoints transmit on different pin pairs.
55
Which devices transmit on pins 1,2
PC NICs, Routers, Wireless Access Points
56
Which devices transmit on pins 3,6
Hubs, Switches
57
Two switches should be connected together using a
Cross over cable.
58
A switch and a router should be connected together using a
Straight-through cable.
59
Auto-mdix is a feature that does what?
Changes a links logic to allow it to work with the wrong cable?
60
Some switches support a feature that allows the wrong cable to be used, this feature is called?
Auto-mdix
61
How does 1000Base-T (Gigabit Ethernet) cabling differ from 10Base-T/100Base-T
It uses four pairs of wires. It uses more advanced electronics that allow both ends to transmit and receive at the same time.
62
A gigabit ethernet crossover cable crossed which pins
1,2 to 3,6 and 4,5 to 7,8
63
What is the common maximum distance for UTP-based Ethernet standards
100m
64
What are the inner layers of a fibre cable called?
Core & Cladding
65
What is the middle layer of a fiber cable called?
Buffer
66
What are the outer two layers of a fiber cabled called?
Strengthener and Outer Jacket
67
Which type of fiber cable allow for the light to enter at many angles?
Multimode Fiber
68
Which type of fiber cable requires the light to enter at a single angle?
Single-mode Fiber
69
Which light source is typically used for single-mode fiber?
Laser
70
Which light source is typically used for multi-mode fiber cable?
LED
71
Which supports greater distances? Multimode fiber or Singlemode Fiber?
Multimode
72
Which mode of fiber is least expensive?
Multimode
73
The standard for 10 Gigabit Ethernet over Multimode Fiber allows for distances up to?
400m
74
The standard for 10 Gigabit Ethernet over Singlemode Fiber allows for distances up to?
10km
75
10GBASE-S has which cable type?
Multimode
76
10GBase-LX4 has which cable type?
Multimode
77
10GBase-LR has a maximum distance of
10km
78
10GBase-E has a maximum distance of
30km
79
10GBase-LX4 has a maximum distance of
300m
80
10GBase-S has a maximum distance of
400m
81
10GBase-E uses which type of cable?
Single-mode
82
10GBase-LR uses which type of cable?
Single-mode
83
In which order of cost would you put UTP, Multimode and Singlemode link types?
UTP Cheapest, Singlemode is the most expensive.
84
UTP cables present a security risk because of which flaw?
EMI could be intercepted.
85
For maximum security which cable type should be used?
Fiber
86
Which 5 components make up the ethernet header?
Preamble, Start Frame Delimiter, Destination, Source, Type
87
Which component makes up the ethernet trailer?
Frame Check Sequence (FCS)
88
How many bytes make up the ethernet frame header preamble?
7 bytes
89
How many bytes make up the ethernet frame header SFD (Start Frame Delimiter)
1 byte
90
How many bytes are used for each of the destination and source mac addresses in the Ethernet frame header?
6 bytes each
91
How many bytes are used in the ethernet header for type
2 bytes
92
What is the minimum and maximum number of bytes between the header and trailer that can contain data within the ethernet frame?
46 and 1500 bytes
93
Define MTU
Maximum Transmission Unit
94
What is the purpose of the Preamble in an Ethernet Frame header?
Synchronization
95
define MAC address
Media Access Control
96
How many bytes is a MAC address?
6 bytes
97
What are other names for a MAC address?
Burned-in-address, ethernet address.
98
A unicast address is
the mac address of a single node or device.
99
Who assigns the unique 3-byte code to manufacturers for use in MAC addresses?
IEEE
100
Define OUI
Organizationally Unique Identifier
101
A MAC address begins with which 3 byte code.
OUI
102
Give two examples of group addresses
Multicast addresses, broadcast address.
103
FFFF.FFFF.FFFF is what?
A broadcast address.
104
What is the ethernet type of IPv4 as used in the Type field of the header
0800
105
What is the ethernet type of IPv6 as used in the Type field of the header?
86DD
106
FCS in the Ethernet Trailer is used for what?
Error Detection
107
FCS stands for
Frame Check Sequence
108
What is the advantage of Full Duplex over Half Duplex
A device does not have to wait before sending, it can send and receive at the same time.
109
Which devices use Half Duplex
Network Hubs
110
What is a disadvantage of half-duplex
If a device is currently receiving a frame it cannot send.
111
Two or more devices at half-duplex transmitting at the same instant would result in what.
A collision
112
A switch operates at Layer 2 - why is this an advantage over a hub?
It understands a frame and can look at the data-link header and trailer. It can transmit to a specific destination.
113
What is the major disadvantage of a network hub?
It repeats a received signal on all ports.
114
What algorithm is used in half-duplex logic to avoid collisions?
CSMA/CD
115
Define CSMA/CD
Carrier Sense Multiple Access with Collision Detection.
116
What happens when a collision occurs with half-duplex logic.
all sending nodes send a jamming signal and then wait a random amount of time.
117
Any link connected to a LAN hub must use what to avoid collisions?
Half-Duplex
118
Ethernet Shared Media refers to what?
Network designs that use hubs and require CSMA/CD and therefore share bandwidth.
119
Ethernet Point-to-Point refers to what?
Network designs that are built with switches and do not require sharing bandwidth.
