WEBVTT 1 00:00:00.080 --> 00:00:01.050 In this lesson, 2 00:00:01.050 --> 00:00:03.930 we are going to talk about wired connectivity issues. 3 00:00:03.930 --> 00:00:06.480 This includes things like physical connection issues, 4 00:00:06.480 --> 00:00:07.620 cable length issues, 5 00:00:07.620 --> 00:00:10.650 interference issues and port flapping issues. 6 00:00:10.650 --> 00:00:13.530 Now, first, let's talk about physical connections. 7 00:00:13.530 --> 00:00:16.080 Remember, when you're using a wired network connection, 8 00:00:16.080 --> 00:00:18.210 there are lots of different physical components, 9 00:00:18.210 --> 00:00:21.000 and all of these could be the source of your issues. 10 00:00:21.000 --> 00:00:22.920 Now, when you're considering a physical connection 11 00:00:22.920 --> 00:00:25.110 as a source of your connectivity issues, 12 00:00:25.110 --> 00:00:25.943 this might be 13 00:00:25.943 --> 00:00:28.080 because you have some kind of a break in the connection 14 00:00:28.080 --> 00:00:29.790 anywhere along the line. 15 00:00:29.790 --> 00:00:32.130 So as you start considering your different options 16 00:00:32.130 --> 00:00:33.750 of where things can be going wrong, 17 00:00:33.750 --> 00:00:35.130 you need to think about every piece 18 00:00:35.130 --> 00:00:36.780 in that physical connection. 19 00:00:36.780 --> 00:00:38.010 This starts with your client 20 00:00:38.010 --> 00:00:39.960 and it's network interface card. 21 00:00:39.960 --> 00:00:42.060 This NIC or network interface card 22 00:00:42.060 --> 00:00:42.990 is where the network cable 23 00:00:42.990 --> 00:00:44.580 is going to connect into your computer 24 00:00:44.580 --> 00:00:46.830 and transform things from an electrical signal 25 00:00:46.830 --> 00:00:48.630 into a binary one or zero 26 00:00:48.630 --> 00:00:51.180 that can be read and understood by the computer. 27 00:00:51.180 --> 00:00:52.320 Now, moving from our client 28 00:00:52.320 --> 00:00:54.360 and going into our network interface card, 29 00:00:54.360 --> 00:00:55.470 we then come out of that 30 00:00:55.470 --> 00:00:59.417 using that RJ45 connector and it's associated network cable. 31 00:00:59.417 --> 00:01:02.190 This will then connect into a network jack. 32 00:01:02.190 --> 00:01:04.500 Normally in most office environments, 33 00:01:04.500 --> 00:01:05.790 this will be a wall jack 34 00:01:05.790 --> 00:01:08.700 that's going to be using an RJ45 connection. 35 00:01:08.700 --> 00:01:10.650 Once you connect into that wall jack, 36 00:01:10.650 --> 00:01:11.880 on the other side of that, 37 00:01:11.880 --> 00:01:13.770 you have a mini punch down block 38 00:01:13.770 --> 00:01:15.570 on the back of that wall jack, 39 00:01:15.570 --> 00:01:18.360 and this is going to be cabled all the way in through the walls 40 00:01:18.360 --> 00:01:21.480 and over to your patch panel in your network closet. 41 00:01:21.480 --> 00:01:22.950 Once you get to the patch panel, 42 00:01:22.950 --> 00:01:24.930 you're going to connect another patch cable 43 00:01:24.930 --> 00:01:26.340 going from that patch panel 44 00:01:26.340 --> 00:01:29.010 to the particular network device you're connecting to. 45 00:01:29.010 --> 00:01:29.850 Most of the time, 46 00:01:29.850 --> 00:01:33.270 this is going to be a 24 or 48 port switch. 47 00:01:33.270 --> 00:01:34.590 Using that network switch, 48 00:01:34.590 --> 00:01:36.540 your network is going to be able to move traffic 49 00:01:36.540 --> 00:01:38.820 to and from your client and out to the internet 50 00:01:38.820 --> 00:01:42.120 going through a router, a firewall or other gateway. 51 00:01:42.120 --> 00:01:45.090 So if you're having an issue with an unstable connection, 52 00:01:45.090 --> 00:01:48.300 an intermittent connection or no connectivity at all, 53 00:01:48.300 --> 00:01:49.650 it could be that the issue 54 00:01:49.650 --> 00:01:51.960 is with the physical layer of that network 55 00:01:51.960 --> 00:01:55.110 as I just described all these different pieces and parts. 56 00:01:55.110 --> 00:01:57.000 To test this connection from end to end, 57 00:01:57.000 --> 00:01:58.950 you can connect a network cable tester 58 00:01:58.950 --> 00:02:01.230 to the wall jack of your particular port 59 00:02:01.230 --> 00:02:03.720 and then to the patch panel on the other side. 60 00:02:03.720 --> 00:02:05.760 This will test all the interior wiring 61 00:02:05.760 --> 00:02:07.080 going from that wall jack 62 00:02:07.080 --> 00:02:09.570 through the walls and into that patch panel. 63 00:02:09.570 --> 00:02:10.890 If this works properly, 64 00:02:10.890 --> 00:02:13.500 then it's a matter of testing the individual cables, 65 00:02:13.500 --> 00:02:15.390 connecting the wall jack to your client 66 00:02:15.390 --> 00:02:17.550 or the patch panel to your switch. 67 00:02:17.550 --> 00:02:19.230 And if you find a cable that is faulty, 68 00:02:19.230 --> 00:02:21.720 the easiest thing to do is replace that cable. 69 00:02:21.720 --> 00:02:23.580 If you find that the wall jack is faulty 70 00:02:23.580 --> 00:02:25.710 or the connection to the patch panel is faulty, 71 00:02:25.710 --> 00:02:26.670 in those cases, 72 00:02:26.670 --> 00:02:29.130 you'd want to take the cable off of those connectors, 73 00:02:29.130 --> 00:02:30.180 restrip the cable, 74 00:02:30.180 --> 00:02:33.420 and then repunch them down using a proper punch down tool 75 00:02:33.420 --> 00:02:36.000 and then testing that connection from end to end again. 76 00:02:36.000 --> 00:02:36.833 Another quick way 77 00:02:36.833 --> 00:02:39.120 to determine if your network connection is working properly 78 00:02:39.120 --> 00:02:40.380 at the physical layer 79 00:02:40.380 --> 00:02:41.213 is to simply look 80 00:02:41.213 --> 00:02:43.171 at the back of your network interface card. 81 00:02:43.171 --> 00:02:45.330 On the back of your network interface card, 82 00:02:45.330 --> 00:02:48.090 you'll usually have two or three lights on it. 83 00:02:48.090 --> 00:02:48.923 These three lights 84 00:02:48.923 --> 00:02:50.940 are used to indicate the status of the connection, 85 00:02:50.940 --> 00:02:52.380 the activity on that connection 86 00:02:52.380 --> 00:02:54.184 and the speed of that connection. 87 00:02:54.184 --> 00:02:55.920 If you're dealing with the link light, 88 00:02:55.920 --> 00:02:57.630 this will show that you have a valid link 89 00:02:57.630 --> 00:02:59.430 all the way back to the switch. 90 00:02:59.430 --> 00:03:01.470 If you look at the back of your network interface card 91 00:03:01.470 --> 00:03:04.200 and you don't see the link light is actually lit up, 92 00:03:04.200 --> 00:03:06.090 this means you have a physical issue 93 00:03:06.090 --> 00:03:07.560 somewhere along that path 94 00:03:07.560 --> 00:03:08.610 and you need to troubleshoot that 95 00:03:08.610 --> 00:03:11.581 to identify which cable or punch down is incorrect. 96 00:03:11.581 --> 00:03:14.940 Second, you're going to have what's called the activity light. 97 00:03:14.940 --> 00:03:16.140 The activity light will blink 98 00:03:16.140 --> 00:03:18.150 anytime data is being sent or received 99 00:03:18.150 --> 00:03:20.040 through that network interface card. 100 00:03:20.040 --> 00:03:21.030 This is a way to see 101 00:03:21.030 --> 00:03:24.330 if the network is actively sending or receiving information. 102 00:03:24.330 --> 00:03:25.440 That's a great thing to look at 103 00:03:25.440 --> 00:03:27.690 to verify that you have not just a good link, 104 00:03:27.690 --> 00:03:30.090 but you're actually sending data back and forth. 105 00:03:30.090 --> 00:03:31.230 The third light that you'll find 106 00:03:31.230 --> 00:03:32.600 on the back of a network interface card 107 00:03:32.600 --> 00:03:34.800 only exists on some cards, 108 00:03:34.800 --> 00:03:35.910 but this is going to display 109 00:03:35.910 --> 00:03:38.160 what speed that card is operating at. 110 00:03:38.160 --> 00:03:41.580 This could be 10, 100 or 1000 megabits per second 111 00:03:41.580 --> 00:03:43.680 depending on your network interface card. 112 00:03:43.680 --> 00:03:45.240 Normally, this light will be off 113 00:03:45.240 --> 00:03:46.804 if you're using 10 megabits per second, 114 00:03:46.804 --> 00:03:50.010 it'll be orange if you're using 100 megabits per second, 115 00:03:50.010 --> 00:03:51.120 and it'll be green 116 00:03:51.120 --> 00:03:53.610 if you're using the 1000 megabits per second connection 117 00:03:53.610 --> 00:03:55.620 on your network interface card. 118 00:03:55.620 --> 00:03:57.810 The second connectivity issue you might come across 119 00:03:57.810 --> 00:03:59.850 when you're dealing with wired network connectivity 120 00:03:59.850 --> 00:04:01.980 is an issue with your cable length. 121 00:04:01.980 --> 00:04:02.813 If you remember, 122 00:04:02.813 --> 00:04:05.730 we talked about the fact that unshielded twisted pair cables 123 00:04:05.730 --> 00:04:08.130 can only go a maximum of about 100 meters 124 00:04:08.130 --> 00:04:10.620 before you have issues with connectivity. 125 00:04:10.620 --> 00:04:12.090 So you always want to look 126 00:04:12.090 --> 00:04:13.685 at the entire length of the connection 127 00:04:13.685 --> 00:04:16.530 and verify how long it actually is. 128 00:04:16.530 --> 00:04:19.680 Remember, if we're going from the client to the wall jack, 129 00:04:19.680 --> 00:04:21.360 the wall jack to the patch panel 130 00:04:21.360 --> 00:04:22.920 and the patch panel to the switch, 131 00:04:22.920 --> 00:04:24.870 the entire distance along that line 132 00:04:24.870 --> 00:04:27.060 cannot be more than 100 meters. 133 00:04:27.060 --> 00:04:29.760 If it is, you're going to have to use some sort of a repeater 134 00:04:29.760 --> 00:04:31.230 to be able to increase the signal, 135 00:04:31.230 --> 00:04:33.510 or you're going to have connectivity issues. 136 00:04:33.510 --> 00:04:34.343 Now, personally, 137 00:04:34.343 --> 00:04:36.030 I like to keep all of my network connections 138 00:04:36.030 --> 00:04:38.400 under 90 meters instead of 100 meters 139 00:04:38.400 --> 00:04:40.530 because this gives me a little bit of extra padding 140 00:04:40.530 --> 00:04:41.910 in that space requirement 141 00:04:41.910 --> 00:04:43.701 and make sure I don't have any connectivity issues 142 00:04:43.701 --> 00:04:44.534 like I would 143 00:04:44.534 --> 00:04:47.005 if I'm going right up against that 100 meter mark. 144 00:04:47.005 --> 00:04:48.810 Now, the third issue we need to talk about 145 00:04:48.810 --> 00:04:52.080 when it comes to wired network connectivity is interference. 146 00:04:52.080 --> 00:04:52.913 That's right, 147 00:04:52.913 --> 00:04:55.500 interference does affect our wired connections. 148 00:04:55.500 --> 00:04:58.020 When I talk about interference with wired connections, 149 00:04:58.020 --> 00:04:59.340 really this is going to be coming 150 00:04:59.340 --> 00:05:01.530 from an external interference source. 151 00:05:01.530 --> 00:05:03.930 Generally, this will include things like power lines, 152 00:05:03.930 --> 00:05:06.450 fluorescent lighting, motors or generators 153 00:05:06.450 --> 00:05:08.460 that are located near your cables. 154 00:05:08.460 --> 00:05:10.115 For example, I've seen a lot of businesses 155 00:05:10.115 --> 00:05:12.780 that will run their network connections through the ceiling. 156 00:05:12.780 --> 00:05:13.800 And when they do that, 157 00:05:13.800 --> 00:05:14.730 they'll actually have the cables 158 00:05:14.730 --> 00:05:17.310 going directly over one of their fluorescent lights. 159 00:05:17.310 --> 00:05:19.560 Well, anytime those fluorescent lights are on, 160 00:05:19.560 --> 00:05:21.277 it's actually generating extra power 161 00:05:21.277 --> 00:05:23.430 that's being fed into those wires, 162 00:05:23.430 --> 00:05:24.360 and this power 163 00:05:24.360 --> 00:05:27.210 can actually have a source of external interference for us, 164 00:05:27.210 --> 00:05:29.400 and this will actually jumble the ones and zeros 165 00:05:29.400 --> 00:05:31.590 that are being sent across that line. 166 00:05:31.590 --> 00:05:33.090 If you're finding that you have this issue 167 00:05:33.090 --> 00:05:34.410 with external interference, 168 00:05:34.410 --> 00:05:35.760 what you want to do is verify 169 00:05:35.760 --> 00:05:38.400 that your cables are not going across any power lines 170 00:05:38.400 --> 00:05:40.560 or fluorescent lighting in the ceiling. 171 00:05:40.560 --> 00:05:43.170 Additionally, if you have to operate your network cables 172 00:05:43.170 --> 00:05:45.120 near or around power lines, 173 00:05:45.120 --> 00:05:47.400 fluorescent lighting, motors or generators, 174 00:05:47.400 --> 00:05:49.500 you should use a fiber optic connection 175 00:05:49.500 --> 00:05:52.110 instead of an unshielded twisted pair copper connection 176 00:05:52.110 --> 00:05:53.670 because fiber optic cables 177 00:05:53.670 --> 00:05:56.490 transmit their data using light instead of electricity, 178 00:05:56.490 --> 00:05:59.280 and therefore they're immune to that external interference 179 00:05:59.280 --> 00:06:00.900 caused by things like power lines, 180 00:06:00.900 --> 00:06:03.570 fluorescent lighting, motors and generators. 181 00:06:03.570 --> 00:06:06.300 The final wired connectivity issue you need to be aware of 182 00:06:06.300 --> 00:06:08.820 is what's referred to as port flapping. 183 00:06:08.820 --> 00:06:10.260 Now, port flapping is caused 184 00:06:10.260 --> 00:06:12.630 when you have an intermittent connectivity issue 185 00:06:12.630 --> 00:06:15.300 between your client and your network switch. 186 00:06:15.300 --> 00:06:16.620 When you have port flapping, 187 00:06:16.620 --> 00:06:19.230 this can occur either on the client's network interface card 188 00:06:19.230 --> 00:06:21.360 or the switch's interface. 189 00:06:21.360 --> 00:06:22.650 Now, with port flapping, 190 00:06:22.650 --> 00:06:24.510 the status of that network interface 191 00:06:24.510 --> 00:06:26.640 is going to be going up and down continually 192 00:06:26.640 --> 00:06:29.370 from an upstate to a downstate and back. 193 00:06:29.370 --> 00:06:30.990 And this is why it's called port flapping, 194 00:06:30.990 --> 00:06:33.720 because we are flapping from an up or on state 195 00:06:33.720 --> 00:06:35.700 to a down or off state. 196 00:06:35.700 --> 00:06:37.200 Most often, port flapping 197 00:06:37.200 --> 00:06:39.210 is going to be caused by either bad cabling, 198 00:06:39.210 --> 00:06:40.380 external interference 199 00:06:40.380 --> 00:06:43.650 or a faulty network interface card on your client. 200 00:06:43.650 --> 00:06:44.880 In any of these cases, 201 00:06:44.880 --> 00:06:47.160 you need to check your switch configuration interface 202 00:06:47.160 --> 00:06:48.060 and its logs 203 00:06:48.060 --> 00:06:49.080 to be able to see how long 204 00:06:49.080 --> 00:06:51.030 the port is remaining open in an upstate 205 00:06:51.030 --> 00:06:53.670 versus how often it's going into a downstate. 206 00:06:53.670 --> 00:06:54.540 This will help you understand 207 00:06:54.540 --> 00:06:56.430 exactly how bad your problem is, 208 00:06:56.430 --> 00:06:58.020 and then you can go to work 209 00:06:58.020 --> 00:07:00.510 figuring out exactly where this issue is coming from, 210 00:07:00.510 --> 00:07:02.940 whether that's bad cabling somewhere along the line 211 00:07:02.940 --> 00:07:04.740 or some kind of external interference 212 00:07:04.740 --> 00:07:06.780 that's affecting your network cabling. 213 00:07:06.780 --> 00:07:10.260 So remember, when it comes to wired connectivity issues, 214 00:07:10.260 --> 00:07:11.970 you can have four main types. 215 00:07:11.970 --> 00:07:13.860 These are physical connection issues, 216 00:07:13.860 --> 00:07:14.970 cable length issues, 217 00:07:14.970 --> 00:07:17.673 interference issues or port flapping issues.