[Script Info]
Title: 
[Events]
Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text
Dialogue: 0,0:00:02.05,0:00:04.54,Default,,0000,0000,0000,,The role of a switch\Nis to forward traffic
Dialogue: 0,0:00:04.54,0:00:06.76,Default,,0000,0000,0000,,based on the\Ndestination MAC address
Dialogue: 0,0:00:06.76,0:00:08.96,Default,,0000,0000,0000,,inside of an ethernet frame.
Dialogue: 0,0:00:08.96,0:00:12.91,Default,,0000,0000,0000,,This means the switch needs to\Nkeep an ongoing and active list
Dialogue: 0,0:00:12.91,0:00:15.73,Default,,0000,0000,0000,,of all of the devices\Nit happens to know about
Dialogue: 0,0:00:15.73,0:00:18.85,Default,,0000,0000,0000,,based on the MAC address\Nof those devices.
Dialogue: 0,0:00:18.85,0:00:22.24,Default,,0000,0000,0000,,The switch builds this list\Nby looking at inbound traffic
Dialogue: 0,0:00:22.24,0:00:24.52,Default,,0000,0000,0000,,and examining the\Nsource MAC address,
Dialogue: 0,0:00:24.52,0:00:26.41,Default,,0000,0000,0000,,and tying that source MAC address
Dialogue: 0,0:00:26.41,0:00:28.75,Default,,0000,0000,0000,,to a specific physical interface.
Dialogue: 0,0:00:28.75,0:00:30.52,Default,,0000,0000,0000,,And for switches\Nthat are configured
Dialogue: 0,0:00:30.52,0:00:33.10,Default,,0000,0000,0000,,with spanning tree\Nprotocol, or STP,
Dialogue: 0,0:00:33.10,0:00:36.19,Default,,0000,0000,0000,,they're also responsible for\Nensuring that a loop does not
Dialogue: 0,0:00:36.19,0:00:38.88,Default,,0000,0000,0000,,occur on the switch network.
Dialogue: 0,0:00:38.88,0:00:41.46,Default,,0000,0000,0000,,The process of sending traffic\Nthrough a switch network
Dialogue: 0,0:00:41.46,0:00:43.78,Default,,0000,0000,0000,,is the same for every ethernet frame.
Dialogue: 0,0:00:43.78,0:00:45.87,Default,,0000,0000,0000,,Let's take this\Nscenario where Sam,
Dialogue: 0,0:00:45.87,0:00:48.21,Default,,0000,0000,0000,,and you can see the MAC\Naddress for Sam's device,
Dialogue: 0,0:00:48.21,0:00:51.21,Default,,0000,0000,0000,,is sending information\Nto the SGC server,
Dialogue: 0,0:00:51.21,0:00:57.24,Default,,0000,0000,0000,,and you can see the SGC server's\NMAC address is 1000:5555:5555.
Dialogue: 0,0:00:57.24,0:00:59.88,Default,,0000,0000,0000,,We have a switch in the\Nmiddle, and all of our devices
Dialogue: 0,0:00:59.88,0:01:04.20,Default,,0000,0000,0000,,are plugged into the switch,\Nincluding Sam and the SGC server.
Dialogue: 0,0:01:04.20,0:01:06.93,Default,,0000,0000,0000,,Inside of the switch\Nis a MAC address table.
Dialogue: 0,0:01:06.93,0:01:10.05,Default,,0000,0000,0000,,It lists all the MAC\Naddresses and the interfaces
Dialogue: 0,0:01:10.05,0:01:12.09,Default,,0000,0000,0000,,where those addresses are connected.
Dialogue: 0,0:01:12.09,0:01:15.57,Default,,0000,0000,0000,,When Sam sends traffic to the\Nswitch with the destination MAC
Dialogue: 0,0:01:15.57,0:01:20.16,Default,,0000,0000,0000,,address of\N1000:5555:5555, the switch
Dialogue: 0,0:01:20.16,0:01:22.41,Default,,0000,0000,0000,,looks up that address in its table,
Dialogue: 0,0:01:22.41,0:01:26.28,Default,,0000,0000,0000,,and if one matches one of the\Nentries inside of that table,
Dialogue: 0,0:01:26.28,0:01:29.82,Default,,0000,0000,0000,,it identifies the output\Ninterface for that traffic
Dialogue: 0,0:01:29.82,0:01:32.97,Default,,0000,0000,0000,,and sends it down that\Ninterface to the server
Dialogue: 0,0:01:32.97,0:01:35.13,Default,,0000,0000,0000,,that has that MAC address.
Dialogue: 0,0:01:35.13,0:01:38.80,Default,,0000,0000,0000,,If you have multiple switches,\Nit's exactly the same process,
Dialogue: 0,0:01:38.80,0:01:41.61,Default,,0000,0000,0000,,except it occurs twice,\Nonce on the first switch
Dialogue: 0,0:01:41.61,0:01:42.87,Default,,0000,0000,0000,,and once on the second.
Dialogue: 0,0:01:42.87,0:01:45.30,Default,,0000,0000,0000,,You can see this is the\Nsame configuration where
Dialogue: 0,0:01:45.30,0:01:47.98,Default,,0000,0000,0000,,Sam is communicating\Nto the SGC server,
Dialogue: 0,0:01:47.98,0:01:50.61,Default,,0000,0000,0000,,but there is a switch A\Non one side of the network,
Dialogue: 0,0:01:50.61,0:01:52.53,Default,,0000,0000,0000,,and a switch B on the other.
Dialogue: 0,0:01:52.53,0:01:55.99,Default,,0000,0000,0000,,Switch A has a MAC address table\Nspecific to the devices plugged
Dialogue: 0,0:01:55.99,0:01:59.34,Default,,0000,0000,0000,,into Switch A, and Switch B\Nhas a completely different
Dialogue: 0,0:01:59.34,0:02:01.71,Default,,0000,0000,0000,,and unique, MAC address table.
Dialogue: 0,0:02:01.71,0:02:04.95,Default,,0000,0000,0000,,Sam is going to send traffic\Nagain to the SGC server.
Dialogue: 0,0:02:04.95,0:02:10.80,Default,,0000,0000,0000,,It knows that it's sending this traffic \Nto MAC address 1000:5555:5555.
Dialogue: 0,0:02:10.80,0:02:12.96,Default,,0000,0000,0000,,As that traffic hits Switch A, Switch A
Dialogue: 0,0:02:12.96,0:02:15.03,Default,,0000,0000,0000,,refers to its own MAC address table
Dialogue: 0,0:02:15.03,0:02:18.42,Default,,0000,0000,0000,,and knows that that particular\NMAC address is located
Dialogue: 0,0:02:18.42,0:02:22.48,Default,,0000,0000,0000,,on an interface that is\Na gigabit 0/2 interface,
Dialogue: 0,0:02:22.48,0:02:25.23,Default,,0000,0000,0000,,and so it sends that\Ntraffic out that interface
Dialogue: 0,0:02:25.23,0:02:26.58,Default,,0000,0000,0000,,to the next switch.
Dialogue: 0,0:02:26.58,0:02:29.04,Default,,0000,0000,0000,,On that switch, the\Nsame lookup process
Dialogue: 0,0:02:29.04,0:02:31.80,Default,,0000,0000,0000,,occurs, where Switch B will\Nexamine the destination
Dialogue: 0,0:02:31.80,0:02:35.22,Default,,0000,0000,0000,,MAC address, determine that\Nthat MAC address is associated
Dialogue: 0,0:02:35.22,0:02:38.28,Default,,0000,0000,0000,,with the interface fast ethernet 0/5,
Dialogue: 0,0:02:38.28,0:02:42.96,Default,,0000,0000,0000,,and sends that traffic down that\Ninterface to the destination device.
Dialogue: 0,0:02:42.96,0:02:45.35,Default,,0000,0000,0000,,You can see that building \Nthat MAC address table
Dialogue: 0,0:02:45.35,0:02:46.87,Default,,0000,0000,0000,,is extremely important.
Dialogue: 0,0:02:46.87,0:02:48.90,Default,,0000,0000,0000,,If we didn't have the MAC \Naddress table, the switch
Dialogue: 0,0:02:48.90,0:02:50.97,Default,,0000,0000,0000,,would not know where to send that traffic.
Dialogue: 0,0:02:50.97,0:02:53.04,Default,,0000,0000,0000,,In order to build\Nthat table, the switch
Dialogue: 0,0:02:53.04,0:02:55.77,Default,,0000,0000,0000,,is going to examine\Nall incoming traffic
Dialogue: 0,0:02:55.77,0:02:58.59,Default,,0000,0000,0000,,and make a note of the\Nsource MAC address.
Dialogue: 0,0:02:58.59,0:03:00.75,Default,,0000,0000,0000,,It will then associate\Nthat source MAC address
Dialogue: 0,0:03:00.75,0:03:03.51,Default,,0000,0000,0000,,to a specific interface\Non the switch.
Dialogue: 0,0:03:03.51,0:03:06.72,Default,,0000,0000,0000,,So let's take a scenario where\Nwe've just powered up a switch,
Dialogue: 0,0:03:06.72,0:03:09.18,Default,,0000,0000,0000,,it has nothing in the\NMAC address table,
Dialogue: 0,0:03:09.18,0:03:11.73,Default,,0000,0000,0000,,and we're going to send\Ninformation from Sam's computer
Dialogue: 0,0:03:11.73,0:03:13.35,Default,,0000,0000,0000,,to the SGC server.
Dialogue: 0,0:03:13.35,0:03:15.66,Default,,0000,0000,0000,,Sam's going to send that\Ntraffic to the switch,
Dialogue: 0,0:03:15.66,0:03:18.93,Default,,0000,0000,0000,,the switch is going to examine\Nthe source MAC address,
Dialogue: 0,0:03:18.93,0:03:24.15,Default,,0000,0000,0000,,and in the case of Sam's\Ndevice, that's 1000:1111:1111.
Dialogue: 0,0:03:24.15,0:03:26.97,Default,,0000,0000,0000,,It will then put that MAC\Naddress into the MAC address
Dialogue: 0,0:03:26.97,0:03:29.55,Default,,0000,0000,0000,,table, and it will\Nidentify the interface
Dialogue: 0,0:03:29.55,0:03:34.44,Default,,0000,0000,0000,,where that information was received.\NIn this case, interface F0/1.
Dialogue: 0,0:03:34.44,0:03:38.02,Default,,0000,0000,0000,,That information is then\Nsent on to the SGC server,
Dialogue: 0,0:03:38.02,0:03:42.00,Default,,0000,0000,0000,,and then when the SGC server\Nresponds to that communication,
Dialogue: 0,0:03:42.00,0:03:44.49,Default,,0000,0000,0000,,it has a different\Nsource MAC address,
Dialogue: 0,0:03:44.49,0:03:47.35,Default,,0000,0000,0000,,and the process is repeated.\NExcept in this case,
Dialogue: 0,0:03:47.35,0:03:49.65,Default,,0000,0000,0000,,the switch identifies\Nthat MAC address is
Dialogue: 0,0:03:49.65,0:03:53.49,Default,,0000,0000,0000,,coming from fast ethernet 0/5.
Dialogue: 0,0:03:53.49,0:03:56.58,Default,,0000,0000,0000,,In that previous example, we \Nwere sending information to the SGC
Dialogue: 0,0:03:56.58,0:03:59.61,Default,,0000,0000,0000,,server, but the SGC \Nserver's MAC address
Dialogue: 0,0:03:59.61,0:04:01.68,Default,,0000,0000,0000,,was not yet in the switch.
Dialogue: 0,0:04:01.68,0:04:04.59,Default,,0000,0000,0000,,If the switch does not have\Nan entry for that MAC address
Dialogue: 0,0:04:04.59,0:04:07.26,Default,,0000,0000,0000,,in the table, then it\Nwill send that information
Dialogue: 0,0:04:07.26,0:04:09.42,Default,,0000,0000,0000,,to everyone on the network.
Dialogue: 0,0:04:09.42,0:04:12.00,Default,,0000,0000,0000,,For example, we'll take Sam\Nsending this information
Dialogue: 0,0:04:12.00,0:04:13.38,Default,,0000,0000,0000,,to the SGC server.
Dialogue: 0,0:04:13.38,0:04:15.54,Default,,0000,0000,0000,,You can see in this case,\Nthe MAC address table
Dialogue: 0,0:04:15.54,0:04:17.97,Default,,0000,0000,0000,,has nothing inside\Nof it at the moment.
Dialogue: 0,0:04:17.97,0:04:20.73,Default,,0000,0000,0000,,The MAC address table will be\Nupdated with the source MAC
Dialogue: 0,0:04:20.73,0:04:23.79,Default,,0000,0000,0000,,address because Sam did send\Nthat information to the switch,
Dialogue: 0,0:04:23.79,0:04:27.81,Default,,0000,0000,0000,,and it did associate that\Nwith fast ethernet 0/1,
Dialogue: 0,0:04:27.81,0:04:29.55,Default,,0000,0000,0000,,But we're sending this information
Dialogue: 0,0:04:29.55,0:04:32.37,Default,,0000,0000,0000,,to a destination MAC\Naddress that's not currently
Dialogue: 0,0:04:32.37,0:04:34.47,Default,,0000,0000,0000,,listed in the switch's table.
Dialogue: 0,0:04:34.47,0:04:38.46,Default,,0000,0000,0000,,In that case, it's going to now\Nsend that traffic to everybody
Dialogue: 0,0:04:38.46,0:04:40.65,Default,,0000,0000,0000,,on the network, and\Neffectively flood
Dialogue: 0,0:04:40.65,0:04:44.52,Default,,0000,0000,0000,,that traffic to all of the\Nother interfaces on that switch.
Dialogue: 0,0:04:44.52,0:04:47.07,Default,,0000,0000,0000,,If you're familiar with\Nthe operation of a hub,
Dialogue: 0,0:04:47.07,0:04:49.83,Default,,0000,0000,0000,,then you'll notice that this\Nis very similar to the way
Dialogue: 0,0:04:49.83,0:04:51.33,Default,,0000,0000,0000,,a hub works normally.
Dialogue: 0,0:04:51.33,0:04:53.79,Default,,0000,0000,0000,,But this traffic being\Nsent to every device
Dialogue: 0,0:04:53.79,0:04:56.52,Default,,0000,0000,0000,,ensures that at least\Nthe destination will
Dialogue: 0,0:04:56.52,0:04:58.47,Default,,0000,0000,0000,,receive this particular frame.
Dialogue: 0,0:04:58.47,0:05:02.16,Default,,0000,0000,0000,,And in this example, you can see\Nthat the SGC server did indeed
Dialogue: 0,0:05:02.16,0:05:05.28,Default,,0000,0000,0000,,receive that frame, and\Nwhen the SGC server responds
Dialogue: 0,0:05:05.28,0:05:08.28,Default,,0000,0000,0000,,back to Sam with a response,\Nthe source MAC address
Dialogue: 0,0:05:08.28,0:05:10.32,Default,,0000,0000,0000,,will be identified by the switch.
Dialogue: 0,0:05:10.32,0:05:13.38,Default,,0000,0000,0000,,That information will be added\Nto the MAC address table,
Dialogue: 0,0:05:13.38,0:05:15.83,Default,,0000,0000,0000,,and the switch will no longer \Nneed to flood the traffic
Dialogue: 0,0:05:15.83,0:05:20.01,Default,,0000,0000,0000,,across all interfaces if communication\Nis occurring between Sam
Dialogue: 0,0:05:20.01,0:05:23.27,Default,,0000,0000,0000,,and the SGC server again.
Dialogue: 0,0:05:23.27,0:05:26.75,Default,,0000,0000,0000,,On an IPv4 network,\Ndevices are able to obtain
Dialogue: 0,0:05:26.75,0:05:31.19,Default,,0000,0000,0000,,the MAC address of a remote\Ndevice using the ARP protocol.
Dialogue: 0,0:05:31.19,0:05:34.43,Default,,0000,0000,0000,,ARP stands for \NAddress Resolution Protocol.
Dialogue: 0,0:05:34.43,0:05:37.73,Default,,0000,0000,0000,,ARP will query the network\Nfor a specific IP address,
Dialogue: 0,0:05:37.73,0:05:41.66,Default,,0000,0000,0000,,and that IP address will respond\Nback with its MAC address.
Dialogue: 0,0:05:41.66,0:05:44.45,Default,,0000,0000,0000,,Your local computer keeps\Na cache of all of the MAC
Dialogue: 0,0:05:44.45,0:05:46.34,Default,,0000,0000,0000,,addresses that it currently knows.
Dialogue: 0,0:05:46.34,0:05:48.72,Default,,0000,0000,0000,,If you wanted to look at \Nthe ARP address table on
Dialogue: 0,0:05:48.72,0:05:52.85,Default,,0000,0000,0000,,your local machine, you \Ncan use the command arp-a.
Dialogue: 0,0:05:52.85,0:05:55.80,Default,,0000,0000,0000,,Let's run the arp-a\Ncommand on my machine.
Dialogue: 0,0:05:55.80,0:06:00.93,Default,,0000,0000,0000,,You can see that I have a number\Nof local devices on the 10.1.10 network.
Dialogue: 0,0:06:00.93,0:06:02.64,Default,,0000,0000,0000,,You can see them all listed here.
Dialogue: 0,0:06:02.64,0:06:06.12,Default,,0000,0000,0000,,There's also some other\Ndevices on my local network,
Dialogue: 0,0:06:06.12,0:06:10.88,Default,,0000,0000,0000,,including some APIPA addresses\Nand some multicast addresses.
Dialogue: 0,0:06:10.88,0:06:13.61,Default,,0000,0000,0000,,Let's say that I want to\Ncommunicate to a switch
Dialogue: 0,0:06:13.61,0:06:15.41,Default,,0000,0000,0000,,that I have on my network.
Dialogue: 0,0:06:15.41,0:06:19.46,Default,,0000,0000,0000,,That switch's IP\Naddress is 10.1.10.210,
Dialogue: 0,0:06:19.46,0:06:21.44,Default,,0000,0000,0000,,and you can see in\Nmy ARP address table,
Dialogue: 0,0:06:21.44,0:06:24.45,Default,,0000,0000,0000,,I don't currently have\Nthat address in the list.
Dialogue: 0,0:06:24.45,0:06:29.42,Default,,0000,0000,0000,,So I'm going to perform a ping,\Nand I'm gonna ping 10.1.10.210,
Dialogue: 0,0:06:29.42,0:06:32.99,Default,,0000,0000,0000,,and I'll get some responses back\Nfrom that particular device.
Dialogue: 0,0:06:32.99,0:06:37.02,Default,,0000,0000,0000,,If I now look at my ARP\Naddress table with an arp-a,
Dialogue: 0,0:06:37.02,0:06:41.99,Default,,0000,0000,0000,,you will see that I have a\Nnew entry for 10.1.10.210,
Dialogue: 0,0:06:41.99,0:06:46.67,Default,,0000,0000,0000,,and you'll see that I have a MAC\Naddress associated with that IP address.
Dialogue: 0,0:06:46.67,0:06:49.64,Default,,0000,0000,0000,,When I performed that ping,\Nthe first thing that occurred
Dialogue: 0,0:06:49.64,0:06:51.89,Default,,0000,0000,0000,,was an ARP request\Nmade to the network
Dialogue: 0,0:06:51.89,0:06:54.08,Default,,0000,0000,0000,,to try to find that\Nparticular device,
Dialogue: 0,0:06:54.08,0:06:56.33,Default,,0000,0000,0000,,and I received an\NARP response, which
Dialogue: 0,0:06:56.33,0:07:00.05,Default,,0000,0000,0000,,then allowed me to send traffic\Nto that device directly.
Dialogue: 0,0:07:00.05,0:07:03.17,Default,,0000,0000,0000,,I captured the ARP\Ncommunication using Wireshark,
Dialogue: 0,0:07:03.17,0:07:06.68,Default,,0000,0000,0000,,which is a packet analyzer, and\Nyou can download and install
Dialogue: 0,0:07:06.68,0:07:09.92,Default,,0000,0000,0000,,Wireshark on your own\Nmachine to see not only ARPs,
Dialogue: 0,0:07:09.92,0:07:12.77,Default,,0000,0000,0000,,but all of the network\Ntraffic on your system.
Dialogue: 0,0:07:12.77,0:07:15.65,Default,,0000,0000,0000,,The first frame that I'm\Nsending is from my device,
Dialogue: 0,0:07:15.65,0:07:18.17,Default,,0000,0000,0000,,and it's sending it\Nout as a broadcast,
Dialogue: 0,0:07:18.17,0:07:22.28,Default,,0000,0000,0000,,and the ARP itself is\Nrequesting the MAC address
Dialogue: 0,0:07:22.28,0:07:25.88,Default,,0000,0000,0000,,for who has 10.1.10.210.
Dialogue: 0,0:07:25.88,0:07:28.01,Default,,0000,0000,0000,,You can see the\Ndetails of the ARP
Dialogue: 0,0:07:28.01,0:07:30.80,Default,,0000,0000,0000,,that are located further\Ndown in the detail.
Dialogue: 0,0:07:30.80,0:07:32.70,Default,,0000,0000,0000,,You can see the\Nsender MAC address,
Dialogue: 0,0:07:32.70,0:07:34.16,Default,,0000,0000,0000,,which is my Apple computer.
Dialogue: 0,0:07:34.16,0:07:38.87,Default,,0000,0000,0000,,You can see my local IP\Naddress, which is 10.1.10.249.
Dialogue: 0,0:07:38.87,0:07:41.00,Default,,0000,0000,0000,,You can see the\Ntarget MAC address,
Dialogue: 0,0:07:41.00,0:07:43.70,Default,,0000,0000,0000,,right now we don't know what\Nthe MAC address is of the target,
Dialogue: 0,0:07:43.70,0:07:46.95,Default,,0000,0000,0000,,so it's all zeros, and you can\Nsee that I'm requesting the MAC
Dialogue: 0,0:07:46.95,0:07:52.82,Default,,0000,0000,0000,,address for the device that has\Nthe IP address of 10.1.10.210.
Dialogue: 0,0:07:52.82,0:07:55.73,Default,,0000,0000,0000,,We very quickly get a response\Nfrom this device, which
Dialogue: 0,0:07:55.73,0:07:58.64,Default,,0000,0000,0000,,happens to be a Cisco\Nswitch, and the response
Dialogue: 0,0:07:58.64,0:08:01.91,Default,,0000,0000,0000,,from the MAC address is\Nfrom the Cisco MAC address
Dialogue: 0,0:08:01.91,0:08:06.26,Default,,0000,0000,0000,,with the sender's IP address,\Nwhich is 10.1.10.210,
Dialogue: 0,0:08:06.26,0:08:08.39,Default,,0000,0000,0000,,and the target is the response back
Dialogue: 0,0:08:08.39,0:08:11.75,Default,,0000,0000,0000,,to my Apple computer\Nand my local IP address.
Dialogue: 0,0:08:11.75,0:08:15.57,Default,,0000,0000,0000,,You can see in the response\Nthat it filled in the sender MAC address,
Dialogue: 0,0:08:15.57,0:08:19.40,Default,,0000,0000,0000,,so instead of being all zeros,\NI see this long MAC address
Dialogue: 0,0:08:19.40,0:08:21.44,Default,,0000,0000,0000,,associated with this IP.
Dialogue: 0,0:08:21.44,0:08:23.90,Default,,0000,0000,0000,,And if you remember\Nthe IP address and MAC
Dialogue: 0,0:08:23.90,0:08:26.24,Default,,0000,0000,0000,,address in my\Nlocal ARP cache, it
Dialogue: 0,0:08:26.24,0:08:31.78,Default,,0000,0000,0000,,matches both of those that were\Nreceived by this ARP response.
Dialogue: 0,0:08:31.78,0:08:34.57,Default,,0000,0000,0000,,That ARP process is what\Nwe use an IP version
Dialogue: 0,0:08:34.57,0:08:37.27,Default,,0000,0000,0000,,4 to be able to\Nidentify a MAC address,
Dialogue: 0,0:08:37.27,0:08:40.36,Default,,0000,0000,0000,,but we don't have\Nbroadcasts in IPv6.
Dialogue: 0,0:08:40.36,0:08:43.63,Default,,0000,0000,0000,,There's also a different\Nprocess for IPv6
Dialogue: 0,0:08:43.63,0:08:47.77,Default,,0000,0000,0000,,to identify the MAC addresses of\Ndevices on your local network.
Dialogue: 0,0:08:47.77,0:08:51.61,Default,,0000,0000,0000,,In IPv6, we use in NDP,\Nwhich is Neighbor Discovery
Dialogue: 0,0:08:51.61,0:08:57.28,Default,,0000,0000,0000,,Protocol, using multicast,\Nspecifically with ICMPv6.
Dialogue: 0,0:08:57.28,0:09:00.46,Default,,0000,0000,0000,,This replaces the ARP function\Nthat we would commonly
Dialogue: 0,0:09:00.46,0:09:04.39,Default,,0000,0000,0000,,see in IPv4 with\Nthis Neighbor MAC Discovery.
Dialogue: 0,0:09:04.39,0:09:06.55,Default,,0000,0000,0000,,This can also be\Nused in conjunction
Dialogue: 0,0:09:06.55,0:09:10.90,Default,,0000,0000,0000,,with SLAAC, which is Stateless\NAddress Autoconfiguration,
Dialogue: 0,0:09:10.90,0:09:14.20,Default,,0000,0000,0000,,which allows the system to\Nautomatically configure itself
Dialogue: 0,0:09:14.20,0:09:18.25,Default,,0000,0000,0000,,with an IP address without\Nusing a DHCP server.
Dialogue: 0,0:09:18.25,0:09:20.08,Default,,0000,0000,0000,,Neighbor Discovery Protocol is also
Dialogue: 0,0:09:20.08,0:09:24.61,Default,,0000,0000,0000,,used to identify any\Nduplicate addresses using DAD,
Dialogue: 0,0:09:24.61,0:09:26.98,Default,,0000,0000,0000,,or Duplicate Address Detection.
Dialogue: 0,0:09:26.98,0:09:29.17,Default,,0000,0000,0000,,If you wanted to see\Nthe conversation that
Dialogue: 0,0:09:29.17,0:09:32.65,Default,,0000,0000,0000,,takes place in IPv6,\Ninstead of using ARP,
Dialogue: 0,0:09:32.65,0:09:37.93,Default,,0000,0000,0000,,we send a neighbor solicitation,\Nor NS, on a multicast address,
Dialogue: 0,0:09:37.93,0:09:43.57,Default,,0000,0000,0000,,and that is the IPv6 multicast that's \Nused for this neighbor solicitation frame.
Dialogue: 0,0:09:43.57,0:09:46.87,Default,,0000,0000,0000,,The response is sent back from\Nthe other side with a neighbor
Dialogue: 0,0:09:46.87,0:09:49.78,Default,,0000,0000,0000,,advertisement, or NA, and that NA
Dialogue: 0,0:09:49.78,0:09:52.96,Default,,0000,0000,0000,,includes the MAC address\Nof that local device.
Dialogue: 0,0:09:52.96,0:09:56.03,Default,,0000,0000,0000,,Although the protocols and the\Nmethod is slightly different,
Dialogue: 0,0:09:56.03,0:10:01.33,Default,,0000,0000,0000,,you can see that the process is very \Nsimilar to the one that occurs in IPv4.
Dialogue: 0,0:10:01.33,0:10:04.30,Default,,0000,0000,0000,,Not only are we sending\Ndata over ethernet networks,
Dialogue: 0,0:10:04.30,0:10:07.18,Default,,0000,0000,0000,,we can also send power\Nover those networks
Dialogue: 0,0:10:07.18,0:10:11.86,Default,,0000,0000,0000,,at the same time using\NPower over Ethernet, or POE.
Dialogue: 0,0:10:11.86,0:10:15.61,Default,,0000,0000,0000,,This allows us to connect\Ndevices such as access points,
Dialogue: 0,0:10:15.61,0:10:18.52,Default,,0000,0000,0000,,voiceover IP phones,\Nand other devices
Dialogue: 0,0:10:18.52,0:10:21.37,Default,,0000,0000,0000,,by simply plugging in\Nan ethernet connection.
Dialogue: 0,0:10:21.37,0:10:23.92,Default,,0000,0000,0000,,You don't have to then\Nplug in a separate power
Dialogue: 0,0:10:23.92,0:10:25.57,Default,,0000,0000,0000,,connection for that device.
Dialogue: 0,0:10:25.57,0:10:28.12,Default,,0000,0000,0000,,That power is coming\Nfrom either the switch,
Dialogue: 0,0:10:28.12,0:10:31.24,Default,,0000,0000,0000,,or another device that's\Nconnected into the network.
Dialogue: 0,0:10:31.24,0:10:34.51,Default,,0000,0000,0000,,If it's coming from the switch, \Nwe call that an Endspan,
Dialogue: 0,0:10:34.51,0:10:37.91,Default,,0000,0000,0000,,or if it's coming from an injector,\Nlike the one you see here,
Dialogue: 0,0:10:37.91,0:10:41.02,Default,,0000,0000,0000,,which sits in the middle of an\Nexisting ethernet connection,
Dialogue: 0,0:10:41.02,0:10:44.08,Default,,0000,0000,0000,,we refer to that as a Midspan.
Dialogue: 0,0:10:44.08,0:10:47.26,Default,,0000,0000,0000,,If your ethernet network\Nis a 10 or 100 megabit
Dialogue: 0,0:10:47.26,0:10:51.01,Default,,0000,0000,0000,,per second connection, then you\Nhave some extra wires inside
Dialogue: 0,0:10:51.01,0:10:53.11,Default,,0000,0000,0000,,of that cable that you\Ncould use for power.
Dialogue: 0,0:10:53.11,0:10:56.29,Default,,0000,0000,0000,,We refer to that as Mode\NB power over ethernet,
Dialogue: 0,0:10:56.29,0:10:58.99,Default,,0000,0000,0000,,where you're sending\Npower on the spare pairs.
Dialogue: 0,0:10:58.99,0:11:01.03,Default,,0000,0000,0000,,But if you're using\Ngigabit connections,
Dialogue: 0,0:11:01.03,0:11:04.66,Default,,0000,0000,0000,,you're using all of those wires\Nfor your gigabit ethernet data.
Dialogue: 0,0:11:04.66,0:11:06.97,Default,,0000,0000,0000,,And in those cases,\Nwe're using Mode A,
Dialogue: 0,0:11:06.97,0:11:11.11,Default,,0000,0000,0000,,where we're sending power\Nand data over the same wire.
Dialogue: 0,0:11:11.11,0:11:13.40,Default,,0000,0000,0000,,You'll find there are a\Nnumber of different power
Dialogue: 0,0:11:13.40,0:11:15.73,Default,,0000,0000,0000,,over ethernet standards,\Nand these standards
Dialogue: 0,0:11:15.73,0:11:18.46,Default,,0000,0000,0000,,are being added to and\Nchanged all the time.
Dialogue: 0,0:11:18.46,0:11:24.37,Default,,0000,0000,0000,,Two very common standards are\Nthe IEEE 802.3af from 2003.
Dialogue: 0,0:11:24.37,0:11:28.00,Default,,0000,0000,0000,,We refer to that as the\Noriginal POE standard, which
Dialogue: 0,0:11:28.00,0:11:32.32,Default,,0000,0000,0000,,provides 15.4 watts of\Ndirect current power,
Dialogue: 0,0:11:32.32,0:11:35.23,Default,,0000,0000,0000,,with a maximum current\Nof 350 milliamps.
Dialogue: 0,0:11:35.23,0:11:38.29,Default,,0000,0000,0000,,An update to that standard\Nis what we call POE+.
Dialogue: 0,0:11:38.29,0:11:42.64,Default,,0000,0000,0000,,This was updated\Nwith 802.3at in 2009.
Dialogue: 0,0:11:42.64,0:11:48.04,Default,,0000,0000,0000,,This also has been incorporated\Ninto the existing 802.3 ethernet standard.
Dialogue: 0,0:11:48.04,0:11:50.92,Default,,0000,0000,0000,,This provides a bit more\Npower on the ethernet network,
Dialogue: 0,0:11:50.92,0:11:57.10,Default,,0000,0000,0000,,25.5 watts of DC power, with a \Nmaximum current of 600 milliamps.
Dialogue: 0,0:11:57.10,0:11:59.49,Default,,0000,0000,0000,,There are other power\Nover ethernet standards,
Dialogue: 0,0:11:59.49,0:12:01.43,Default,,0000,0000,0000,,and these are being\Nupdated all the time,
Dialogue: 0,0:12:01.43,0:12:04.99,Default,,0000,0000,0000,,so make sure you check with the\Nethernet standards from IEEE
Dialogue: 0,0:12:04.99,0:12:09.57,Default,,0000,0000,0000,,to know exactly what options\Nmay be available for you.