1 00:00:00,000 --> 00:00:00,900 In this lesson, 2 00:00:00,900 --> 00:00:03,210 we're going to explore wireless frequencies. 3 00:00:03,210 --> 00:00:05,340 Now, when I refer to wireless frequencies, 4 00:00:05,340 --> 00:00:06,911 I'm referring to the different frequency bands 5 00:00:06,911 --> 00:00:09,403 that we use to transmit and receive the radio waves 6 00:00:09,403 --> 00:00:12,840 that are being used by our wireless networks to send data. 7 00:00:12,840 --> 00:00:14,640 Each radio signal that's going to be transmitted 8 00:00:14,640 --> 00:00:16,560 or received must be sent or received 9 00:00:16,560 --> 00:00:18,330 at a specific frequency. 10 00:00:18,330 --> 00:00:20,580 Each frequency band has different characteristics 11 00:00:20,580 --> 00:00:22,680 that offer either more speed, more coverage, 12 00:00:22,680 --> 00:00:25,290 or more of both, depending on your needs. 13 00:00:25,290 --> 00:00:27,390 Each different frequency band is also regulated 14 00:00:27,390 --> 00:00:29,640 by governmental agencies to prevent interference 15 00:00:29,640 --> 00:00:31,620 between various communication services. 16 00:00:31,620 --> 00:00:34,110 So it's an important concept for you to understand. 17 00:00:34,110 --> 00:00:37,294 So in this lesson, let's take a look at the 2.4-gigahertz, 18 00:00:37,294 --> 00:00:39,907 5-gigahertz and 6-gigahertz frequency bands 19 00:00:39,907 --> 00:00:43,110 that are used with Wi-Fi networks, including a discussion 20 00:00:43,110 --> 00:00:44,970 about relevant government regulations, 21 00:00:44,970 --> 00:00:48,180 channel sizes, channel widths, and channel overlaps. 22 00:00:48,180 --> 00:00:49,740 Now, the first frequency band that we need 23 00:00:49,740 --> 00:00:52,860 to talk about is the 2.4-gigahertz frequency band. 24 00:00:52,860 --> 00:00:54,810 The 2.4-gigahertz band is one 25 00:00:54,810 --> 00:00:57,360 of the most widely used frequencies for wireless networking 26 00:00:57,360 --> 00:01:00,810 and has been in use since around 1997. 27 00:01:00,810 --> 00:01:03,403 The 2.4-gigahertz band is also known for its long range 28 00:01:03,403 --> 00:01:06,900 and better penetration through solid objects like drywall, 29 00:01:06,900 --> 00:01:09,390 studs, and other types of obstructions. 30 00:01:09,390 --> 00:01:11,370 Now, the 2.4-gigahertz frequency band 31 00:01:11,370 --> 00:01:12,870 actually contains frequencies 32 00:01:12,870 --> 00:01:15,660 from around 2.400 gigahertz, 33 00:01:15,660 --> 00:01:18,480 all the way up to 2.495 gigahertz. 34 00:01:18,480 --> 00:01:20,520 But most people will simply refer to this range 35 00:01:20,520 --> 00:01:23,370 as the 2.4-gigahertz frequency band. 36 00:01:23,370 --> 00:01:25,410 This frequency band is then divided up 37 00:01:25,410 --> 00:01:27,630 into channels using a given channel width, 38 00:01:27,630 --> 00:01:29,340 and these channels will also overlap 39 00:01:29,340 --> 00:01:31,680 with each other, which does cause some interference, 40 00:01:31,680 --> 00:01:33,390 so you need to be aware of that. 41 00:01:33,390 --> 00:01:35,040 Now, when I use the term channel, 42 00:01:35,040 --> 00:01:37,260 what I'm really talking about is a physical medium 43 00:01:37,260 --> 00:01:38,670 through which our wireless networks can 44 00:01:38,670 --> 00:01:40,320 send or receive data. 45 00:01:40,320 --> 00:01:42,030 Now this works much like a physical cable 46 00:01:42,030 --> 00:01:43,500 that we use in our wired networks, 47 00:01:43,500 --> 00:01:44,760 but instead of a physical copper 48 00:01:44,760 --> 00:01:47,252 or fiber cable, we're actually using a virtual cable 49 00:01:47,252 --> 00:01:50,130 that's just using a portion of the wireless frequencies 50 00:01:50,130 --> 00:01:52,230 that exists to create these virtual channels 51 00:01:52,230 --> 00:01:54,210 and send our data through the airwaves using a 52 00:01:54,210 --> 00:01:55,860 specific frequency. 53 00:01:55,860 --> 00:01:58,380 For example, channel one is going to be centered at 54 00:01:58,380 --> 00:02:00,450 2.412 gigahertz. 55 00:02:00,450 --> 00:02:02,700 But since the 2.4-gigahertz band 56 00:02:02,700 --> 00:02:04,860 uses a 22 megahertz channel width, 57 00:02:04,860 --> 00:02:08,699 channel one actually begins around 2.401 gigahertz 58 00:02:08,699 --> 00:02:11,700 and ends around 2.423 gigahertz. 59 00:02:11,700 --> 00:02:15,300 Channel two is centered on 2.417 gigahertz 60 00:02:15,300 --> 00:02:20,300 and begins at 2.406 gigahertz and ends at 2.428 gigahertz. 61 00:02:20,790 --> 00:02:22,110 This continues all the way through 62 00:02:22,110 --> 00:02:24,960 all the channels in the 2.4-gigahertz band. 63 00:02:24,960 --> 00:02:26,790 Now for the exam, you do not need 64 00:02:26,790 --> 00:02:28,950 to memorize the different frequencies associated 65 00:02:28,950 --> 00:02:30,390 with the different channels. 66 00:02:30,390 --> 00:02:33,475 Just be aware that the 2.4-gigahertz band does have a 67 00:02:33,475 --> 00:02:36,300 certain number of channels that you can use, 68 00:02:36,300 --> 00:02:38,880 and in our case, that's either going to be 11, 13 69 00:02:38,880 --> 00:02:42,000 or 14 depending on where you live in the world. 70 00:02:42,000 --> 00:02:43,320 Now, another thing you're going to have to notice 71 00:02:43,320 --> 00:02:44,400 when you look at these channels, 72 00:02:44,400 --> 00:02:47,520 is they actually overlap each other pretty significantly. 73 00:02:47,520 --> 00:02:48,930 Now, within each frequency band, 74 00:02:48,930 --> 00:02:50,790 there are specific frequencies and channels 75 00:02:50,790 --> 00:02:52,470 that we're going to use to avoid overlapping 76 00:02:52,470 --> 00:02:55,140 with other wireless signals in the same area. 77 00:02:55,140 --> 00:02:56,404 Now, the reason for this overlap is 78 00:02:56,404 --> 00:02:59,790 that the government only gave us 72 megahertz worth 79 00:02:59,790 --> 00:03:01,423 of bandwidth for us to use inside 80 00:03:01,423 --> 00:03:03,960 of that 2.4-gigahertz network. 81 00:03:03,960 --> 00:03:06,780 So when we split this up into 11 channels or more, 82 00:03:06,780 --> 00:03:07,753 there's bound to be some overlap 83 00:03:07,753 --> 00:03:10,980 because each channel is going to cover 22 megahertz 84 00:03:10,980 --> 00:03:12,510 out of the 72 megahertz 85 00:03:12,510 --> 00:03:14,760 that the government regulators gave us for our use. 86 00:03:14,760 --> 00:03:16,770 In fact, there are only really three channels 87 00:03:16,770 --> 00:03:20,040 that don't overlap inside the 2.4-gigahertz band, 88 00:03:20,040 --> 00:03:23,490 and these are channel one, channel six, and channel 11. 89 00:03:23,490 --> 00:03:25,290 This is something you definitely want to memorize 90 00:03:25,290 --> 00:03:26,490 for the exam. 91 00:03:26,490 --> 00:03:28,350 If you're using a frequency band 92 00:03:28,350 --> 00:03:30,600 inside the 2.4-gigahertz band, 93 00:03:30,600 --> 00:03:33,150 you should always choose channels one, six 94 00:03:33,150 --> 00:03:35,610 and 11 to avoid any kind of interference 95 00:03:35,610 --> 00:03:37,440 because these do not overlap, 96 00:03:37,440 --> 00:03:39,870 where all the other channels inside will overlap 97 00:03:39,870 --> 00:03:41,280 to some degree. 98 00:03:41,280 --> 00:03:42,583 Now, which channels you can utilize inside 99 00:03:42,583 --> 00:03:45,990 of your 802.11 network is also going to be determined 100 00:03:45,990 --> 00:03:48,210 by your local government's regulations. 101 00:03:48,210 --> 00:03:50,820 Here in the United States, we only have channels one 102 00:03:50,820 --> 00:03:52,320 through 11 for our use. 103 00:03:52,320 --> 00:03:53,700 The same holds true in Canada 104 00:03:53,700 --> 00:03:55,650 and other places in North America. 105 00:03:55,650 --> 00:03:57,972 But if you live in Japan, you actually have channels one 106 00:03:57,972 --> 00:03:59,940 through 14 for your use. 107 00:03:59,940 --> 00:04:01,590 If you live anywhere else in the world, 108 00:04:01,590 --> 00:04:03,990 you can pretty much use channels one through 13, 109 00:04:03,990 --> 00:04:07,110 but again, check your local government regulations first. 110 00:04:07,110 --> 00:04:08,730 Now, because of all the overlapping 111 00:04:08,730 --> 00:04:10,200 and interference that was being caused 112 00:04:10,200 --> 00:04:11,910 by this smaller channel size, 113 00:04:11,910 --> 00:04:13,920 where we have these 22 megahertz channels 114 00:04:13,920 --> 00:04:15,720 all competing for usage, 115 00:04:15,720 --> 00:04:18,476 the newer standards inside the 802.11 wireless system began 116 00:04:18,476 --> 00:04:21,149 to operate inside of a new frequency band, 117 00:04:21,149 --> 00:04:23,520 known as the 5-gigahertz band. 118 00:04:23,520 --> 00:04:26,220 Now, the 5-gigahertz frequency band contains frequencies 119 00:04:26,220 --> 00:04:31,220 from around 5.725 gigahertz, up to 5.875 gigahertz, 120 00:04:31,560 --> 00:04:34,800 and we simply refer to this as the 5-gigahertz band. 121 00:04:34,800 --> 00:04:36,990 Now, due to the larger frequency band allocated 122 00:04:36,990 --> 00:04:39,210 by the government within this 5-gigahertz spectrum 123 00:04:39,210 --> 00:04:41,490 for our wireless networks, we can actually use up 124 00:04:41,490 --> 00:04:45,300 to 24 nonoverlapping channels of 20 megahertz per channel, 125 00:04:45,300 --> 00:04:47,550 when we're working in a 5-gigahertz-based, 126 00:04:47,550 --> 00:04:49,830 802.11 wireless network. 127 00:04:49,830 --> 00:04:52,050 The use of these nonoverlapping channels allows 128 00:04:52,050 --> 00:04:54,900 for less interference and higher levels of performance. 129 00:04:54,900 --> 00:04:57,480 The 5-gigahertz band is preferred for applications 130 00:04:57,480 --> 00:04:59,310 that require higher data throughput, 131 00:04:59,310 --> 00:05:01,170 such as video streaming and gaming. 132 00:05:01,170 --> 00:05:02,730 But it does have a shorter range than 133 00:05:02,730 --> 00:05:04,950 our 2.4-gigahertz band networks do, 134 00:05:04,950 --> 00:05:06,570 and it doesn't penetrate solid objects as well 135 00:05:06,570 --> 00:05:10,110 as the 2.4-gigahertz frequencies do, either. 136 00:05:10,110 --> 00:05:11,880 In addition to using the default channel width 137 00:05:11,880 --> 00:05:14,400 of 20 megahertz within the 5-gigahertz band, 138 00:05:14,400 --> 00:05:16,800 we can also use something known as channel bonding 139 00:05:16,800 --> 00:05:18,484 to create wider channels by merging two 140 00:05:18,484 --> 00:05:20,520 or more of these neighboring channels 141 00:05:20,520 --> 00:05:23,340 into a single wider channel for our data use. 142 00:05:23,340 --> 00:05:24,913 For example, instead of simply using one 143 00:05:24,913 --> 00:05:27,840 of our 20-megahertz channels to transmit our data, 144 00:05:27,840 --> 00:05:29,580 we can instead perform channel bonding 145 00:05:29,580 --> 00:05:32,460 across two channels to provide us with double the bandwidth 146 00:05:32,460 --> 00:05:34,830 because now we have 40 megahertz to work with 147 00:05:34,830 --> 00:05:36,510 instead of 20 megahertz. 148 00:05:36,510 --> 00:05:39,420 In fact, we actually can bond up to eight channels together 149 00:05:39,420 --> 00:05:41,850 inside the 5-gigahertz spectrum to create a 150 00:05:41,850 --> 00:05:45,540 virtual channel that is 160 megahertz in width. 151 00:05:45,540 --> 00:05:47,700 Now, channel bonding is great for increasing the speed 152 00:05:47,700 --> 00:05:50,340 of your wireless network, but you have to be aware 153 00:05:50,340 --> 00:05:52,410 that it does have a potential downside, 154 00:05:52,410 --> 00:05:54,150 because when you use channel bonding, 155 00:05:54,150 --> 00:05:56,040 this can lead to increased channel widths, 156 00:05:56,040 --> 00:05:57,030 like we just said, 157 00:05:57,030 --> 00:05:59,040 and these increased channel widths are more susceptible 158 00:05:59,040 --> 00:06:01,200 to interference because you're reducing the number 159 00:06:01,200 --> 00:06:04,680 of nonoverlapping channels down from 24 to 12, 160 00:06:04,680 --> 00:06:06,720 and then down to six, and then down to three, 161 00:06:06,720 --> 00:06:08,760 and so on depending on how many channels 162 00:06:08,760 --> 00:06:10,680 you decide to bond together. 163 00:06:10,680 --> 00:06:11,590 Now, the newest frequency band 164 00:06:11,590 --> 00:06:13,650 that's used in wireless networking is 165 00:06:13,650 --> 00:06:15,660 actually the 6-gigahertz band. 166 00:06:15,660 --> 00:06:17,430 The 6-gigahertz frequency band is a 167 00:06:17,430 --> 00:06:19,350 relatively new spectrum that was opened up 168 00:06:19,350 --> 00:06:21,840 for Wi-Fi use that offers us even more channels 169 00:06:21,840 --> 00:06:24,390 and bandwidth that allows us to have faster connections 170 00:06:24,390 --> 00:06:26,100 and less congestion. 171 00:06:26,100 --> 00:06:28,950 This 6-gigahertz band is ideal for high density areas 172 00:06:28,950 --> 00:06:31,080 and applications that demand higher speed, 173 00:06:31,080 --> 00:06:32,700 wireless communications. 174 00:06:32,700 --> 00:06:35,250 This 6-gigahertz frequency band contains frequencies 175 00:06:35,250 --> 00:06:38,040 starting at around 5.925 gigahertz, 176 00:06:38,040 --> 00:06:41,010 and goes all the way up to 7.125 gigahertz. 177 00:06:41,010 --> 00:06:44,310 But we still refer to this simply as the 6-gigahertz band. 178 00:06:44,310 --> 00:06:46,710 Now, you may notice that the 6-gigahertz band has the 179 00:06:46,710 --> 00:06:49,410 larger amount of spectrum assigned to it by the government 180 00:06:49,410 --> 00:06:52,290 because we now have 1200 megahertz allocated 181 00:06:52,290 --> 00:06:54,930 to the 6-gigahertz frequency band for use with Wi-Fi 182 00:06:54,930 --> 00:06:56,520 and wireless networking. 183 00:06:56,520 --> 00:07:00,300 Each channel inside this range can either be 20, 40, 80, 184 00:07:00,300 --> 00:07:03,390 or 160 megahertz in size, allowing for as many 185 00:07:03,390 --> 00:07:06,360 as 59 channels when using the 20 megahertz channel width, 186 00:07:06,360 --> 00:07:07,590 and as few as seven channels 187 00:07:07,590 --> 00:07:10,470 when using the 160 megahertz channel width. 188 00:07:10,470 --> 00:07:12,174 Now, the final thing I want to mention is the impacts 189 00:07:12,174 --> 00:07:15,060 of government regulation on our use of wireless frequencies 190 00:07:15,060 --> 00:07:16,560 inside of our networks. 191 00:07:16,560 --> 00:07:18,500 We already discussed how the government allocates portions 192 00:07:18,500 --> 00:07:20,940 of the wireless spectrum for our use inside 193 00:07:20,940 --> 00:07:22,912 of our wireless networks, including small portions 194 00:07:22,912 --> 00:07:25,560 of the 2.4-gigahertz, 5-gigahertz, 195 00:07:25,560 --> 00:07:27,810 and 6-gigahertz frequency bands. 196 00:07:27,810 --> 00:07:30,060 When 802.11a was first introduced 197 00:07:30,060 --> 00:07:31,230 for wireless networking, 198 00:07:31,230 --> 00:07:33,930 it actually used the 5-gigahertz frequency band, 199 00:07:33,930 --> 00:07:35,460 but this was actually causing some issues 200 00:07:35,460 --> 00:07:37,814 with other devices that were already using frequencies close 201 00:07:37,814 --> 00:07:40,560 to that band, like military radar systems 202 00:07:40,560 --> 00:07:42,570 and some types of medical devices. 203 00:07:42,570 --> 00:07:46,530 So in response to this, the 802.11h standard was developed, 204 00:07:46,530 --> 00:07:48,840 and this was done to comply with European regulations 205 00:07:48,840 --> 00:07:50,550 for wireless networking initially, 206 00:07:50,550 --> 00:07:52,800 but its principles have now been widely adopted 207 00:07:52,800 --> 00:07:54,510 in various regions around the globe 208 00:07:54,510 --> 00:07:55,770 because they were very effective 209 00:07:55,770 --> 00:07:57,810 in managing interference and optimizing the 210 00:07:57,810 --> 00:08:00,390 overall use of the 5-gigahertz frequency band. 211 00:08:00,390 --> 00:08:04,140 This 802.11h standard includes some key features, 212 00:08:04,140 --> 00:08:07,650 like dynamic frequency selection and transmit power control. 213 00:08:07,650 --> 00:08:10,020 Dynamic frequency selection, or DFS, 214 00:08:10,020 --> 00:08:11,520 is a feature that requires devices 215 00:08:11,520 --> 00:08:14,370 to actively monitor the environment for radar signals. 216 00:08:14,370 --> 00:08:16,140 If such signals are being detected, 217 00:08:16,140 --> 00:08:18,030 the devices will then switch to another channel 218 00:08:18,030 --> 00:08:20,760 to avoid interfering with those radar systems. 219 00:08:20,760 --> 00:08:23,490 Now, transmit power control, or TPC, 220 00:08:23,490 --> 00:08:25,740 allows your devices to adjust their transmitting power 221 00:08:25,740 --> 00:08:27,390 to the minimum required for maintaining a 222 00:08:27,390 --> 00:08:29,040 good quality connection. 223 00:08:29,040 --> 00:08:31,020 This helps to reduce interference with other devices 224 00:08:31,020 --> 00:08:33,840 and services and also minimizes power consumption, 225 00:08:33,840 --> 00:08:35,370 which can be particularly beneficial 226 00:08:35,370 --> 00:08:38,280 if you're using a battery operated network device. 227 00:08:38,280 --> 00:08:39,986 The last thing we need to cover in this lesson is 228 00:08:39,986 --> 00:08:42,630 something known as band steering. 229 00:08:42,630 --> 00:08:44,220 Now, band steering is a technology 230 00:08:44,220 --> 00:08:45,810 that's used in wireless networking 231 00:08:45,810 --> 00:08:48,420 that optimizes the distribution of your client devices 232 00:08:48,420 --> 00:08:50,220 across different frequency bands. 233 00:08:50,220 --> 00:08:52,830 Typically, this is going to be across the 2.4-gigahertz 234 00:08:52,830 --> 00:08:54,690 and 5-gigahertz bands. 235 00:08:54,690 --> 00:08:56,970 The band steering feature is particularly relevant 236 00:08:56,970 --> 00:08:58,560 for environments where two or more 237 00:08:58,560 --> 00:09:00,540 frequency bands are being utilized 238 00:09:00,540 --> 00:09:02,610 by your equipment and your clients. 239 00:09:02,610 --> 00:09:04,980 Band steering works by detecting your client devices 240 00:09:04,980 --> 00:09:07,170 that are capable of operating on the less congested 241 00:09:07,170 --> 00:09:10,920 and faster bands, like the 5-gigahertz or 6-gigahertz bands, 242 00:09:10,920 --> 00:09:12,570 and then steering them over to that, 243 00:09:12,570 --> 00:09:15,330 leaving the more-crowded 2.4-gigahertz bands 244 00:09:15,330 --> 00:09:18,240 for client devices that only support that frequency. 245 00:09:18,240 --> 00:09:19,890 This can result in a more efficient use 246 00:09:19,890 --> 00:09:21,540 of the available spectral bandwidth, 247 00:09:21,540 --> 00:09:23,220 which reduces interference and improves 248 00:09:23,220 --> 00:09:24,930 your overall network performance, 249 00:09:24,930 --> 00:09:26,670 especially in scenarios where a large number 250 00:09:26,670 --> 00:09:29,550 of devices are going to be present on that network. 251 00:09:29,550 --> 00:09:31,290 This is an intelligent management tool 252 00:09:31,290 --> 00:09:33,510 that helps to enhance our Wi-Fi user experience 253 00:09:33,510 --> 00:09:35,730 by automatically allocating bandwidth resources 254 00:09:35,730 --> 00:09:37,500 in a dual-band wireless environment 255 00:09:37,500 --> 00:09:39,270 to the clients that need it most. 256 00:09:39,270 --> 00:09:41,730 So remember, there are three different frequency bands 257 00:09:41,730 --> 00:09:44,550 that are used for wireless networks, 2.4-gigahertz, 258 00:09:44,550 --> 00:09:46,830 5-gigahertz, and 6-gigahertz. 259 00:09:46,830 --> 00:09:48,750 Each of these has their own characteristics in terms 260 00:09:48,750 --> 00:09:50,610 of data transfer speeds, and the distance 261 00:09:50,610 --> 00:09:52,440 that they can provide coverage for. 262 00:09:52,440 --> 00:09:55,110 When you're dealing with the older 2.4-gigahertz band, 263 00:09:55,110 --> 00:09:57,240 you're going to have the slowest data transfer speeds, 264 00:09:57,240 --> 00:09:58,740 due to having smaller channel widths 265 00:09:58,740 --> 00:10:00,690 and fewer nonoverlapping channels, 266 00:10:00,690 --> 00:10:02,946 which can lead to interference and retransmissions 267 00:10:02,946 --> 00:10:03,980 of your data. 268 00:10:03,980 --> 00:10:06,450 On the other hand, the 2.4-gigahertz band 269 00:10:06,450 --> 00:10:07,950 does provide the greatest distance 270 00:10:07,950 --> 00:10:09,630 in terms of your wireless coverage. 271 00:10:09,630 --> 00:10:13,020 So there is a trade-off here of speed versus distance. 272 00:10:13,020 --> 00:10:15,342 Now, the five-gigahertz band has faster data transfer speeds 273 00:10:15,342 --> 00:10:17,610 than the 2.4-gigahertz band 274 00:10:17,610 --> 00:10:19,320 because it uses a higher frequency 275 00:10:19,320 --> 00:10:21,810 and can support wider channels through channel bonding 276 00:10:21,810 --> 00:10:25,380 by using either 20, 40, 80, or 160 megahertz 277 00:10:25,380 --> 00:10:26,700 in width channels. 278 00:10:26,700 --> 00:10:28,650 This does increase the data transfer speeds, 279 00:10:28,650 --> 00:10:31,050 but unfortunately, it does come at a cost 280 00:10:31,050 --> 00:10:33,150 because 5-gigahertz band frequencies 281 00:10:33,150 --> 00:10:35,010 do provide shorter distances than 282 00:10:35,010 --> 00:10:37,590 their 2.4-gigahertz band equivalents. 283 00:10:37,590 --> 00:10:39,840 Now, the 6-gigahertz band is actually the fastest 284 00:10:39,840 --> 00:10:42,270 of all three frequency bands that we've discussed, 285 00:10:42,270 --> 00:10:43,872 but this is because it uses a higher frequency 286 00:10:43,872 --> 00:10:47,520 and supports channel widths of 20, 40, 80 287 00:10:47,520 --> 00:10:50,100 and 160 megahertz in width. 288 00:10:50,100 --> 00:10:51,720 Of the three frequencies that we've discussed 289 00:10:51,720 --> 00:10:52,710 in this lesson though, 290 00:10:52,710 --> 00:10:55,102 the 6-gigahertz band does provide the shortest distances 291 00:10:55,102 --> 00:10:57,240 for its coverage, and it does offer the 292 00:10:57,240 --> 00:11:00,423 least amount of solid object penetration for our use cases.