1 00:00:00,000 --> 00:00:00,960 [Instructor] In this lesson, 2 00:00:00,960 --> 00:00:03,060 we're going to discuss fiber media. 3 00:00:03,060 --> 00:00:04,350 Now, fiber media is used 4 00:00:04,350 --> 00:00:07,560 to transmit data using light instead of electrical impulses. 5 00:00:07,560 --> 00:00:09,810 And this type of fiber optic technology represents 6 00:00:09,810 --> 00:00:12,690 a significant leap in data transmission capabilities 7 00:00:12,690 --> 00:00:14,010 compared to our more traditional, 8 00:00:14,010 --> 00:00:15,960 copper media based networks. 9 00:00:15,960 --> 00:00:19,020 Fiber optic cables use light typically from LEDs 10 00:00:19,020 --> 00:00:23,040 or lasers to transmit data over glass or plastic cables. 11 00:00:23,040 --> 00:00:26,310 Fiber media has several key advantages over copper media, 12 00:00:26,310 --> 00:00:28,800 including an immunity to electromagnetic interference 13 00:00:28,800 --> 00:00:30,450 or EMI, the capability 14 00:00:30,450 --> 00:00:32,520 to transmit data over much longer distances 15 00:00:32,520 --> 00:00:34,410 without significant signal loss 16 00:00:34,410 --> 00:00:38,010 and the ability to reach much higher data transfer speeds. 17 00:00:38,010 --> 00:00:39,210 Fiber media is great 18 00:00:39,210 --> 00:00:41,850 because it is fully immune to the effects of EMI, 19 00:00:41,850 --> 00:00:44,700 because EMI can only be generated by electrical signals 20 00:00:44,700 --> 00:00:47,340 and it can only affect other electrical signals. 21 00:00:47,340 --> 00:00:50,100 Since fiber media relies on light to send its data, 22 00:00:50,100 --> 00:00:51,780 that light is not going to be affected 23 00:00:51,780 --> 00:00:54,240 by any outside electromagnetic interference, 24 00:00:54,240 --> 00:00:56,220 and it doesn't require a shielded cable 25 00:00:56,220 --> 00:00:57,930 to overcome the effects of EMI 26 00:00:57,930 --> 00:01:00,060 like a twisted pair cable might. 27 00:01:00,060 --> 00:01:02,940 When it comes to data transmission over longer distances, 28 00:01:02,940 --> 00:01:06,180 fiber optic cables are also superior to copper media. 29 00:01:06,180 --> 00:01:08,040 With twisted pair of copper cables, 30 00:01:08,040 --> 00:01:09,741 you're limited to about a hundred meters 31 00:01:09,741 --> 00:01:12,480 due to the signal degradating over time 32 00:01:12,480 --> 00:01:14,400 based on the resistance of the cable. 33 00:01:14,400 --> 00:01:16,410 If you're using coaxial copper cables, 34 00:01:16,410 --> 00:01:19,020 you can extend that to about 300 meters in length, 35 00:01:19,020 --> 00:01:21,030 but it will still degradate over time 36 00:01:21,030 --> 00:01:22,170 and the signal be reduced 37 00:01:22,170 --> 00:01:24,960 and no longer function after 300 meters. 38 00:01:24,960 --> 00:01:26,520 Now, when you're using fiber optic cables, 39 00:01:26,520 --> 00:01:28,830 on the other hand though, you can span not just hundreds 40 00:01:28,830 --> 00:01:31,560 of meters, but you can also span hundreds of miles 41 00:01:31,560 --> 00:01:33,630 with a single fiber optic cable. 42 00:01:33,630 --> 00:01:36,120 This makes fiber optic cables ideal for a wide range 43 00:01:36,120 --> 00:01:38,880 of applications from your local area network connections 44 00:01:38,880 --> 00:01:40,800 to transcontinental data transmission 45 00:01:40,800 --> 00:01:43,350 using underwater fiber optic cables. 46 00:01:43,350 --> 00:01:44,640 Now in terms of speed, 47 00:01:44,640 --> 00:01:47,460 fiber optic cables can reach blazingly fast speeds 48 00:01:47,460 --> 00:01:49,590 as compared to our copper cables. 49 00:01:49,590 --> 00:01:52,230 Most copper media is going to reach a maximum speed 50 00:01:52,230 --> 00:01:54,210 of around 10 gigabits per second 51 00:01:54,210 --> 00:01:56,790 and covering up to about a hundred meters in distance, 52 00:01:56,790 --> 00:01:58,830 but a fiber optic cable can reach 53 00:01:58,830 --> 00:02:00,270 much higher data transfer speeds 54 00:02:00,270 --> 00:02:03,330 even when crossing tens or hundreds of miles. 55 00:02:03,330 --> 00:02:05,700 In fact, all the way back in 2012, 56 00:02:05,700 --> 00:02:08,940 the Japanese telecommunications company NTT was able 57 00:02:08,940 --> 00:02:11,760 to send data at one petabit per second. 58 00:02:11,760 --> 00:02:14,460 Fiber is used in extremely fast networks, 59 00:02:14,460 --> 00:02:16,050 and it's usually not the fiber cable 60 00:02:16,050 --> 00:02:17,100 that becomes the bottleneck 61 00:02:17,100 --> 00:02:19,260 or limitation in our networks anymore. 62 00:02:19,260 --> 00:02:21,930 But instead, it's going to be our networking equipment 63 00:02:21,930 --> 00:02:25,440 such as our routers, our switches, and our end user devices. 64 00:02:25,440 --> 00:02:26,520 For this reason, 65 00:02:26,520 --> 00:02:29,040 most business class networks are going to use fiber 66 00:02:29,040 --> 00:02:31,440 that are operating at around 10 gigabits per second, 67 00:02:31,440 --> 00:02:33,660 but that is more of a cost benefit decision 68 00:02:33,660 --> 00:02:35,370 than an actual technical limitation 69 00:02:35,370 --> 00:02:37,590 of the fiber cables themself. 70 00:02:37,590 --> 00:02:39,660 You're going to find that most fiber optic networks 71 00:02:39,660 --> 00:02:42,480 are operating in this range of 10 gigabits per second, 72 00:02:42,480 --> 00:02:43,440 or maybe these days, 73 00:02:43,440 --> 00:02:45,630 up to about a hundred gigabits per second 74 00:02:45,630 --> 00:02:47,790 due to those networking hardware limitations 75 00:02:47,790 --> 00:02:50,160 and trying to manage the business' overall cost 76 00:02:50,160 --> 00:02:51,840 to deploy their networks. 77 00:02:51,840 --> 00:02:53,760 So if fiber is so great, 78 00:02:53,760 --> 00:02:56,580 why aren't we all using it in every single network? 79 00:02:56,580 --> 00:02:59,160 Well, there's really two main drawbacks when it comes 80 00:02:59,160 --> 00:03:02,310 to fiber, and these are cost and complexity. 81 00:03:02,310 --> 00:03:05,070 Now, fiber optic media is actually pretty expensive, 82 00:03:05,070 --> 00:03:07,260 especially when compared to copper media. 83 00:03:07,260 --> 00:03:10,800 For example, a 25 foot fiber optic cable costs around 15 84 00:03:10,800 --> 00:03:13,170 to $20, where an equivalent 25 foot, 85 00:03:13,170 --> 00:03:16,980 copper twisted pair cable would cost us only around $5. 86 00:03:16,980 --> 00:03:19,590 But the network equipment to support the fiber instead 87 00:03:19,590 --> 00:03:23,190 of using copper is also going to be much more expensive too. 88 00:03:23,190 --> 00:03:25,380 The other consideration is that the complexity involved 89 00:03:25,380 --> 00:03:27,510 in using fiber optic cables is much higher. 90 00:03:27,510 --> 00:03:29,580 Fiber optic cables are actually much more difficult 91 00:03:29,580 --> 00:03:31,530 to work with than using a twisted pair 92 00:03:31,530 --> 00:03:33,570 or coaxial copper cable. 93 00:03:33,570 --> 00:03:34,530 In fact, when I used 94 00:03:34,530 --> 00:03:36,630 to teach this course in a classroom environment, 95 00:03:36,630 --> 00:03:38,400 I would actually give my students their own kit 96 00:03:38,400 --> 00:03:41,880 to create a CAT5e or CAT6a twisted pair of cable. 97 00:03:41,880 --> 00:03:45,150 These kits included a crimper, connectors, a cable tester, 98 00:03:45,150 --> 00:03:47,370 and about a hundred feet of cable for them to use, 99 00:03:47,370 --> 00:03:51,120 and the entire kit cost me around 10 to $15 per student. 100 00:03:51,120 --> 00:03:53,310 Then within about 10 minutes of me teaching my students 101 00:03:53,310 --> 00:03:55,650 how to create their own cables, they could effectively build 102 00:03:55,650 --> 00:03:57,450 their own copper patch cables themself 103 00:03:57,450 --> 00:03:59,610 and take it home with them after class. 104 00:03:59,610 --> 00:04:02,430 Now, fiber though is much more difficult to work with. 105 00:04:02,430 --> 00:04:03,960 It's going to require special tools 106 00:04:03,960 --> 00:04:06,210 and training to learn how to make fiber cables 107 00:04:06,210 --> 00:04:08,550 or to repair broken fiber cables. 108 00:04:08,550 --> 00:04:10,920 In my experience, it actually costs between five 109 00:04:10,920 --> 00:04:12,990 and 10 times more to run a fiber cable 110 00:04:12,990 --> 00:04:15,720 within an office building as it does to run a copper cable 111 00:04:15,720 --> 00:04:17,430 across a similar distance. 112 00:04:17,430 --> 00:04:19,620 In fact, even the tools are more expensive. 113 00:04:19,620 --> 00:04:22,260 As I said, I can buy an entire copper cable kit 114 00:04:22,260 --> 00:04:24,090 for about 10 to $15, 115 00:04:24,090 --> 00:04:28,020 but a fiber kit will cost me about 150 to $250. 116 00:04:28,020 --> 00:04:30,300 So it is much, much more expensive. 117 00:04:30,300 --> 00:04:32,550 Now, even with these drawbacks of the higher costs 118 00:04:32,550 --> 00:04:34,710 and fiber being more difficult to work with, though, 119 00:04:34,710 --> 00:04:37,380 fiber optic cables definitely have a place in most 120 00:04:37,380 --> 00:04:38,760 of our enterprise networks. 121 00:04:38,760 --> 00:04:39,930 So we're going to have to spend a little bit 122 00:04:39,930 --> 00:04:41,700 of time going over the two main types 123 00:04:41,700 --> 00:04:44,400 of fiber optic cables that you need to be aware of. 124 00:04:44,400 --> 00:04:47,400 These are single-mode fiber and multi-mode fiber. 125 00:04:47,400 --> 00:04:49,740 Now, first we have single-mode fiber, 126 00:04:49,740 --> 00:04:52,860 single-mode fiber, also known as SMF, is designed 127 00:04:52,860 --> 00:04:54,750 for long distance communication. 128 00:04:54,750 --> 00:04:56,520 It features a small glass core 129 00:04:56,520 --> 00:05:00,210 and is typically around 8.3 to 10 microns in diameter. 130 00:05:00,210 --> 00:05:02,070 Now, to put that in perspective for you, 131 00:05:02,070 --> 00:05:04,980 the diameter of a human hair is only 17 132 00:05:04,980 --> 00:05:08,490 to 180 microns in diameter depending on the person. 133 00:05:08,490 --> 00:05:10,500 So even at its smallest and thinnest, 134 00:05:10,500 --> 00:05:13,230 a human hair is still about two times larger 135 00:05:13,230 --> 00:05:15,540 than the fiber core of a single-mode fiber. 136 00:05:15,540 --> 00:05:17,160 And at its thickest type of hair, 137 00:05:17,160 --> 00:05:19,650 we're actually talking about 18 to 20 times as large 138 00:05:19,650 --> 00:05:22,830 as a single fiber inside of our fiber optic cables. 139 00:05:22,830 --> 00:05:25,320 Now, due to this very tiny fiber core, 140 00:05:25,320 --> 00:05:27,900 the light can only travel down a single path 141 00:05:27,900 --> 00:05:30,270 without causing much dispersion of that light, 142 00:05:30,270 --> 00:05:33,510 which is why we call this type of fiber a single-mode fiber. 143 00:05:33,510 --> 00:05:36,570 Because the light travel down a single path. 144 00:05:36,570 --> 00:05:38,850 This type pathway for the light beam enables 145 00:05:38,850 --> 00:05:41,400 the single-mode fiber to carry signals over longer distance 146 00:05:41,400 --> 00:05:43,890 of up to tens or even hundreds of miles. 147 00:05:43,890 --> 00:05:45,780 This makes single-mode fiber the preferred way 148 00:05:45,780 --> 00:05:47,970 for backbone installations in large networks, 149 00:05:47,970 --> 00:05:48,900 as well as for connections 150 00:05:48,900 --> 00:05:50,310 between different network segments 151 00:05:50,310 --> 00:05:52,500 that are spread over vast areas of land. 152 00:05:52,500 --> 00:05:55,530 If you need support for high bandwidth over long distances, 153 00:05:55,530 --> 00:05:57,240 you really should be considering the use 154 00:05:57,240 --> 00:06:00,600 of a single-mode fiber for your network's application. 155 00:06:00,600 --> 00:06:02,880 Second, we have multi-mode fiber. 156 00:06:02,880 --> 00:06:03,990 Now, multi-mode fiber 157 00:06:03,990 --> 00:06:06,750 or MMF is tailored for shorter distances 158 00:06:06,750 --> 00:06:08,880 because there's a larger fiber core size 159 00:06:08,880 --> 00:06:11,610 that ranges from 50 to a hundred microns. 160 00:06:11,610 --> 00:06:13,860 So again, this is a very small core, 161 00:06:13,860 --> 00:06:15,510 but it is still five times larger 162 00:06:15,510 --> 00:06:17,850 than a single-mode fiber core was. 163 00:06:17,850 --> 00:06:19,950 Now, because of this larger fiber core, 164 00:06:19,950 --> 00:06:22,170 it's going to allow light to travel in multiple paths 165 00:06:22,170 --> 00:06:24,030 or modes, which can be beneficial 166 00:06:24,030 --> 00:06:26,700 for transmitting data over shorter distances. 167 00:06:26,700 --> 00:06:29,730 But this larger core size does mean that there is more room 168 00:06:29,730 --> 00:06:31,830 for dispersion of the light signal to occur, 169 00:06:31,830 --> 00:06:33,090 and this will then effectively limit 170 00:06:33,090 --> 00:06:34,830 the transmission distance that you're going to be able 171 00:06:34,830 --> 00:06:37,410 to achieve over a multi-mode fiber cable. 172 00:06:37,410 --> 00:06:40,290 Now, the reason people use multi-mode over a single-mode is 173 00:06:40,290 --> 00:06:43,380 really cost because they have a larger core, they're cheaper 174 00:06:43,380 --> 00:06:45,750 to manufacture than those with a smaller core 175 00:06:45,750 --> 00:06:48,120 because it uses less precise equipment. 176 00:06:48,120 --> 00:06:50,700 Now, multi-mode fiber cables are commonly going to be used 177 00:06:50,700 --> 00:06:52,890 within buildings or across smaller campuses 178 00:06:52,890 --> 00:06:54,600 or business parks because they're suitable 179 00:06:54,600 --> 00:06:56,220 for connecting servers and switches 180 00:06:56,220 --> 00:06:57,750 or interconnecting network equipment 181 00:06:57,750 --> 00:06:59,580 within a single data center. 182 00:06:59,580 --> 00:07:02,190 If you need higher data rates over shorter distances, 183 00:07:02,190 --> 00:07:04,050 then a multi-mode fiber is a good choice 184 00:07:04,050 --> 00:07:06,960 to consider over using a copper media cable. 185 00:07:06,960 --> 00:07:09,090 Now, when I refer to a shorter distance in terms 186 00:07:09,090 --> 00:07:10,470 of fiber optic cables, 187 00:07:10,470 --> 00:07:12,480 what I'm really talking about is anything under 188 00:07:12,480 --> 00:07:15,750 about 2000 meters in length, which is about two kilometers 189 00:07:15,750 --> 00:07:17,400 or about one mile. 190 00:07:17,400 --> 00:07:18,690 So this is still much longer 191 00:07:18,690 --> 00:07:20,310 than our traditional copper cables, 192 00:07:20,310 --> 00:07:22,530 but not up to the several hundred miles 193 00:07:22,530 --> 00:07:25,440 that could be covered by a single-mode fiber cable. 194 00:07:25,440 --> 00:07:27,870 So I usually consider multi-mode fibers for use 195 00:07:27,870 --> 00:07:29,280 in the same places where you would 196 00:07:29,280 --> 00:07:31,530 normally use a copper patch cable. 197 00:07:31,530 --> 00:07:34,680 For example, you may use multi-mode fiber to connect routers 198 00:07:34,680 --> 00:07:38,190 and switches, switches to switches, or switches to servers. 199 00:07:38,190 --> 00:07:40,080 Any place you'd normally use a patch cable 200 00:07:40,080 --> 00:07:42,030 or even a cable run between your patch panel 201 00:07:42,030 --> 00:07:44,100 and your wall jack could be a good place 202 00:07:44,100 --> 00:07:46,020 to use a multi-mode fiber instead. 203 00:07:46,020 --> 00:07:47,850 That way, you can get higher speed 204 00:07:47,850 --> 00:07:48,750 and you won't be subject 205 00:07:48,750 --> 00:07:50,940 to any electromagnetic interference. 206 00:07:50,940 --> 00:07:52,620 So you may be wondering, 207 00:07:52,620 --> 00:07:54,450 how can I tell a multi-mode fiber 208 00:07:54,450 --> 00:07:56,040 from a single-mode fiber apart 209 00:07:56,040 --> 00:07:58,140 when I'm working as a network technician? 210 00:07:58,140 --> 00:08:00,720 Well, the easiest way for you to identify each of them is 211 00:08:00,720 --> 00:08:03,000 by the color of the cable itself. 212 00:08:03,000 --> 00:08:05,730 Now, if you see a cable that has a yellow plastic wrap 213 00:08:05,730 --> 00:08:08,040 or sheath around it, this is going to be considered 214 00:08:08,040 --> 00:08:11,160 a single-mode fiber or an SMF cable. 215 00:08:11,160 --> 00:08:12,660 If the cable has an aqua blue 216 00:08:12,660 --> 00:08:14,520 or orange color sheath around it, 217 00:08:14,520 --> 00:08:18,090 then it's going to be a multi-mode fiber or MMF cable. 218 00:08:18,090 --> 00:08:19,230 Now, this is a standard 219 00:08:19,230 --> 00:08:22,080 that almost every cable manufacturer is going to follow, 220 00:08:22,080 --> 00:08:24,450 because otherwise it becomes pretty impossible 221 00:08:24,450 --> 00:08:27,240 to tell the difference with your own eyes because the size 222 00:08:27,240 --> 00:08:30,300 and the diameter is still so much smaller than a human hair, 223 00:08:30,300 --> 00:08:31,800 and so we can't really see that difference 224 00:08:31,800 --> 00:08:33,030 between those two cables 225 00:08:33,030 --> 00:08:36,299 by just looking at them if we don't have that color scheme. 226 00:08:36,299 --> 00:08:38,159 So remember, there are two main types 227 00:08:38,159 --> 00:08:40,860 of fiber optic cables out there, single-mode fiber, 228 00:08:40,860 --> 00:08:42,390 and multi-mode fiber. 229 00:08:42,390 --> 00:08:44,730 single-mode fiber, also known as SMF, 230 00:08:44,730 --> 00:08:47,460 has a smaller fiber core, which makes it highly efficient 231 00:08:47,460 --> 00:08:48,930 for long range transmissions 232 00:08:48,930 --> 00:08:51,930 by offering higher bandwidth over those longer distances, 233 00:08:51,930 --> 00:08:54,120 the smaller fiber core does force the light 234 00:08:54,120 --> 00:08:56,640 to travel down a single-mode fiber's core using 235 00:08:56,640 --> 00:08:58,650 a singular path that prevents diffusion 236 00:08:58,650 --> 00:09:01,230 of the light being transmitted down that cable. 237 00:09:01,230 --> 00:09:04,560 Multi-mode fiber on the other hand, which we also call MMF, 238 00:09:04,560 --> 00:09:06,870 has a larger fiber core that will limit the distance 239 00:09:06,870 --> 00:09:08,310 that your data can be transmitted 240 00:09:08,310 --> 00:09:09,870 since that light signal can bounce 241 00:09:09,870 --> 00:09:11,610 around the inner fiber core more 242 00:09:11,610 --> 00:09:14,040 and becomes subject to that light diffusion. 243 00:09:14,040 --> 00:09:16,320 Because of this, multi-mode fiber does tend 244 00:09:16,320 --> 00:09:17,580 to be less expensive to buy 245 00:09:17,580 --> 00:09:19,830 and install than a single-mode fiber would. 246 00:09:19,830 --> 00:09:22,860 So a lot of network designers try to implement solutions 247 00:09:22,860 --> 00:09:25,260 that allow them to use multi-mode over single-mode 248 00:09:25,260 --> 00:09:27,660 whenever it's possible because it's easier to work with 249 00:09:27,660 --> 00:09:28,860 than a single-mode fiber 250 00:09:28,860 --> 00:09:31,080 and a lot cheaper to install. 251 00:09:31,080 --> 00:09:33,060 Multi-mode fiber is considered ideal 252 00:09:33,060 --> 00:09:34,800 for internal network infrastructures 253 00:09:34,800 --> 00:09:37,020 such as within an office building or data center, 254 00:09:37,020 --> 00:09:39,180 or as a replacement for copper patch cables 255 00:09:39,180 --> 00:09:41,790 in a high security environment or any environment 256 00:09:41,790 --> 00:09:43,320 that may be subject to higher levels 257 00:09:43,320 --> 00:09:45,003 of electromagnetic interference.