WEBVTT 1 00:00:00.330 --> 00:00:02.010 The next type of cable we need to talk 2 00:00:02.010 --> 00:00:03.960 about is fiber optic cables. 3 00:00:03.960 --> 00:00:06.060 Now fiber optic cables are going to use light 4 00:00:06.060 --> 00:00:08.190 from an LED, a light emitting diode, 5 00:00:08.190 --> 00:00:10.500 or a laser to transmit information 6 00:00:10.500 --> 00:00:12.570 through a thin piece of glass fiber. 7 00:00:12.570 --> 00:00:14.220 Now fiber optic cables are great 8 00:00:14.220 --> 00:00:16.380 because they're immune to electromagnetic interference, 9 00:00:16.380 --> 00:00:18.900 or EMI, because there's no electricity involved 10 00:00:18.900 --> 00:00:21.780 in the data transmission as it's going down that cable. 11 00:00:21.780 --> 00:00:24.450 Also, because we're using light instead of electricity, 12 00:00:24.450 --> 00:00:26.850 our signal can go an extremely long distance 13 00:00:26.850 --> 00:00:29.370 without much attenuation or signal loss. 14 00:00:29.370 --> 00:00:31.650 Whereas our copper cables, specifically CAT3 15 00:00:31.650 --> 00:00:34.320 through CAT7 could only go about 100 meters. 16 00:00:34.320 --> 00:00:35.940 Fiber optic cables can go hundreds 17 00:00:35.940 --> 00:00:38.160 of meters or even hundreds of miles. 18 00:00:38.160 --> 00:00:40.860 After all, we have some really long fiber optic cables 19 00:00:40.860 --> 00:00:42.210 that are sitting on the ocean floor 20 00:00:42.210 --> 00:00:43.680 between the United States and Europe. 21 00:00:43.680 --> 00:00:46.860 And that is a huge distance all the way across the Atlantic. 22 00:00:46.860 --> 00:00:48.540 Now, this is one of the biggest benefits 23 00:00:48.540 --> 00:00:49.830 of fiber optic cables. 24 00:00:49.830 --> 00:00:53.250 It can cover an expansive range and longer distances. 25 00:00:53.250 --> 00:00:55.740 In addition to that, we can turn the light on and off 26 00:00:55.740 --> 00:00:58.530 very quickly adding to higher bandwidth applications 27 00:00:58.530 --> 00:00:59.940 by using fiber. 28 00:00:59.940 --> 00:01:02.250 If you remember from our copper media discussions, 29 00:01:02.250 --> 00:01:04.530 we were talking in terms of 10 megabits per second, 30 00:01:04.530 --> 00:01:07.350 100 megabits per second, one gigabit per second, 31 00:01:07.350 --> 00:01:09.750 10 gigabits per second, and things like that. 32 00:01:09.750 --> 00:01:11.970 But now that we've moved on to fiber, we can start talking 33 00:01:11.970 --> 00:01:14.340 about things in the terabits per second range. 34 00:01:14.340 --> 00:01:16.500 In fact, all the way back in 2012, 35 00:01:16.500 --> 00:01:19.140 the Japanese telecommunications company NTT 36 00:01:19.140 --> 00:01:22.380 was able to send data at one petabit per second. 37 00:01:22.380 --> 00:01:24.570 Now that is really, really fast. 38 00:01:24.570 --> 00:01:26.430 And so fiber is starting to be used 39 00:01:26.430 --> 00:01:28.530 in a lot of extremely fast networks. 40 00:01:28.530 --> 00:01:30.630 And it's usually not the fiber cable that becomes 41 00:01:30.630 --> 00:01:32.430 your limitation in the network anymore. 42 00:01:32.430 --> 00:01:34.710 Instead, it's your other networking equipment, 43 00:01:34.710 --> 00:01:36.270 things like your switches and your routers 44 00:01:36.270 --> 00:01:38.940 and your end user devices, they just can't keep up. 45 00:01:38.940 --> 00:01:41.850 And so for this reason, most business class networks 46 00:01:41.850 --> 00:01:44.940 are still going to use fiber around 10 gigabits per second 47 00:01:44.940 --> 00:01:46.770 because of those switches and routers. 48 00:01:46.770 --> 00:01:48.990 But this is more of a cost benefit decision 49 00:01:48.990 --> 00:01:52.260 than a technical limitation of the fiber cables themself. 50 00:01:52.260 --> 00:01:55.710 So, if fiber is so great with a huge expansive range 51 00:01:55.710 --> 00:01:57.180 and super high speeds, 52 00:01:57.180 --> 00:01:58.680 there's got to be some drawbacks, right? 53 00:01:58.680 --> 00:02:00.570 Why isn't everyone using fiber? 54 00:02:00.570 --> 00:02:03.720 Well, we really do have two main drawbacks of fiber. 55 00:02:03.720 --> 00:02:05.820 First, fiber is expensive. 56 00:02:05.820 --> 00:02:07.800 Now the price of fiber continues to drop 57 00:02:07.800 --> 00:02:09.180 and it has year over year, 58 00:02:09.180 --> 00:02:11.880 but it's still much more expensive than a copper network. 59 00:02:11.880 --> 00:02:14.520 For this reason, most businesses only use fiber 60 00:02:14.520 --> 00:02:16.170 to connect backbones of their networks 61 00:02:16.170 --> 00:02:18.900 to their red switches or they're going to use fiber 62 00:02:18.900 --> 00:02:20.280 if they need to cover a large distance 63 00:02:20.280 --> 00:02:22.020 that they can't cover with copper. 64 00:02:22.020 --> 00:02:25.020 Second, fiber is more difficult to work with than copper. 65 00:02:25.020 --> 00:02:26.970 In fact, when I teach in the classroom, 66 00:02:26.970 --> 00:02:28.200 I teach my students how to build 67 00:02:28.200 --> 00:02:29.910 their own Cat 5e cables. 68 00:02:29.910 --> 00:02:33.120 Now for less than $10, I can get each student a crimper, 69 00:02:33.120 --> 00:02:35.130 a set of connectors, and a cable tester 70 00:02:35.130 --> 00:02:37.020 and they can take it home with them and they can do it 71 00:02:37.020 --> 00:02:39.720 in about 10 minutes to learn how to build their own cables. 72 00:02:39.720 --> 00:02:41.040 It's really easy. 73 00:02:41.040 --> 00:02:43.260 Now, fiber on the other hand is much more difficult 74 00:02:43.260 --> 00:02:45.450 to work with and it requires special tools 75 00:02:45.450 --> 00:02:47.970 and training to learn how to make those fiber cables 76 00:02:47.970 --> 00:02:50.190 or to repair broken fiber cables. 77 00:02:50.190 --> 00:02:52.980 In my experience, it costs about five to 10 times more 78 00:02:52.980 --> 00:02:55.860 to run a fiber cable than it does to run a copper cable 79 00:02:55.860 --> 00:02:58.800 inside an office building or between office buildings. 80 00:02:58.800 --> 00:03:00.600 Now, even with the drawbacks and expense 81 00:03:00.600 --> 00:03:02.790 and difficulty of working with fiber optic cables, 82 00:03:02.790 --> 00:03:04.680 fiber optics definitely have a place 83 00:03:04.680 --> 00:03:06.300 in most enterprise networks. 84 00:03:06.300 --> 00:03:07.680 And so we need to spend some time going 85 00:03:07.680 --> 00:03:08.513 over the different types 86 00:03:08.513 --> 00:03:11.100 of fiber optic cables that you may come across. 87 00:03:11.100 --> 00:03:13.770 First, we need to categorize our fiber optic cables 88 00:03:13.770 --> 00:03:15.840 and we do this as either single mode fibers 89 00:03:15.840 --> 00:03:17.430 or multimode fibers. 90 00:03:17.430 --> 00:03:20.100 Now single mode fibers or SMF is a type 91 00:03:20.100 --> 00:03:22.230 of fiber optic cable that carries a single beam 92 00:03:22.230 --> 00:03:24.270 of light directly from one end of the cable 93 00:03:24.270 --> 00:03:25.830 to the other end of the cable. 94 00:03:25.830 --> 00:03:28.380 To achieve this, a single mode fiber has a smaller 95 00:03:28.380 --> 00:03:30.990 and thinner core than does a multi-mode fiber. 96 00:03:30.990 --> 00:03:32.430 Now single mode fiber is used 97 00:03:32.430 --> 00:03:33.900 for long distance communications 98 00:03:33.900 --> 00:03:35.220 due to its smaller core size 99 00:03:35.220 --> 00:03:37.920 of 8.3 to 10 microns in diameter. 100 00:03:37.920 --> 00:03:39.570 This smaller core size allows 101 00:03:39.570 --> 00:03:41.340 for a more precise signal transmission 102 00:03:41.340 --> 00:03:44.220 over a longer distance because it forces the light to travel 103 00:03:44.220 --> 00:03:46.080 along a single path down the center 104 00:03:46.080 --> 00:03:48.600 of that cable without being dispersed around. 105 00:03:48.600 --> 00:03:50.490 Now, if you see workers with a large roll 106 00:03:50.490 --> 00:03:52.320 of fiber optic cable in your neighborhood, 107 00:03:52.320 --> 00:03:54.750 this is usually going to be a single mode fiber 108 00:03:54.750 --> 00:03:56.790 and they're going to be able to cover a long distance 109 00:03:56.790 --> 00:03:59.010 from their internet service providers facility all the way 110 00:03:59.010 --> 00:03:59.970 into your neighborhood. 111 00:03:59.970 --> 00:04:01.440 And that's why they do it. 112 00:04:01.440 --> 00:04:03.180 The second type of fiber we have is known 113 00:04:03.180 --> 00:04:05.640 as multimode fiber or MMF. 114 00:04:05.640 --> 00:04:07.290 Now multimode fiber is a type 115 00:04:07.290 --> 00:04:09.510 of fiber optic cable that carries a beam of light 116 00:04:09.510 --> 00:04:11.100 as its data transmission media, 117 00:04:11.100 --> 00:04:12.780 just like a single mode fiber, 118 00:04:12.780 --> 00:04:15.210 but it uses a thicker core size. 119 00:04:15.210 --> 00:04:16.950 Now multimode fiber cores are 120 00:04:16.950 --> 00:04:19.500 between 50 to 100 microns in diameter. 121 00:04:19.500 --> 00:04:21.780 This makes them about six to 10 times larger 122 00:04:21.780 --> 00:04:23.820 than a single mode fiber's core. 123 00:04:23.820 --> 00:04:26.520 Now 50 to a 100 microns might sound pretty small 124 00:04:26.520 --> 00:04:29.070 and it is relatively, I mean an average human hair 125 00:04:29.070 --> 00:04:31.170 is only about 70 microns in diameter. 126 00:04:31.170 --> 00:04:33.150 This is still an increased core size 127 00:04:33.150 --> 00:04:35.040 over the size of a single mode fiber. 128 00:04:35.040 --> 00:04:37.740 And it allows light to start bouncing around and refracting 129 00:04:37.740 --> 00:04:39.450 as it's traveling down the cable. 130 00:04:39.450 --> 00:04:41.880 Due to this, multimode fiber is usually going to be used 131 00:04:41.880 --> 00:04:44.550 in shorter distances, up to around two kilometers 132 00:04:44.550 --> 00:04:45.810 or less in size. 133 00:04:45.810 --> 00:04:47.910 And that's about a mile in distance. 134 00:04:47.910 --> 00:04:50.760 Now multimode fibers are commonly used in the same place 135 00:04:50.760 --> 00:04:53.130 you're going to normally use a copper patch cable. 136 00:04:53.130 --> 00:04:55.530 For example, if you're going to be using a multimode fiber 137 00:04:55.530 --> 00:04:57.000 to connect a router to a switch 138 00:04:57.000 --> 00:04:59.700 or a switch to a switch or switches to servers, 139 00:04:59.700 --> 00:05:01.680 any place you'd normally use a patch cable 140 00:05:01.680 --> 00:05:03.480 or even a cable run between your patch cable 141 00:05:03.480 --> 00:05:05.430 and your wall jack, could be a place you use 142 00:05:05.430 --> 00:05:07.410 a multimode fiber instead. 143 00:05:07.410 --> 00:05:09.420 For the exam, you do not need to memorize 144 00:05:09.420 --> 00:05:10.980 the exact size of the cores 145 00:05:10.980 --> 00:05:12.930 for single mode or multimode fibers. 146 00:05:12.930 --> 00:05:14.460 They're not going to ask you that. 147 00:05:14.460 --> 00:05:17.130 Instead, you need to remember the multimode fibers 148 00:05:17.130 --> 00:05:18.900 are going to have a larger core size, 149 00:05:18.900 --> 00:05:21.300 therefore they cannot cover longer distances 150 00:05:21.300 --> 00:05:23.100 the way a single mode fiber can. 151 00:05:23.100 --> 00:05:25.770 If you need to pick out a cable to cover a longer distance, 152 00:05:25.770 --> 00:05:28.680 you want to make sure you're selecting a single mode fiber. 153 00:05:28.680 --> 00:05:31.680 Remember, single mode fibers have a much smaller core size 154 00:05:31.680 --> 00:05:33.840 and therefore, light can only travel in one direction 155 00:05:33.840 --> 00:05:34.673 down that cable. 156 00:05:34.673 --> 00:05:36.480 If you have a multimode fiber, 157 00:05:36.480 --> 00:05:37.680 the light can bounce around more 158 00:05:37.680 --> 00:05:39.270 because of the larger core size. 159 00:05:39.270 --> 00:05:41.160 And therefore you're going to have less distance 160 00:05:41.160 --> 00:05:43.830 with multimode fiber because you have more noise. 161 00:05:43.830 --> 00:05:45.630 This means multimode fibers tend to be less 162 00:05:45.630 --> 00:05:48.420 expensive to build and buy, and they're cheaper to install 163 00:05:48.420 --> 00:05:49.650 than a single mode fiber. 164 00:05:49.650 --> 00:05:51.450 So a lot of network designers will actually 165 00:05:51.450 --> 00:05:53.760 implement solutions that use multimode fibers 166 00:05:53.760 --> 00:05:56.070 over single mode fibers whenever possible. 167 00:05:56.070 --> 00:05:58.950 And to do that, they'll make sure they have lower distances. 168 00:05:58.950 --> 00:06:01.200 So maybe they'll go 500 meters between switches 169 00:06:01.200 --> 00:06:03.300 instead of two kilometers per switch. 170 00:06:03.300 --> 00:06:04.980 Now, if you happen to be working in the field 171 00:06:04.980 --> 00:06:06.360 and you're trying to identify a cable 172 00:06:06.360 --> 00:06:08.670 as either a single mode or multimode fiber, 173 00:06:08.670 --> 00:06:10.860 the easiest way to do this is by simply looking 174 00:06:10.860 --> 00:06:12.180 at the color of the cable. 175 00:06:12.180 --> 00:06:13.980 If the cable has a yellow sheath on it, 176 00:06:13.980 --> 00:06:16.560 it's a single mode fiber or SMF cable. 177 00:06:16.560 --> 00:06:19.110 If the cable has an Aqua blue or orange color sheath, 178 00:06:19.110 --> 00:06:22.200 it means it's a multimode fiber or MMF cable. 179 00:06:22.200 --> 00:06:25.230 Now, regardless of whether you use single mode or multimode, 180 00:06:25.230 --> 00:06:26.880 you still have to terminate these cables 181 00:06:26.880 --> 00:06:27.713 with some kind of a connector 182 00:06:27.713 --> 00:06:29.760 so you can plug 'em in your devices. 183 00:06:29.760 --> 00:06:31.590 Now there's going to be four different connector types 184 00:06:31.590 --> 00:06:32.970 that you're going to come across. 185 00:06:32.970 --> 00:06:36.597 SC, ST, LC and MTRJ. 186 00:06:36.597 --> 00:06:39.180 For the exam, you need to be able to visually identify 187 00:06:39.180 --> 00:06:40.470 each of these connectors. 188 00:06:40.470 --> 00:06:41.970 If I showed you a picture of one, 189 00:06:41.970 --> 00:06:43.380 you need to be able to describe it 190 00:06:43.380 --> 00:06:45.180 and pick it out on the exam. 191 00:06:45.180 --> 00:06:47.640 So how are you going to remember which one is which? 192 00:06:47.640 --> 00:06:48.750 Well, don't worry. 193 00:06:48.750 --> 00:06:50.640 I got some memory aids to help you with this 194 00:06:50.640 --> 00:06:52.590 and make sure you get it right on the exam. 195 00:06:52.590 --> 00:06:54.480 First let's look at SC, 196 00:06:54.480 --> 00:06:56.430 which stands for Subscriber Connector. 197 00:06:56.430 --> 00:06:59.130 Now SC is fairly popular because they're low cost, 198 00:06:59.130 --> 00:07:01.290 they're durable, and they're easy to install. 199 00:07:01.290 --> 00:07:03.300 Some people call these the square connector 200 00:07:03.300 --> 00:07:04.800 or the standard connector. 201 00:07:04.800 --> 00:07:06.810 But personally, I like to call it the stick 202 00:07:06.810 --> 00:07:08.220 and click connector, 'cause it helps 203 00:07:08.220 --> 00:07:10.470 remember what it looks like on exam day. 204 00:07:10.470 --> 00:07:13.380 Now, when you look at an SC or a stick and click connector, 205 00:07:13.380 --> 00:07:14.460 you're going to see a little ridge 206 00:07:14.460 --> 00:07:17.550 on the top of it, a lot like an RJ45 connector. 207 00:07:17.550 --> 00:07:20.550 And when you push the SC into a network jack or wall jack, 208 00:07:20.550 --> 00:07:22.440 you're going to hear a little click that tells you 209 00:07:22.440 --> 00:07:23.970 it's inserted properly. 210 00:07:23.970 --> 00:07:26.160 Now this is why I call it the stick and click, 211 00:07:26.160 --> 00:07:27.660 because you stick it into the jack 212 00:07:27.660 --> 00:07:29.010 and you hear the click. 213 00:07:29.010 --> 00:07:31.200 With SC, you're usually going to see two cables 214 00:07:31.200 --> 00:07:34.530 bundled together, each one with its own SC connector on it 215 00:07:34.530 --> 00:07:36.870 and that way you can plug them into the jack. 216 00:07:36.870 --> 00:07:38.250 Each of these cables is going to be used 217 00:07:38.250 --> 00:07:40.260 for transmitting or receiving the data. 218 00:07:40.260 --> 00:07:43.800 So to transmit and receive, you need two cables. 219 00:07:43.800 --> 00:07:47.010 Next, we have an ST or Straight Tip Connector. 220 00:07:47.010 --> 00:07:49.680 Now the ST connector is also relatively low cost 221 00:07:49.680 --> 00:07:50.850 and easy to use. 222 00:07:50.850 --> 00:07:52.440 The ST is one of the older types 223 00:07:52.440 --> 00:07:54.840 of fiber connectors we have and just like SC, 224 00:07:54.840 --> 00:07:56.940 it has a transmit and receive cable 225 00:07:56.940 --> 00:07:59.280 each with its own ST connector on it. 226 00:07:59.280 --> 00:08:01.050 I like to call the ST connectors 227 00:08:01.050 --> 00:08:02.640 the stick and twist connector, 228 00:08:02.640 --> 00:08:04.350 because you're going to insert it into the jack 229 00:08:04.350 --> 00:08:05.850 and then turn it about half a turn 230 00:08:05.850 --> 00:08:07.800 to the right until it locks in place. 231 00:08:07.800 --> 00:08:10.320 Now you're not going to hear it click like an SC connector, 232 00:08:10.320 --> 00:08:12.660 but you are going to stick it in place and twist it 233 00:08:12.660 --> 00:08:15.000 until it locks and stops turning. 234 00:08:15.000 --> 00:08:17.820 Third, we have an LC or Lucent Connector. 235 00:08:17.820 --> 00:08:20.820 This is a newer and smaller version of an SC connector. 236 00:08:20.820 --> 00:08:22.830 Like the SC connector, it does use 237 00:08:22.830 --> 00:08:24.930 a stick and click connection to the jack. 238 00:08:24.930 --> 00:08:26.580 Now to remember the LC connector, 239 00:08:26.580 --> 00:08:28.230 instead of the SC connector, 240 00:08:28.230 --> 00:08:30.480 I like to call this the love connector. 241 00:08:30.480 --> 00:08:32.190 This is because you're almost always going to find 242 00:08:32.190 --> 00:08:34.650 the LC connector with its transmit and receive 243 00:08:34.650 --> 00:08:37.290 sides attached side by side, like lovers. 244 00:08:37.290 --> 00:08:40.170 You can actually place them together and they lock together. 245 00:08:40.170 --> 00:08:42.960 Whereas the SC is often found as two individual cables, 246 00:08:42.960 --> 00:08:46.320 the LC or love connector is almost always married together 247 00:08:46.320 --> 00:08:48.810 and they're coupled up right next to each other. 248 00:08:48.810 --> 00:08:51.750 Fourth, we have the MTRJ for Mechanical Transfer 249 00:08:51.750 --> 00:08:53.040 Registered Jack. 250 00:08:53.040 --> 00:08:55.320 MTRJ is a fiber optic cable connector 251 00:08:55.320 --> 00:08:57.000 that's very popular and widely used 252 00:08:57.000 --> 00:09:00.120 with networking devices because it is a smaller form factor. 253 00:09:00.120 --> 00:09:02.490 It's much smaller than the other three we talked about. 254 00:09:02.490 --> 00:09:05.070 Each MTRJ connector is going to have both the transmit 255 00:09:05.070 --> 00:09:06.630 and receive pins terminated 256 00:09:06.630 --> 00:09:08.940 inside a single plastic connector. 257 00:09:08.940 --> 00:09:11.760 And this is about half the size of an SC, ST, 258 00:09:11.760 --> 00:09:13.170 or LC connector. 259 00:09:13.170 --> 00:09:16.170 This means that by using an MTRJ, you can have a switch 260 00:09:16.170 --> 00:09:19.140 that fits 24 fiber reports in the same chassis size 261 00:09:19.140 --> 00:09:22.770 as a regular RJ45 24 port copper switch. 262 00:09:22.770 --> 00:09:25.650 Whereas with ST, SC, or LC, you'd only be able to get 263 00:09:25.650 --> 00:09:27.570 about 12 switch ports in there. 264 00:09:27.570 --> 00:09:30.507 Now, often you're going to see MTRJ used on fiber switches 265 00:09:30.507 --> 00:09:33.030 and they're going to connect to fiber patch distribution panels 266 00:09:33.030 --> 00:09:36.570 on one side, and the other side will convert it to SC, ST, 267 00:09:36.570 --> 00:09:39.903 or LC for distribution out to a wall jack into an office.