-: Transceivers. 2 2
So at this point we've already discussed copper cables 3 3
and fiber optic cables, 4 4
but what's really the difference between these two 5 5
and when should use each one? 6 6
Well, when we compare copper versus fiber optic, 7 7
we really need to compare it in four main areas, 8 8
the speed of the bandwidth, the distance it can cover, 9 9
how good it is against EMI 10 10
and what kind of security it can give you. 11 11
Now, when we deal with fiber optic cabling, 12 12
it has a lot of advantages. 13 13
It has a higher bandwidth than copper. 14 14
It can cover a much larger distances than copper, 15 15
it's immune to EMI because it's not using electricity 16 16
and instead is using light to pass the data. 17 17
And also it has better security because it's much harder 18 18
to tap into and to be able to read those signals 19 19
without using extremely expensive equipment. 20 20
So for all these reasons, fiber is really great, 21 21
but copper has a couple of benefits too. 22 22
Copper cabling is less expensive. 23 23
It's really easy to install, 24 24
and the tools to work with it are really really inexpensive 25 25
and really cheap. 26 26
In fact, you can go on Amazon and get 100 RJ-45 connectors, 27 27
a crimper and a tester 28 28
for all less than about $10 in America. 29 29
If you try to do the same thing for fiber optic cabling, 30 30
it'll cost you several 100 dollars to get the pieces 31 31
to build your own cable. 32 32
So when you look at fiber versus copper cabling, 33 33
I want you to remember that fiber is used 34 34
when you need to cover a really long distance. 35 35
Remember fiber optic cables can go up to 40 kilometers 36 36
or more, and they carry much higher speeds 37 37
than copper cables. 38 38
Fiber optic cabling can even reach speeds 39 39
of 60 to 70 terabytes or more. 40 40
It can be extremely fast. 41 41
Copper on the other hand can go relatively short distances. 42 42
If you're dealing with CAT 3 through CAT 7 cables, 43 43
you'll remember we can't go higher than a 100 meters 44 44
without losing our signal. 45 45
Copper cabling is also much slower. 46 46
Today it's common to find speeds up to 10 gigabits 47 47
per second, and distance is limited to a 100 meters, 48 48
if you're using a CAT 7 cable. 49 49
Now, if you use the newest cable CAT 8, 50 50
you can reach speeds of 25 to 40 gigabits per second, 51 51
but you can only go 30 meters before the signal starts 52 52
deteriorating and you start losing it 53 53
due to single attenuation. 54 54
This way, your connection will start slowing or failing. 55 55
Now 10 gigabits per second is pretty fast over copper, 56 56
if we want to stick with CAT 7 cabling, 57 57
and this is pretty fast for most home and office networks 58 58
that you might be using. 59 59
But if you're going to be using a long-haul circuit, 60 60
or you need something faster than 10 gigabits per second, 61 61
you definitely want to consider using fiber, 62 62
because its benefits are going to outweigh 63 63
the limitations of copper cabling. 64 64
So as you can see, 65 65
sometimes you're going to want to use copper, 66 66
and sometimes you're going to want to use fiber. 67 67
If you're dealing with your local area network, 68 68
you're probably going to be using copper. 69 69
You start dealing with a man or a win, 70 70
you might be moving up to fiber. 71 71
So let's say I decide to use a fiber cable to cover 72 72
a 30 mile distance, going across the city 73 73
between two office buildings. 74 74
That is considered my long-haul circuit 75 75
or a Wing Connection for this particular network. 76 76
Now, once that fiber reaches my building across town, 77 77
I need to connect my network to it. 78 78
But if it's like most office networks, 79 79
it's going to be made up of copper cabling 80 80
and all the switches are going to support copper cables 81 81
like CAT 6 or CAT 7 as well. 82 82
So now that the fiber has gotten to my building, 83 83
how can I transfer that fiber back into my copper network 84 84
so I can operate with the rest of my lane? 85 85
Well, that's the idea of where media converters 86 86
come into play. 87 87
A media converter or a transceiver is used to convert media 88 88
from one format to another, like going fiber to copper 89 89
or copper to fiber. 90 90
These are considered a layer one device because all they do 91 91
is take a signal in convert it and repeat it 92 92
out the other side. 93 93
For example, if I have a media converter 94 94
that takes in a fiber connection, 95 95
like an ST connector stick and twist, 96 96
I can then take that in transmit that fiber 97 97
to this transceiver, and then I can convert it 98 98
and send it out the other side as an RJ 45 connector. 99 99
That way I can then connect it to a CAT 5, 100 100
six or seven cable and go into a switch. 101 101
This is the idea of using a media converter or transceiver. 102 102
Essentially we can take input from fiber 103 103
and send the output to copper. 104 104
And we'll receive information from the copper 105 105
side of the network, we can convert it and send it back out 106 106
the fiber side too. 107 107
Basically media converters and transceivers are just used 108 108
to convert copper to fiber optic, fiber optic to copper, 109 109
but we can also use them for coaxial the fiber 110 110
or fiber to coaxial or any other layer one, 111 111
to layer one conversion you may need to do 112 112
within your networks. 113 113
These transceivers are simply a device 114 114
that send and receive data. 115 115
Transceivers are transmit receivers. 116 116
They can operate either bi-directional or full-duplex modes. 117 117
Now we haven't talked a lot about bi-directional versus 118 118
duplex communication yet. 119 119
So let's stop and cover that for a moment here. 120 120
If a communication is bi-directional, 121 121
that means it has to take turns when communicating. 122 122
So if you use a walkie-talkie as a kid in the old days, 123 123
you might be familiar with this concept. 124 124
You'd pick up the walkie-talkie and you'd press the button 125 125
and you'd say something. 126 126
Now, while you were talking, your buddy on the other side 127 127
had the other walkie-talkie, but they couldn't 128 128
key up and talk at the same time, 129 129
because it's using bi-directional communication. 130 130
One person talks, and the other person has to listen. 131 131
This way we take turns. 132 132
This is also known as half-duplex because only one side 133 133
of the connection can use all the bandwidth 134 134
at any given time. 135 135
So when your friend is talking, you have to listen. 136 136
If you're talking, your friend has to listen. 137 137
You both can't talk at the same time. 138 138
This is a half-duplex communication. 139 139
Now, the other way we can communicate is using something 140 140
called full-duplex. 141 141
Full-duplex mode allows both devices to communicate 142 142
at the same time and they have access to the bandwidth 143 143
and they share it. 144 144
This is like, if you were going to pick up the phone 145 145
and call me both you and I can talk simultaneously, 146 146
you can talk and I can listen, 147 147
or I can talk and you can listen. 148 148
This would happen just like half-duplex mode. 149 149
But if I said something you don't like, 150 150
you can actually shout over me because we have the ability 151 151
to talk at the same time. 152 152
This is why it's called full-duplex communication. 153 153
With the walkie-talkie, we couldn't do that 154 154
because we were using bi-directional, 155 155
half-duplex communication, 156 156
but with the full-duplex capability of a telephone, 157 157
we can both talk and listen at the same time. 158 158
Now with that said, 159 159
let's go back to our discussion of transceivers. 160 160
You actually find that in a lot of large networks, 161 161
you're going to end up using these transceivers 162 162
or transmit receivers a lot. 163 163
For example, we have a thing called the GBIC module, GBIC. 164 164
This is going to exist in our routers and our switches. 165 165
Now a GBIC is a standard hot-pluggable gigabit ethernet 166 166
transceiver that can take in copper or fiber 167 167
as its connector. 168 168
Now, in addition to GBIC, 169 169
we also have some newer variants of these. 170 170
For instance, we have an SFP 171 171
or a small form-factor pluggable. 172 172
An SFP is a smaller module than a GBIC, and it's basically 173 173
a compact and hot-pluggable optical module 174 174
that's used with fiber connections and it could be plugged 175 175
in or out of that switch or router 176 176
without turning off the device. 177 177
Now, an SFP is a transceiver and it supports up to 4.25 178 178
gigabytes per second of speed. 179 179
Sometimes you're going to hear an SFP called a mini GBIC 180 180
because it's about half the size of a standard GBIC module. 181 181
The next transceiver you might find is known as an SFP+ 182 182
or small form-factor pluggable plus module. 183 183
It's essentially a faster version of an SFP instead of 4.25 184 184
gigabytes per second, we're going to be able to support 185 185
10 gigabytes per second. 186 186
So it's about twice as fast as a regular SFP. 187 187
Now moving into faster and faster modules, 188 188
we have a QSFP or a Quad Small Form-factor Plugable. 189 189
Again, this is another type of optical module transceiver, 190 190
just like SFP, just like SFP+, and just like GBIC. 191 191
The big difference here 192 192
is that it's going faster and faster. 193 193
This time we can go about 40 gigabytes per second. 194 194
Then we have QSFP+, 195 195
this is a Quad Small Form-factor pluggable plus. 196 196
As you might've guessed, it is just like a QSFP, 197 197
but it's faster. 198 198
It's another optical module, just like QSFP, SFP+, 199 199
SFP and GBIC. 200 200
But it's going to operate at faster speeds. 201 201
This one can go up to 41.2 gigabytes per second. 202 202
Now there's also newer variants of QSFP like QSFP 28, 203 203
which operates up to 100 gigabytes per second. 204 204
And QSFP 56, which operates up to 200 gigabytes per second. 205 205
Now, at the end of the day, though, 206 206
these are all just different types of transceivers 207 207
converting the light that travels over a fiber optic cable 208 208
into an electrical one or zero that our copper network 209 209
switches and cables are going to be able to utilize. 210 210
All of these pluggable modules are installed directly 211 211
into a switch or router. 212 212
But sometimes you need to run a fiber optic cable 213 213
for a single workstation or a single server 214 214
because it's beyond the a 100 meter limit 215 215
of your traditional CAT 5, six or seven cables. 216 216
Now you can do that as well. 217 217
You simply need to use a media converter or transceiver 218 218
to convert the copper cable to fiber on one end, 219 219
then you run your fiber cable and on the other end, 220 220
you put another media converter to go from fiber 221 221
back to copper. 222 222
This essentially converts an electrical signal 223 223
to an optical signal, 224 224
that can be pushed over a long distance, 225 225
and then converting it back on the other side 226 226
into an electrical signal, 227 227
to push it back into a copper cable 228 228
where it can reach your network adapter 229 229
and go back into your computer. 230 230
So if you ever need to switch the physical format 231 231
of your networks to cross a greater distance, have no fear. 232 232
You can convert that CAT 7 cable into a fiber optic cable 233 233
simply by using a stand-alone media converter 234 234
or transceiver, send it over a couple of miles 235 235
across your campus or across your city. 236 236
And then reconvert it on the other side 237 237
with another media converter or transceiver.