NET1 chapter 2
Cat 5 pg.73
Class D, 100MHz. Widely used for fast ethernet and Gigabit networks, also used for telephone and video.
Youre supposed to buy some cat 6 cable to install some new network drops, but the site your buying from list cable by ISO standards. Pg.94
Class E
Cat 6 pg.73
Class E, 250 MHz. Stronger crosstalk specifications than Cat 5e. Popular for new Gigabit ethernet installations and short distance 10 Gigabit networks. Frequently shielded for additional EMI protection, if so the shielding needs a grounded connection.
Which of the following devices would segment the network into multiple collision domains? pg.68
Gateways, Routers, and Switches.
Which of the following devices would segment the network into multiple broadcast domains? pg.68
Gateways, and routers.
APC (Single-mode connector) pg.99
Green
Your fast ethernet card is showing a green light and an amber light. what does it mean? pg.115
It is operating at 100Mbps
1000Base-LX (Long range) pg.110
1 Gbps, 500m on MMF, 5km on SMF ranges.
1000Base-T pg.110
1 Gbps, uses all 8 wires, 100m range
LC (Lucent connector) pg.100
1.25mm round, Snap coupling. A SFF connector. similar in appearance to SC but smaller and with a retaining clip, available in single and duplex forms.
10GBase-LR pg.111
10 Gbps, 10km range
10GBase-SR pg.110
10 Gbps, 33m-400m range
10GBase-T pg.110
10 Gbps, 55m on cat 6, and 100m on cat 6a ranges.
10G pg.108
10 Gigabits or 10000mbps
10base-T (Cat 3) pg.111
10 Mbps, 100m range.
100Base-T (Fast Ethernet) pg.110
100 Mbps, 100m range, Cat 5. Common speed in small networks.
GE (Gigabit) pg.108
1000mbps
Which twisted-pair Ethernet standards require use of all four wire pairs? pg.115
100base-T, and 10Gbase-T
What cable length is supported by most twisted pair ethernet standards? pg.115
100m
FE (Fast ethernet) pg.108
100mbps
Thicknet pg.107
10base5, uses heavy(thick) RG-8 cable.
MTU pg.112
1500 bytes
How many MAC addresses are in an ethernet frame header? pg.57
2
ST (Straight tip) pg.100
2.5mm round, bayonet coupling. One of the first popular MMF connectors but less common for SMF. Increasingly being replaced by Small Form Factor (SMF) connectors.
FC (Ferrule connector) pg.100
2.5mm round, screw coupling. An early single-mode connector using the same ferrule type as ST. Very popular in the past now being replaced by SC, and LC connectors.
How many channels are in a broadband transmission? pg.47
3
Hub pg.59
Layer 1 device that connects multiple nodes into a star configuration. allows device communication.
You need to set up a long distance full duplex connection between two points, but you'd rather not run two cables all that distance. One technology you're evaluating lists FDM as one of its features. Will it do the job with a single cable? pg.57
Maybe, but you need to know more.
Time Domain Reflectometer (TDR) pg.89
Measures signal reflections along the cable to find, breaks, shorts, or minor flaws along its path and to estimate their locations
MMF (multimode fiber) pg.95
More data, short distance.
Wrong termination standard pg.92
One end is T568A, and the Other is T568B. Never intermittent. Solution: remove one end and terminate it correctly. Use the same standard on both ends for optimal output.
OPTICAL Time Domain Reflectometer (OTDR) pg.103
Tests fiber optic cables
Maximum Transmission Unit (MTU) pg.56
The MTU is 1500 bytes, but specialized networks might support non standard jumbo frames with a MTU up to 9000 bytes.
Multiplexing pg.48
The process of combining multiple different messages into unified communications stream.
The data link layer. pg.50
The upper half, the Logical Link Control Sublayer, performs multiplexing tasks using the services provided by the MAC sublayer. In the OSI model, the LLC sublayer is also responsible for error handling and flow control.
Payload pg.56
The useful data that the frame is carrying.
Multilayer switch (Layer 3 switch) pg.67
They filter and forward frames like a switch, but they can also look inside frames like a router to read network layer packets, and forward them between subnets like a router.
You know theres a fault somewhere on that 100m cable, but it looks fine from the outside? pg.94
Time-domain reflectometer.
A layer 2 switch is essentially a bridge with more than two ports pg.68
True
Stranded wires are better for headphones or just things that get moved around alot. pg.
True
Switches are just bridges with ports pg.60
True
T568A, and B give optimal performance. pg.76
True.
What cables use balanced pair signaling? pg.93
Twisted pair
Open pg.92
A break ina connection that should be continuous. Solution: Ensure all cables are firmly connected and replace faulty cable.
Translating Bridge pg.62
A bridge that can talk with multiple different standards.
Tone generator and probe (Fox and Hound) pg.88
A connectivity-testing tool that can be used to trace and identify a wire along its entire length. also known as a toner probe.
Repeater, or extender pg.58
A device made to enable connections over longer distances. (Dumb device)
spectrum analyzer pg.89
A device that measures the amplitude and frequency of a signal in order to examine its waveform characteristics, generally creating output like that of an oscilloscope. (WiFi and Radio frequencies)
Multimeter pg.88
A general purpose electronic tester that can measure resistance, current, or voltage between two points
Multicast MAC address pg.55
A little more complicated than broadcast. If the eighth bit of the address is a 1, it is a multicast address. If its a 0, its unicast. You don't need to look at the bits themselves though: If the second digit of the hexadecimal address is odd (1,3,5,7,9,b,d,f) it's a multicast address. Further details depend on which protocol is being used.
Ferrule pg.98
A rigid cylinder that fits over the end of the cable.
Header pg.56
A six-byte MAC destination address, A six-byte MAC source address
Whats a difference between a switch and a router?
A switch connects devices in a network, a router connects networks.
Full-duplex transmission pg.51
A type of data transmission in which data can move in both directions at the same time. (Twisted pair Ethernet)
Half-duplex transmission pg.51
A type of data transmission in which data can travel in either direction but only in one direction at a time. (Like using a walkie-talkie)
What kind of signaling is generally used by ethernet? pg.57
Baseband
Why is it necessary that each pair of electrical signals on a twisted pair cable corresponds to one physical wire pair? pg.93
Because otherwise it wont produce crosstalk.
Youre setting up a new fiber-optic network using existing fiber that been laid on your campus. You need SFP+ transceivers to plug into it, but you see there are both duplex and bidirectional transceivers available, which should you keep in mind when planning your purchase? pg.105
Bidirectional transceivers require fewer fibers but are more expensive.
UPC (Single-mode connector) pg.99
Blue
While the optical cables in the closet are outwardly identical, some have green connectors, and some have blue. which is UPC, and which is APC? pg.105
Blue is UPC, and green is APC.
Speed or duplex mismatch pg.92
Both ends manually set to an inefficient speed or duplex setting, each end set to different speed or setting, or devices unable to automatically negotiate mutually compatible settings. Solution: fix the device settings, replace the cable, or replace the device.
How does ethernet control multiple accesses? pg.57
CSMA/CI
Attenuation pg.92
Cable is too long, the cable resistance is too high. Solution: Replace with lower resistance cable, use a shorter cable, Segment the cable with repeaters.
Cat 3 pg.73
Class C, 16 MHz. Used in early ethernet; unsuitable for faster networks, but still used for voice telephone cables.
Cat 5e pg.73
Class D, 100 MHz. Category 5 enhanced, same overall properties as Cat 5 but higher testing standards.
You're about to purchase some new network hardware, but you have a couple of old computers you would like to repurpose as network devices to save a little money. what is a useful plan? pg.68
Configure them as routers
Short pg.92
Contact between two wires that should be separate, may be intermittent. Solution: Replace the faulty cable
Frame check sequence pg.56
Done at the layer 2 level
SFP+ pg.102
Enhanced SFP (Newest)
You can use a computer to join two optical inputs to one output, but only if theyre the same wavelength. pg.105
False
STP pg.72
Helps mitigate against EMI
Dirty connector pg.104
Impact: Noise Description/Cause: Connector ends must be kept very clean. Solution: Clean and polish connectors, then reconnect.
Bend radius limitation. pg. 104
Impact: Noise. Description/Cause: Tight bend or kinks can cause temporary or permanent damage. Solution: Straighten tight bends. Replace damaged cables.
Attenuation pg.104
Impact: Noise. Description/cause: Cable too long, or cable flaws decreasing transparency. Solution: Replace cable, use shorter cable, or insert repeaters.
Crosstalk pg.92
Interference between two wire pairs. Near end crosstalk is usually caused by untwisted pairs near the connector. Far end crosstalk is caused further along the cable. Solution: replace the cable, possibly with unshielded U/FTP.
EMI/RMI pg.92
Interference from external electrical radio or electrical sources, can be intermittent depending on those sources. Solution: Isolate the cable from interference by rerouting the cable, moving the source, or adding shielding.
Fiber pg.72
Prevents EMI
QSFP pg.102
Quad small form-factor pluggable. (Newest)
SMF (single-mode fiber) pg.95
Small cord, long distance.
Riser cable, or Riser space pg.71
Still cat cabling, different from plenum. kind do like a bridge between normal and plenum cabling. Generally used in elevator shafts. slows burns in the event of a fire.
What would be reasonable termination methods for a patch cable between a PC and a switch? pg.93
T568A, and B
How are tables cleaned? pg.61
Tables are cleaned by aging. Every table entry has a timer on it. when the timer runs out, usually after 5 minutes the entry is deleted.
Carrier Sense Multiple Access with Collision Detection (CSMA/CD) pg.53
Used by Ethernet
Carrier sense multiple access (CSMA) pg.52
Used by Ethernet and WiFi. When a node needs to send data, it listens to the channels to see if any data is being transmitted - this is called carrier sensing, or carrier detecting. CSMA CAN'T TOTALLY ELIMINATE COLLISIONS.
Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) pg.53
Used by Wi-Fi
T-connector pg.85
Used in Bus topology
Frequency-division multiplexing (FDM) pg.49
Uses different carrier signals operating at different frequencies to transmit different streams. This is the method used by broadband connections. On an optical cable, this method is called wavelength-division multiplexing (WDM), but the principle is the same.
plenum cable pg.71
Uses low-smoke, fire retardant materials, so its safe to run through ventilation systems and other plenum spaces where fire might spread.
Tokens pg.52
When a node receives a token, it sends whatever data it has ready (up to a certain maximum time slot). If it doesn't need to send any, it passes the token out immediately so it doesn't waste resources.
Simplex transmissions pg.51
Where information goes from point A to point B, but never the reverse.
How large are jumbo frames? pg.115
over 1500 bytes.
Baud Rate pg.48
unit of measurement that can be translated into symbols.
