-: Cable Review. 2 2
In this lesson, we're going to do a quick review 3 3
of the different specifications, limitations, 4 4
considerations, and applications of network cables. 5 5
First, let's consider the different specifications 6 6
and limitations of our twisted pair copper cables 7 7
in terms of throughput, speed, and distance. 8 8
CAT 5, also known as fast Ethernet or 100BASE-TX, 9 9
operates at 100 megabits per second 10 10
at a distance of up to 100 meters. 11 11
CAT 5e, known as gigabit Ethernet or 1000BASE-T, 12 12
operates at 1,000 megabits per second 13 13
or one gigabit per second at a distance of up to 100 meters. 14 14
CAT 6, also known as 1000BASE-T or 10GBASE-T, 15 15
can operate at 1,000 megabits per second 16 16
or one gigabit per second at a distance up to 100 meters, 17 17
or it can reach speeds of 10 gigabits per second 18 18
at a distance of up to 55 meters. 19 19
CAT 6a and CAT 7 are also known as 10GBASE-T 20 20
and both of these operate at 10 gigabits per second 21 21
at a distance of up to 100 meters. 22 22
Cat 8 is also known as the 40GBASE-T 23 23
and it operates at 40 gigabits per second 24 24
at a distance of up to 30 meters. 25 25
All right, let's consider the different specifications 26 26
and limitations of our coaxial and twinaxial copper cables 27 27
in terms of throughput, speed, and distance. 28 28
Coaxial cables can support speeds 29 29
of up to 100 megabits per second 30 30
at a distance up to 500 meters when using Ethernet. 31 31
Now, coaxial cables can offer us this longer distance 32 32
over a twisted pair cable, 33 33
but they can't reach the higher speeds 34 34
that twisted pair cables can reach in our modern networks. 35 35
Twinaxial cables though can support higher speeds 36 36
of up to 10 gigabits per second, 37 37
but they're limited to a distance 38 38
of only five meters or less. 39 39
Newer twinaxial cables can also increase your speeds 40 40
up to 100 gigabits per second 41 41
at a maximum distance of seven meters. 42 42
But again, these are not mainstream in use yet. 43 43
Next, let's consider the different specifications 44 44
and limitations of our fiber cables 45 45
in terms of throughput, speed, and distance. 46 46
100BASE-FX operates at 100 megabits per second 47 47
at a distance of up to two kilometers 48 48
using multi-mode fiber. 49 49
100BASE-SX is going to operate at 100 megabits per second 50 50
at a distance of up to 300 meters using a multi-mode fiber. 51 51
1000BASE-SX is going to operate at 1,000 megabits per second 52 52
or one gigabit per second 53 53
for a distance of up to 220 meters to 500 meters or more 54 54
using a multi-mode fiber. 55 55
1000BASE-LX is going to operate at 1,000 megabits per second 56 56
or one gigabit per second 57 57
at a distance of up to 550 meters using a multi-mode fiber 58 58
and up to five kilometers 59 59
if we're using a single-mode fiber. 60 60
Now, 10GBASE-SR is going to operate at 10 gigabits per second 61 61
at a distance of up to 400 meters using a multi-mode fiber. 62 62
10GBASE-LR is going to operate at 10 gigabits per second 63 63
at a distance of up to 10 kilometers 64 64
using a single-mode fiber. 65 65
Next, we need to discuss some cable considerations, 66 66
such as shielded versus unshielded 67 67
and plenum versus riser rated. 68 68
First, we have two types of twisted pair cable: 69 69
shielded and unshielded. 70 70
At their core, 71 71
both shielded and unshielded twisted pair cables 72 72
are created the exact same way. 73 73
The only difference is that shielded twisted pair cables 74 74
have each of their individual pairs of wires 75 75
wrapped in a foil shielding. 76 76
This gives them a little bit more protection from EMI. 77 77
Then all four of those wrapped pairs 78 78
are also wrapped with another foil layer 79 79
for some additional protection. 80 80
This extra shielding does help protect 81 81
the shielded twisted pair cables 82 82
from electromagnetic interference 83 83
and power frequency interruptions, 84 84
but it does add cost to it, 85 85
making shielded twisted pair more expensive 86 86
than unshielded twisted pair. 87 87
So you really only use it 88 88
for specific business cases and applications. 89 89
For example, let's say you're running a network 90 90
inside of a radio station or an airport. 91 91
Those areas are a place 92 92
with a lot of electromagnetic interference. 93 93
So you probably want to opt to use shielded twisted pair 94 94
to provide the network 95 95
with a little bit of extra protection. 96 96
Additionally, if you're running a twisted pair network 97 97
inside of a factory with heavy machinery or generators, 98 98
it's also going to be a good idea 99 99
to use shielded twisted pair here 100 100
because there's extra frequencies of EMI 101 101
that are going to be exposed to your cables. 102 102
Now, if you're truly worried 103 103
about electromagnetic interference or EMI though, 104 104
it would actually be a better idea 105 105
to upgrade to a fiber-based network 106 106
because fiber cables are truly immune to EMI 107 107
because they rely on light signals 108 108
instead of electrical impulses to send their data. 109 109
Now, unshielded twisted pair cabling, on the other hand, 110 110
is also used in a lot of our local area networks 111 111
because it's inexpensive, easy to install, lightweight, 112 112
and really flexible. 113 113
Regardless of whether you're going to use 114 114
shielded twisted pair or unshielded twisted pair, 115 115
you need to keep your cable length 116 116
under the maximum recommended length of 100 meters. 117 117
Next, we have to think 118 118
about plenum versus riser rated cables. 119 119
Now, plenum cables are going to be used 120 120
when the cable is going to be run in the spaces 121 121
between the ceiling and the floor above it, 122 122
such as where you put your heating 123 123
and air conditioning duct work. 124 124
Now, these plenum cables have a higher fire rating 125 125
and they're designed with fire retardant plastic jackets 126 126
that use low smoke PVC 127 127
or fluorinated ethanol polymer known as FEP. 128 128
Now usually, plenum rated cables are going to be used 129 129
when you're running cables horizontally in your building 130 130
across a particular level. 131 131
Riser cables, on the other hand, are going to be used 132 132
to run network cables vertically between the floors 133 133
in a building inside a cable riser or an elevator shaft. 134 134
These riser cables are used in non-plenum areas as well. 135 135
These cables are built with special coatings 136 136
that allow them to self-extinguish 137 137
and they prevent the flame from burning through the cable 138 138
and traveling upwards between the floors. 139 139
Now, building codes are specific 140 140
to the location of the building itself, 141 141
and they're going to be determined by your state or county 142 142
that you live in. 143 143
In general, most fire and building codes 144 144
will allow plenum cables to be used 145 145
in both plenum and riser spaces, 146 146
but riser cables can only be used in the risers 147 147
and not in plenum spaces. 148 148
This is because riser cables are not made from PVC or FEP, 149 149
and therefore they can actually release chemicals and smoke 150 150
into the air ducts if they caught fire. 151 151
Finally, let's take a look at some cable applications 152 152
you may come across when working as a network technician. 153 153
These include things like rollover and console cables, 154 154
crossover cables, and Power over Ethernet. 155 155
Now, a rollover or console cable 156 156
is a type of null-modem cable 157 157
that's used to connect a computer terminal 158 158
to a router's console port. 159 159
This cable is typically flat 160 160
and has a light blue color to it 161 161
to help you distinguish it from other networking cables. 162 162
Typically, one side of the cable has an RJ45 connector 163 163
that's used to connect directly to a router's console port. 164 164
The other side of the cable 165 165
traditionally has a DB9 serial connection 166 166
that'll connect to a laptop computer. 167 167
This specialized cable is used to allow the technician 168 168
to directly connect to the router 169 169
and make changes to the configuration 170 170
as a form of outer band communication. 171 171
Now, a crossover cable is a special type of network cable 172 172
that's used to connect two Ethernet devices directly. 173 173
So if you have two computers 174 174
and you don't have a switch or router between them, 175 175
you can use a crossover cable to connect them. 176 176
They're also used to send and receive data 177 177
by enabling complex data transfers 178 178
between two computers, two routers, 179 179
or to other network devices. 180 180
Usually, a crossover cable is created 181 181
by using a TIA-568B pinout on one side of the cable 182 182
and the TIA-568A pinout the other side of the cable. 183 183
If you need to connect a computer to a computer, 184 184
a router to a router, a switch to a switch, 185 185
or a computer to a router, 186 186
then you're going to use a crossover cable. 187 187
Now finally, we have Power over Ethernet. 188 188
Power over Ethernet or PoE 189 189
is a technology that passes electrical power 190 190
over twisted pair Ethernet cables to powered devices. 191 191
Now, this can be done to go to a wireless access point, 192 192
an IP camera or VOIP phone to give them data and power 193 193
on the same cable. 194 194
This enables one cable to give you both data 195 195
and electrical power to these powered devices 196 196
instead of having to have a separate cable for each, 197 197
making it really easy to install things 198 198
like IP security cameras. 199 199
To support Power over Ethernet, 200 200
you need to have at least a Category 5e 201 201
or better copper twisted pair cable. 202 202
Otherwise, it's not going to function right, 203 203
and it could be dangerous. 204 204
Now, Power over Ethernet can provide 15.4-60 watts of power 205 205
using two of the twisted pairs inside of the cable, 206 206
or you can get 60-100 watts of power if you're using 207 207
all four of the twisted pairs inside of a cable. 208 208
Just like other twisted pair cable installations, 209 209
Power over Ethernet can only transmit data and power 210 210
up to the maximum distance of 100 meters. 211 211
All right, I know that was a lot of information 212 212
and I gave it to you really quick, 213 213
but I hope you found this quick review of copper 214 214
and fiber cables and all their different specifications, 215 215
limitations, considerations, and applications 216 216
helpful as you're preparing for your exam.