Issues with Cable

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Time
8 hours 19 minutes
Difficulty
Beginner
CEU/CPE
8
Video Transcription
00:00
okay, The next issue we're going to need to troubleshoot is our cable.
00:04
Some of the hardware tools that we talked about earlier will help with this, but I wanted to spend the next section going over some of the common problems with cable
00:13
to start out. One of the most common problems is Attenuation.
00:17
Attenuation is all about the fact that the signal deteriorates over distance.
00:22
Some cable types are much more resistant to attenuation than others.
00:26
For instance, the fiber optic and go a couple 1000 m before you have problems with signals quality. So take that and compare it to his twisted pair. You can only get 100 m before attenuation.
00:37
That's a pretty noticeable difference.
00:39
Some mitigating Strategies with Attenuation A lot of our devices many of our devices also amplify signals.
00:46
When talking about switches, they're going to boost the signal, and perhaps other network connectivity devices will do the same. So keep your round short. Know your type of cable?
00:56
Just a quick review from what we talked about earlier.
00:59
For Attenuation, you can usually think of 100 m for twisted pair. Regardless of the category, you can think of a couple 1000 m for multi mode fiber and for Caracciolo cable
01:10
with a thick net, which is our G eight. You can think about 500 m.
01:14
No those distances, and that's going to help you troubleshoot any sort of issues of distance.
01:19
Other problems we might have
01:22
think of voice specifically when I see jitter.
01:23
We also have to think about latency. Latency is a delay, and certainly not just VoIP communications that are subject to delay Cincy.
01:34
If you watch TV, for instance, and there's an anchor person who was talking to one of their correspondents out in the field, the anchor person will ask a question. And then there's that weird, awkward silence where you can tell the reporter on the other end is just waiting and waiting. And then all of a sudden they start talking. But then it's apparent that as soon as they start talking, the message just comes through.
01:53
As awkward as that little period is, what we see is over time they can make their adjustments, and then it's much better with you and see you can usually just and kind kind of sort of work out that problem
02:04
because of the fact that jitter is variable delay, often caused by environmental situations or circumstances. It's much more difficult to predict.
02:13
Crosstalk
02:15
Crosstalk is a problem with copper wires that are running adjacent to each other.
02:19
Basically, you got signals on one cable that caused electromagnetic interference and an adjacent cable,
02:24
and that is why the wires are crossed
02:27
with twisted pair. A pair of wires twist around each other that tends to reduce issues with cross talk.
02:34
Now electromagnetic interference.
02:37
This can really interfere with traffic being sent on the network.
02:40
You can have a lot of data corruption, and this is caused by heavy machinery, Bluetooth devices, cell phone devices.
02:47
There are a lot of devices, all electronic devices amid some form of radiation. So how much is going to dictate the degree of interference?
02:57
Twisted Pair is particularly susceptible to am I? And because of that, there is an unshielded twisted pair, which is the one that's really most sexual.
03:06
But then there's a shielded, twisted pair that provides a little bit more shielding and a little bit better resistance. However, you're still not going to run twisted pair cabling down an elevator shaft, just not what it was designed to do. We want to keep that in mind that even with shielding, there's still a degree of susceptibility.
03:23
Other issues pinata issues,
03:27
regardless of if you're cramping your cables. Remember, we saw those correct configurations back with T 5 68 A and B are twisted pair and RJ 45 jacks.
03:38
Whatever the cable type you're working with, you want to test your cable and make sure you both send and receive and that your pin outs are as they should be.
03:46
Incorrect cable type.
03:47
There are a couple of issues with cable.
03:50
Throughout the years, we certainly evolved a speed. We've gone from Category three cable category five to Category five e and six, and then Cat seven is here,
04:00
even if it hasn't been officially standardized yet. Cut seven is here, so we've gone from 10 megabits per second to 10 gigabits per second.
04:08
What we want to realize is often we may have legacy equipment on our network, or we may be using older cable. So if you are running cat three cable, even if our switch transmits a gigabit speed, the network is going to be forced to run at its lowest component. So it may be that we're just having latency and we're having issues with performance.
04:27
Could be that we're using older cable or an older device that operates at a lower speed.
04:31
We also have to think about using Am I using the right cable for this particular situation?
04:38
You've already talked about how twisted pair is very susceptible to am I?
04:42
Well, you can also have that same problems with Caracciolo Cable because co ax cable is very rigid. It's not very flexible.
04:48
It's not something that you want to run from drop ceilings. So we definitely want to make sure that we're using the best type of cable for our environment.
04:57
Sometimes ports go bad.
04:59
It could be because of the M I. A lot of electronic devices are particularly susceptible to static electricity and SD electrostatic discharge.
05:09
It could be an issue. It could be any one of a million issues. Check your lights. Usually, we're looking for a green light, and that light is yellow for a prolonged period of time or orange. That gives you an indication something's going on
05:21
a lot of times, if you see orange or yellow, that indicates that there are a lot of collisions. That interference may be working, but something's going on in that segment.
05:30
Of course, if you get no lights when you plug in that indicates the port, maybe bad,
05:34
plug into another port or try to think cable on that port. Just kind of play around it. Never underestimate the possibility of cable being bad.
05:43
A connector being coming, disconnected or report on the switch or whatever. Device going bad
05:49
transceiver mismatch
05:51
all sorts of devices uses transceivers there transceivers for radio communication for VoIP or a telephone E. There are transceivers for Ethernet networks, so making sure that we have the right transceiver type for the right environment. That's a must.
06:06
Yeah,
06:08
this just goes back to cables being poorly wired or mis wired. You've got the instances here. We've got the reverse or how the cable should be configured.
06:15
Good cable testers will tell you which end the cable is configured incorrectly.
06:23
If we talk about duplex, we have simplex half duplex and full duplex.
06:28
Simplex is one way communication
06:30
can only send in this direction, period to sending across the wire. There's half duplex or I can send and receive, but not at the same time, I think of a walkie talkie or we can both communicate. But I have to push the button and talk. And while I'm talking, you can talk. That's half duplex.
06:46
Then there's full duplex, which means we can both send and receive simultaneously most devices to die when we talk about switches. Did I their full duplex?
06:57
An earlier reports. In time, our switches were half duplex. Then, as we're moving on to full duplex devices, we had reports that would allow auto negotiation auto negotiation kind of make sure that both devices are using the same duplex.
07:11
If you have one device using a different duplex type, then the communication will fail. It won't work if you manually configure duplex communications. And honestly, the only driving factor for you to do that would be legacy equipment. If you do manually configured for half duplex on one end,
07:28
you have to manually configure the other end as well. If you leave it on auto negotiation. Assuming both devices support auto
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