WEBVTT 0:00:03.060000 --> 0:00:08.020000 Hello and welcome to this video titled Power over Ethernet. 0:00:08.020000 --> 0:00:12.760000 In this video I'm going to cover what is power over Ethernet and why do 0:00:12.760000 --> 0:00:17.280000 we need it? What types of things can be powered with this technology? 0:00:17.280000 --> 0:00:20.560000 What are some of the benefits of power over Ethernet? 0:00:20.560000 --> 0:00:25.860000 These acronyms of PSE and PD will define what they mean. 0:00:25.860000 --> 0:00:31.780000 We'll talk about how much power can be sent with power over Ethernet standards. 0:00:31.780000 --> 0:00:35.500000 How exactly is the power delivered? 0:00:35.500000 --> 0:00:37.700000 Detection and negotiation. 0:00:37.700000 --> 0:00:41.300000 How does a power over Ethernet device know that what it's connected to 0:00:41.300000 --> 0:00:43.740000 even needs power in the first place? 0:00:43.740000 --> 0:00:47.620000 And we'll look at some power over Ethernet monitoring techniques, specifically 0:00:47.620000 --> 0:00:52.720000 using a couple of Cisco specific iOS commands. 0:00:52.720000 --> 0:00:56.580000 So let's start with why do we need power over Ethernet? 0:00:56.580000 --> 0:00:58.820000 Well, let's take a step back here for a second. 0:00:58.820000 --> 0:01:00.680000 What is power over Ethernet? 0:01:00.680000 --> 0:01:06.260000 Like the term sounds, it's this idea of running an Ethernet cable to something. 0:01:06.260000 --> 0:01:10.260000 And normally we think of an Ethernet cable as having the data go back 0:01:10.260000 --> 0:01:11.540000 and forth on that cable. 0:01:11.540000 --> 0:01:14.060000 And whatever that thing is, it's connected to the Ethernet cable, whether 0:01:14.060000 --> 0:01:20.140000 it be a laptop, a PC, an IP phone would have a separate AC connector to 0:01:20.140000 --> 0:01:21.500000 power that device. 0:01:21.500000 --> 0:01:24.760000 Well, power over Ethernet says, hey, let's get rid of the AC connector 0:01:24.760000 --> 0:01:29.380000 and run power over the same Ethernet cable that's being used to deliver 0:01:29.380000 --> 0:01:34.700000 our data. We know that all host devices that connect to a network require 0:01:34.700000 --> 0:01:36.200000 some kind of a power. 0:01:36.200000 --> 0:01:42.480000 Laptops, PCs, printers, IP phones, Internet of Things devices like your 0:01:42.480000 --> 0:01:46.080000 IP cameras and your thermostats and things of that nature. 0:01:46.080000 --> 0:01:50.520000 Well, all these things need power and if they aren't battery driven, they're 0:01:50.520000 --> 0:01:54.000000 going to be driven basically by plugging into an AC outlet. 0:01:54.000000 --> 0:01:58.440000 And sometimes, due to the placement of where you want this thing to be, 0:01:58.440000 --> 0:02:02.480000 finding a close and available AC outlet to run a power cord to this thing 0:02:02.480000 --> 0:02:06.120000 isn't feasible or practical. 0:02:06.120000 --> 0:02:11.480000 So for this reason, power over Ethernet gives us a practical, useful alternative 0:02:11.480000 --> 0:02:16.120000 way to run power to that device over the same cable that's being used 0:02:16.120000 --> 0:02:17.640000 to transmit the data. 0:02:17.640000 --> 0:02:22.220000 So essentially, we're going from this, where we have a variety of devices 0:02:22.220000 --> 0:02:23.980000 that have two cables. 0:02:23.980000 --> 0:02:27.320000 The black cable represents your network data cable that's going to the 0:02:27.320000 --> 0:02:31.160000 switch. And then you have the red line here, which represents your AC 0:02:31.160000 --> 0:02:33.140000 power that's being used to power the device. 0:02:33.140000 --> 0:02:38.380000 We're going from that to this, where the one cable's being used to transmit 0:02:38.380000 --> 0:02:43.100000 both things. So I think you can start to see the benefits here of power 0:02:43.100000 --> 0:02:47.040000 over Ethernet. Certainly, there's a time and cost savings. 0:02:47.040000 --> 0:02:51.900000 We have to run less cables around walls, around cabinets, into the ceiling 0:02:51.900000 --> 0:02:54.520000 and so on and so forth. 0:02:54.520000 --> 0:02:58.780000 So not only is there less cost, because there's less cables we got to 0:02:58.780000 --> 0:03:04.300000 deal with purchasing, less AC adapters we have to worry about purchasing, 0:03:04.300000 --> 0:03:07.380000 but there's also cost savings from time, right? 0:03:07.380000 --> 0:03:11.720000 How long does it take to string one cable up into the wall, up into the 0:03:11.720000 --> 0:03:16.140000 ceiling versus two cables, or multiple cables? 0:03:16.140000 --> 0:03:17.880000 There's also flexibility. 0:03:17.880000 --> 0:03:21.500000 Basically, it boils down to, hey, if you can run an Ethernet cable to 0:03:21.500000 --> 0:03:26.240000 that location, you can put a power over Ethernet device at that location. 0:03:26.240000 --> 0:03:32.140000 Safety. Power over Ethernet, the delivery of the power is intelligent 0:03:32.140000 --> 0:03:36.320000 and designed to protect the network equipment from overload under powering 0:03:36.320000 --> 0:03:37.920000 or incorrect installation. 0:03:37.920000 --> 0:03:41.520000 So the idea with power over Ethernet is that the device providing the 0:03:41.520000 --> 0:03:45.620000 power will not only detect if the device at the other end of the cable 0:03:45.620000 --> 0:03:50.320000 needs power, but just how much power is needed so we don't overload or 0:03:50.320000 --> 0:03:52.020000 burn out that device. 0:03:52.020000 --> 0:03:56.640000 Also from a safety perspective, how often have you been traveling maybe 0:03:56.640000 --> 0:03:59.660000 internationally and used an international power adapter? 0:03:59.660000 --> 0:04:02.300000 Man, that thing got hot after a while, right? 0:04:02.300000 --> 0:04:06.140000 When you touched it to unplug it from the wall, it was pretty toasty. 0:04:06.140000 --> 0:04:10.160000 Well, sometimes those things can catch fire from a power standpoint. 0:04:10.160000 --> 0:04:13.980000 Hey, if my Ethernet cable is running the power, it's a lot safer than 0:04:13.980000 --> 0:04:17.700000 a mishmash of different power adapters I have based on where this device 0:04:17.700000 --> 0:04:22.040000 is going to be. And reliability. 0:04:22.040000 --> 0:04:25.820000 The power that's coming is coming from a central and universally compatible 0:04:25.820000 --> 0:04:29.620000 source. Going right back to that same analogy I had again. 0:04:29.620000 --> 0:04:39.360000 If you have a device, take your pick, an IP camera or think of some small 0:04:39.360000 --> 0:04:43.880000 Internet of Thing device that you're going to connect to the network. 0:04:43.880000 --> 0:04:48.560000 Now imagine if that device right now is with you and you are in the United 0:04:48.560000 --> 0:04:53.200000 States, well, you're going to have a certain type of AC adapter or jack 0:04:53.200000 --> 0:04:56.620000 or connector. You're going to have to plug into that thing to plug into 0:04:56.620000 --> 0:05:00.320000 the wall jack. If you take that same device with you on a plane and you 0:05:00.320000 --> 0:05:05.020000 go to Europe or South America or Africa, they have completely different 0:05:05.020000 --> 0:05:07.120000 wall jacks with completely different plugs. 0:05:07.120000 --> 0:05:09.940000 So there's not going to be any standardization here. 0:05:09.940000 --> 0:05:11.840000 It's not going to be reliable. 0:05:11.840000 --> 0:05:16.660000 Whereas that same thing, if it's power via Ethernet, Ethernet is used 0:05:16.660000 --> 0:05:19.380000 all across the world, all across the world that use standard Ethernet 0:05:19.380000 --> 0:05:21.920000 cables with RJ45 jacks. 0:05:21.920000 --> 0:05:25.160000 So whether that device is being powered in Africa, Europe or the United 0:05:25.160000 --> 0:05:32.560000 States, it's receiving that power on a standard RJ45 connection. 0:05:32.560000 --> 0:05:33.520000 Also scalability. 0:05:33.520000 --> 0:05:36.520000 Scalability. So if we go back to that previous picture that we just looked 0:05:36.520000 --> 0:05:37.920000 at, look at this. 0:05:37.920000 --> 0:05:41.840000 So in this situation here on the left with just those three things, I 0:05:41.840000 --> 0:05:43.540000 need three power adapters. 0:05:43.540000 --> 0:05:48.100000 Or I should say three wall jacks that they can plug into. 0:05:48.100000 --> 0:05:58.420000 So what if I've got 30 things or 300 things? 0:05:58.420000 --> 0:06:01.720000 So I'm going to say that power bricks is not very scalable. 0:06:01.720000 --> 0:06:04.960000 Whereas once again, I could have a switch, a 48 port switch. 0:06:04.960000 --> 0:06:08.280000 And if all 40 of those ports are capable of supplying power, that's like 0:06:08.280000 --> 0:06:12.900000 48 wall jacks all condensed into one box, which now the cables can be 0:06:12.900000 --> 0:06:17.340000 run out 100 meters in any given direction and provide power to whatever 0:06:17.340000 --> 0:06:21.400000 is connected to it. 0:06:21.400000 --> 0:06:26.240000 All right, so let's talk about a couple of terms here, PSD and PD. 0:06:26.240000 --> 0:06:28.360000 If you're going to deal with power over Ethernet, you have to know what 0:06:28.360000 --> 0:06:30.260000 these stand for. 0:06:30.260000 --> 0:06:33.040000 So power over Ethernet, there are a variety of standards for it. 0:06:33.040000 --> 0:06:35.400000 They have evolved over time. 0:06:35.400000 --> 0:06:42.460000 So there's 802.3 AF, AT and the latest, which is 802.3 BT, which is standardized 0:06:42.460000 --> 0:06:49.340000 in mid 2018. And all of these categorize power over Ethernet devices is 0:06:49.340000 --> 0:06:51.760000 belonging to one of two categories. 0:06:51.760000 --> 0:06:54.740000 You've got the power sourcing equipment. 0:06:54.740000 --> 0:06:58.740000 So like it sounds, that would be your device that's pushing power down 0:06:58.740000 --> 0:07:02.420000 the wire. This would typically be a network switch, which would be your 0:07:02.420000 --> 0:07:04.680000 power sourcing equipment or your PSE. 0:07:04.680000 --> 0:07:08.320000 And then you have at the other end of that cable, a PD, a power device, 0:07:08.320000 --> 0:07:13.940000 such as your wireless access point, or your IP phone, or your IP, or your 0:07:13.940000 --> 0:07:16.280000 IP, or your IP. So you have to have a USB camera or something like that. 0:07:16.280000 --> 0:07:22.340000 So PSEs are typically network switches, or they could be power injectors. 0:07:22.340000 --> 0:07:25.900000 So for example, here's an example of a couple of power injectors. 0:07:25.900000 --> 0:07:30.180000 Now, notice that the power injectors themselves, like these two pictures 0:07:30.180000 --> 0:07:33.520000 right here, they plug into wall outlet, don't they? 0:07:33.520000 --> 0:07:36.800000 Don't they? Both of them have plugs that plug into wall outlet. 0:07:36.800000 --> 0:07:40.020000 So when would you use something like that? 0:07:40.020000 --> 0:07:45.120000 Well, this would be a case of something where maybe I have a switch that 0:07:45.120000 --> 0:07:48.020000 does not provide power over Ethernet. 0:07:48.020000 --> 0:07:51.200000 The switch I bought doesn't provide that, or maybe I've maxed it out and 0:07:51.200000 --> 0:07:52.740000 I've got a few more ports. 0:07:52.740000 --> 0:07:55.760000 So I've got some ports that provide power over Ethernet, but those are 0:07:55.760000 --> 0:07:59.440000 all used up. I have other ports left on that switch that I can plug things 0:07:59.440000 --> 0:08:01.700000 into, but those are not powered ports. 0:08:01.700000 --> 0:08:03.140000 They don't supply power. 0:08:03.140000 --> 0:08:06.860000 Either way, I can't run power down the cable, and what if the other side 0:08:06.860000 --> 0:08:14.540000 of the cable is not something that supports what if we had an Internet 0:08:14.540000 --> 0:08:19.580000 of Thing device that doesn't plug in, something that relies on power over 0:08:19.580000 --> 0:08:22.860000 Ethernet, where the only way you could power that thing is if you plug 0:08:22.860000 --> 0:08:24.160000 an Ethernet cable into it. 0:08:24.160000 --> 0:08:27.580000 It doesn't even have jacks where you could plug it into a wall or something 0:08:27.580000 --> 0:08:29.760000 like that. Well, now I have an incompatibility. 0:08:29.760000 --> 0:08:35.880000 I have a powered device without any AC capability, and yet I've got a 0:08:35.880000 --> 0:08:39.460000 switch which can't send power to that device. 0:08:39.460000 --> 0:08:41.800000 That's where you'd use something like this power injector here. 0:08:41.800000 --> 0:08:54.040000 The switch would have an Ethernet cable that runs down to the power injector. 0:08:54.040000 --> 0:08:58.960000 And that would lead down to the power device. 0:08:58.960000 --> 0:09:03.980000 So how much power can you get from power over Ethernet? 0:09:03.980000 --> 0:09:07.920000 Well, as I mentioned, the standards have evolved over time. 0:09:07.920000 --> 0:09:14.640000 So the original standard 802.3 AF supplied up to 15.4 watts for the power 0:09:14.640000 --> 0:09:21.140000 device, and the latest standards, which is 802.3 BT, which also goes by 0:09:21.140000 --> 0:09:24.020000 the name of UPOE plus that's 7.0. 0:09:24.020000 --> 0:09:29.840000 And the Cisco's proprietary way of implementing 802.3 BT can supply up 0:09:29.840000 --> 0:09:33.060000 to 90 to 95 watts per power device. 0:09:33.060000 --> 0:09:37.760000 Now one thing to know about these numbers here in this chart under the 0:09:37.760000 --> 0:09:43.280000 power budget per device is that those numbers there are how much power 0:09:43.280000 --> 0:09:46.380000 is leaving the port on the switch. 0:09:46.380000 --> 0:09:50.120000 But not all of that power is going to get down to the power device at 0:09:50.120000 --> 0:09:54.760000 the other end. Some of it is going to dissipate as like heat or electrical 0:09:54.760000 --> 0:09:57.400000 resistance within the cabling itself. 0:09:57.400000 --> 0:10:01.920000 So most of it reaches the power device, but not all of it. 0:10:01.920000 --> 0:10:03.440000 So just be aware of that. 0:10:03.440000 --> 0:10:08.480000 Also one thing to mention here, notice how it says power budget. 0:10:08.480000 --> 0:10:09.940000 Actually there's a little bit of a spelling there. 0:10:09.940000 --> 0:10:13.160000 It says budge, but it should say power budget per device. 0:10:13.160000 --> 0:10:15.940000 You should know what that term power budget means. 0:10:15.940000 --> 0:10:20.980000 So when you buy a switch that's a power over ethernet capable switch, 0:10:20.980000 --> 0:10:25.600000 they might say, hey the power budget of the switch is 540 watts. 0:10:25.600000 --> 0:10:29.340000 So what they're talking about is that's the maximum power it can deliver 0:10:29.340000 --> 0:10:31.940000 to the power devices. 0:10:31.940000 --> 0:10:36.780000 Now that power might be spread out over all the ports in the switch, or 0:10:36.780000 --> 0:10:41.140000 depending on what you're powering up, after you use like 10 or 15 ports, 0:10:41.140000 --> 0:10:43.740000 maybe your entire power budget. 0:10:43.740000 --> 0:10:47.900000 And you don't have any power left to deliver to some of the other ports. 0:10:47.900000 --> 0:10:50.420000 So you'll hear that term power budget. 0:10:50.420000 --> 0:10:51.240000 And that's what that means. 0:10:51.240000 --> 0:10:56.200000 The total power available for a power sourcing equipment to send down 0:10:56.200000 --> 0:11:00.760000 to its total quantity of powered devices. 0:11:00.760000 --> 0:11:03.040000 So how is the power delivered? 0:11:03.040000 --> 0:11:05.680000 Well, it really depends on the standard that we're dealing with. 0:11:05.680000 --> 0:11:11.280000 We know the ethernet cables are eight wires total, so we call this unshielded 0:11:11.280000 --> 0:11:16.900000 twisted pair. So here you can see each one of these things here. 0:11:16.900000 --> 0:11:21.260000 So like right there, that's a pair of wires. 0:11:21.260000 --> 0:11:26.360000 Right, we've got a white wire and a sort of lime green colored wire and 0:11:26.360000 --> 0:11:27.580000 they're twisted together. 0:11:27.580000 --> 0:11:32.260000 So this is called a twisted pair. 0:11:32.260000 --> 0:11:37.760000 And you can see if that's two, well that'd be 4, 6, 8. 0:11:37.760000 --> 0:11:41.900000 So within this one category 5E cable, there's actually eight wires in 0:11:41.900000 --> 0:11:45.180000 there which are twisted together in pairs. 0:11:45.180000 --> 0:11:49.820000 Now depending on the power over ethernet standard that you're using will 0:11:49.820000 --> 0:11:56.620000 determine how many of those pairs are actually used to transmit the power. 0:11:56.620000 --> 0:12:01.440000 So when you're talking about the earlier standards of 802.3 AF and 802 0:12:01.440000 --> 0:12:06.440000 .3 AT, those utilized two of the pairs. 0:12:06.440000 --> 0:12:10.260000 So actually two of the pairs were used just for data. 0:12:10.260000 --> 0:12:13.320000 Two other pairs were used for the power. 0:12:13.320000 --> 0:12:17.080000 So that one cable within it separated out. 0:12:17.080000 --> 0:12:19.500000 Some wires were used just to deliver the power. 0:12:19.500000 --> 0:12:21.960000 Other wires were used just to deliver the data. 0:12:21.960000 --> 0:12:26.780000 Then once they came up with the newer standards of like 802.3BT which 0:12:26.780000 --> 0:12:30.720000 Cisco does in their own sort of way called universal power over ethernet. 0:12:30.720000 --> 0:12:34.800000 Now we're talking about using all the pairs, all eight wires to carry 0:12:34.800000 --> 0:12:37.440000 both data and power. 0:12:37.440000 --> 0:12:40.340000 And it gets kind of complicated as to how it actually does that at the 0:12:40.340000 --> 0:12:43.120000 physical level but just know it works. 0:12:43.120000 --> 0:12:47.340000 It is capable of doing that. 0:12:47.340000 --> 0:12:51.060000 So the last thing I want to talk about here is when something plugs into 0:12:51.060000 --> 0:12:55.820000 an ethernet switch that's capable of delivering power over ethernet, that 0:12:55.820000 --> 0:13:00.460000 ethernet switch needs to know is the thing that just plugged into me something 0:13:00.460000 --> 0:13:02.260000 that needs my power? 0:13:02.260000 --> 0:13:05.720000 Like maybe what plugged into me is a laptop that has his own separate 0:13:05.720000 --> 0:13:08.560000 AC connector. I don't need to send power to that device. 0:13:08.560000 --> 0:13:10.380000 It's being powered separately. 0:13:10.380000 --> 0:13:13.720000 Or maybe what just plugged into me is an IP phone. 0:13:13.720000 --> 0:13:15.760000 And that thing needs me to power it up. 0:13:15.760000 --> 0:13:17.600000 Well, how's it know? 0:13:17.600000 --> 0:13:20.260000 And we're going to talk at a real high level here just for a minute on 0:13:20.260000 --> 0:13:23.400000 how that detection process takes place. 0:13:23.400000 --> 0:13:28.140000 So when power over ethernet is enabled on a port, here's what happens. 0:13:28.140000 --> 0:13:32.040000 First of all we need to know, are we connected to a power device or not? 0:13:32.040000 --> 0:13:35.320000 And if so, how much power does it need? 0:13:35.320000 --> 0:13:39.660000 Because remember we can go from 15.4 watts all the way up to like 90 watts 0:13:39.660000 --> 0:13:42.220000 depending on which standard we're dealing with. 0:13:42.220000 --> 0:13:45.200000 So here's a summary of the initial steps we're going to go through. 0:13:45.200000 --> 0:13:49.460000 Number one, the power sourcing equipment, i.e. 0:13:49.460000 --> 0:13:54.040000 network switch, will output a small amount of power to detect if there's 0:13:54.040000 --> 0:13:56.420000 any resistance. If there's any resistance. 0:13:56.420000 --> 0:13:59.360000 So power's going to go out and it's going to see if any of that power 0:13:59.360000 --> 0:14:02.840000 comes back on a separate cable or a separate wire. 0:14:02.840000 --> 0:14:08.960000 Now if we're talking about a powered device like an IP phone or a surveillance 0:14:08.960000 --> 0:14:12.520000 camera that's an IP surveillance camera that needs power over ethernet, 0:14:12.520000 --> 0:14:16.700000 that device will have on the wire that's receiving the power, special 0:14:16.700000 --> 0:14:18.340000 resistors in it. 0:14:18.340000 --> 0:14:23.740000 So when it sort of loops the power back to the power sourcing equipment, 0:14:23.740000 --> 0:14:27.040000 it'll change it in a little way, like a little bit less power will be 0:14:27.040000 --> 0:14:30.600000 looped back than what came down from the switch. 0:14:30.600000 --> 0:14:35.300000 That's how the switch will know, okay, I'm connected to a power device. 0:14:35.300000 --> 0:14:38.780000 Because if the device I was connected to was not a power device like a 0:14:38.780000 --> 0:14:42.900000 laptop, the amount of electrical energy I sent down, which is very, very, 0:14:42.900000 --> 0:14:46.560000 very tiny. It's not enough to hurt the NIC card or hurt the device at 0:14:46.560000 --> 0:14:50.820000 all. That amount that I sent down would be reflected back to me in full. 0:14:50.820000 --> 0:14:51.640000 It wouldn't be changed. 0:14:51.640000 --> 0:14:54.360000 And so I'd know, okay, there's no resistor down there. 0:14:54.360000 --> 0:14:57.360000 There's nothing that's blocking it or reducing it. 0:14:57.360000 --> 0:15:01.840000 So therefore, whatever that device is, is not a powered device. 0:15:01.840000 --> 0:15:07.740000 But the amount of electrical energy I get back is a little bit less than 0:15:07.740000 --> 0:15:08.700000 what I sent down. 0:15:08.700000 --> 0:15:11.680000 And there's a certain ratio, can't just be some random amount less, power 0:15:11.680000 --> 0:15:15.140000 over ethernet says, okay, it's got to fall within this threshold here. 0:15:15.140000 --> 0:15:18.400000 If the amount you got back is within this threshold and those details 0:15:18.400000 --> 0:15:21.420000 are more than we need to know for this video, but if it's within this 0:15:21.420000 --> 0:15:24.320000 threshold, that is a powered device. 0:15:24.320000 --> 0:15:28.280000 Okay, so now what happens is the power source equipment will start sending 0:15:28.280000 --> 0:15:33.240000 a little bit of power just enough to sort of like bring that device up 0:15:33.240000 --> 0:15:35.820000 into like a bare bones booting state. 0:15:35.820000 --> 0:15:39.140000 And so we're going to go back and forth with this, with sending a little 0:15:39.140000 --> 0:15:41.080000 bit more power, sensing the resistance. 0:15:41.080000 --> 0:15:43.420000 Oh, now the resistance is this much. 0:15:43.420000 --> 0:15:46.620000 That tells me the power device can handle even more. 0:15:46.620000 --> 0:15:48.380000 And it'll keep going back and forth. 0:15:48.380000 --> 0:15:52.000000 And so by using this electrical energy and resistance values and thresholds, 0:15:52.000000 --> 0:15:56.020000 we'll get to the point where we know we've reached our limit. 0:15:56.020000 --> 0:15:58.340000 Now that device is good to go. 0:15:58.340000 --> 0:16:02.180000 And so now the PSC knows just how much power to deliver. 0:16:02.180000 --> 0:16:05.940000 Now, in addition to that, so this is all part of the power over ethernet 0:16:05.940000 --> 0:16:10.440000 standard. Whether you're talking about 802.3 AF or AT, it's all based 0:16:10.440000 --> 0:16:13.560000 on resistance levels and how much power we got back. 0:16:13.560000 --> 0:16:15.020000 Was there any resistance? 0:16:15.020000 --> 0:16:19.460000 That's how in the specifications you can tell what type of device you're 0:16:19.460000 --> 0:16:23.640000 connected to and how much maximum power it can take. 0:16:23.640000 --> 0:16:27.700000 But above and beyond that, a lot of devices also implement either the 0:16:27.700000 --> 0:16:31.940000 Cisco Discovery Protocol, if we're talking about Cisco devices, or the 0:16:31.940000 --> 0:16:36.460000 Link Layer Discovery Protocol, LLDP for non-Cisco devices. 0:16:36.460000 --> 0:16:38.900000 And even Cisco devices support LLDP. 0:16:38.900000 --> 0:16:44.180000 Well, if I, by using these resistance levels and everything, if I can 0:16:44.180000 --> 0:16:50.240000 power up that device to the point where it can now start sending me CDP 0:16:50.240000 --> 0:16:55.640000 messages or LLDP messages, that device, that power device can now tell 0:16:55.640000 --> 0:16:59.900000 me the power sourcing equipment even more information about itself. 0:16:59.900000 --> 0:17:02.920000 For example, it might tell me, hey, here's the range of power. 0:17:02.920000 --> 0:17:05.860000 I would prefer you to give me this maximum amount, but I can actually 0:17:05.860000 --> 0:17:08.760000 operate with this minimal route right here. 0:17:08.760000 --> 0:17:09.840000 And we can get that information. 0:17:09.840000 --> 0:17:13.440000 We can now get information about like what type of device is it. 0:17:13.440000 --> 0:17:16.400000 So we can send it other information above and beyond just basic power 0:17:16.400000 --> 0:17:21.020000 requirements. So let's just finish off here by saying, how would we monitor 0:17:21.020000 --> 0:17:23.380000 this on like Cisco devices? 0:17:23.380000 --> 0:17:27.120000 So here we have the output of show CDP neighbor detail. 0:17:27.120000 --> 0:17:29.280000 And this is on a switch. 0:17:29.280000 --> 0:17:35.300000 And we can see here down below, it says power drawn 10.25 watts. 0:17:35.300000 --> 0:17:38.580000 So this represents the maximum required power for this. 0:17:38.580000 --> 0:17:40.180000 This is an IP phone. 0:17:40.180000 --> 0:17:44.400000 So we can see this is a, it mentions up above in platform that this is 0:17:44.400000 --> 0:17:45.740000 a Cisco IP phone. 0:17:45.740000 --> 0:17:49.380000 And this Cisco IP phone has said that the maximum power will ever need 0:17:49.380000 --> 0:18:08.560000 is 10.25 watts or 10,250 milliwatts. 0:18:08.560000 --> 0:18:13.320000 So we can see that 6.3 watts with a reduced screen brightness. 0:18:13.320000 --> 0:18:16.140000 So this particular phone has reduced screen brightness. 0:18:16.140000 --> 0:18:19.860000 And if it's on that setting, it doesn't need to draw nearly as much power. 0:18:19.860000 --> 0:18:22.880000 So you can see from CDP neighbor that we've gotten that information from 0:18:22.880000 --> 0:18:25.700000 the phone via CDP messages. 0:18:25.700000 --> 0:18:30.800000 We can also do show power in line on the switch. 0:18:30.800000 --> 0:18:33.400000 This shows us a lot of useful information. 0:18:33.400000 --> 0:18:37.840000 For example, we can see here that module one, its power budget, the maximum 0:18:37.840000 --> 0:18:42.380000 amount of power it has available in that module is 420 watts. 0:18:42.380000 --> 0:18:46.060000 Very little of that has been used right now, only 22.2 watts of that has 0:18:46.060000 --> 0:18:51.180000 been used with most of it still remaining for other ports in that module. 0:18:51.180000 --> 0:18:57.500000 And we can see down here below that gigabit 101 is connected to a 7960 0:18:57.500000 --> 0:19:00.700000 phone which is currently operating under minimal power with reduced screen 0:19:00.700000 --> 0:19:04.880000 brightness. It's operating at 6.3 watts. 0:19:04.880000 --> 0:19:09.260000 And it says on the far right column, it's capable of a maximum of 15.4 0:19:09.260000 --> 0:19:16.040000 watts. So that concludes this video on our introduction to power over 0:19:16.040000 --> 0:19:17.840000 ethernet. Thank you for watching.