Switching Loop, Bad Cables, Port Configuration and VLAN Assignment

Video Activity

Switching Loop, Bad Cables, Port Configuration and VLAN Assignment This lesson covers trouble shooting common wire and switch issues; which include the following: Switching loop: broadcast packets loop forever; might be the result of multiple links in place. Bad cables/Improper cables: physical cable or connector damage, incorrect cable types can a...

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31 hours 29 minutes
Video Description

Switching Loop, Bad Cables, Port Configuration and VLAN Assignment This lesson covers trouble shooting common wire and switch issues; which include the following:

  • Switching loop: broadcast packets loop forever; might be the result of multiple links in place.
  • Bad cables/Improper cables: physical cable or connector damage, incorrect cable types can also cause issues with transmitting and receiving data.
  • Incorrect Port Configurations: Port type could the issue, as could the VLAN settings
  • VLAN Assignment: check VLAN subnet and port configuration
Video Transcription
Hi and welcome to cyber dot i t. My name's Anthony and I'm your local subject matter expert here for Network Plus and today we're gonna be talking about troubleshooting common router and switch issues. Now we have our wired devices. We've talked in an earlier model about our troubleshooting our wireless devices, but let's take a look at some of our
wired routers and switches and what, maybe be causing issues with those.
Well, first we have are switching loop. Now, a switching loop is when we have an endless loop between packets on the layer to level. So this is typically in the form of things such as broadcast storms, where we have our switches configured in such a way that they form loops. And when we send a broadcast packet out,
our switches just probably propagate those
broadcast packets out to all of our loops forever.
So if we have
a switching loop where we have
three switches
and then a router
and our three switches forming a loop, well, if a single client sends out a broadcast packet on one of the switches, those switches are just going to send the packets in circles for in it forever, and that will effectively shut down our network. So we need to be aware of these loops that conform.
Now we may actually have these loops in our network on purpose for redundancy sake.
That way, if one link isn't able to be access for whatever reason, our information can travel through a different path. So in order to help mitigate these loops, we may need to have things set up such a spanning tree protocol protocol we've talked about in an earlier segment about how spanning tree protocol
helps mitigate loops by finding out where loops are forming
and then blocking certain links so that broadcast packets can't propagate over those links to help effectively shutting off the loop. But spanning tree protocol can fail. So if spanning tree poder protocol fails and these loops are forming that we may need to change devices in our network, we may need to swap out a device or temporarily change our topology
by removing certain links and disconnecting cables
until we can get those devices changed. And we can prevent those loops by use of a protocol such a spanning tree protocol. So wanna watch out for those loops on, and we did talk about Spain entry protocol and more in depth in a previous module.
Next, we have bad cables and improper cables. Now, bad cables can refer to physical
actual actually physically damaged cables or connector to our connectors. So if we have a cable that was slightly cut or crimped into, were stepped on and has a short in it, or maybe the connector on the end is broken, then that would be a bad cable. We actually have a physical cable that has some our connector that has physical damage to it,
and we also have incorrect cable types. Well, we will talk about later about our different says between our crossovers versus are straight cables. But simply put, we have cables that have the same connectors on different ends and look exactly the same.
But the way the wires air set up to the different pins on our connectors
indicates how data can transfer over those cables. So it indicates whether this is a cable that we use to connect different devices together, like a client computer to a router, or if this is a cable that we used to connect similar devices like a router to a router. So knowing the differences between these cables helps us to prevent
from connecting devices using incorrect tables like using us cross over cable
instead of a straight cable.
Then we also have incorrect cable types, such as the incorrect cat off cable such as Cat five or CAT six cable. These different cat cables will also talk about when we talk about our actual physical cables. We just no, we just need to know that if we're using incorrect category cable for our devices,
then there may be some issues with actual would actually transmitting and receiving data over those cables.
And then we have maximum distance succeeded. And am I now maximum distance exceeded? If we have a cable that's going too long, we can run into a tin mutation, which is where we have a signal which is being sent over a cable, and that signal over time starts to lose power.
So when it's doing that over time, we reach a maximum cable length. So if we exceed the maximum recommended distance for our cable, then we may actually run into issues with being able to send signals over that cable
and then. Lastly, we have e m. I am. I stands for electromagnetic interference. When we have cables that are transmitting information, they're transmitting them with electrical signals and other electrical signals in the Our proximity can affect those electrical signals on our cable. That's why we don't do things like run cables over
over light sources in the ceiling or run cables,
bundle cables extremely extremely tight together and run them parallel to each other for long distances. We may do those in some cases, but that those leave those cables more susceptible to electromagnetic interference. Where the electorate were. The electromagnetic fields produced by electrical by electrical devices
can distort the electrical waves that we have going through our cables.
So it's important to realize that, and it's important to check for source of sources of electromagnetic interference where we're installing cables.
Next, we have different port configurations on our devices. Now, if we have incorrect port configurations on our devices, we may notice that we are unable to connect our device. We aren't able to connect at all or were not able to connect devices like we want them to connect
so poor configurations can refer to our actual ports themselves the port type
and making for refer to things such as a span or mirrored port or trump port. If we're trying to connect a computer to, Ah, switch that we have a certain port configured as a span port and we try to connect that computer into the span port to connect to the Internet, it's not gonna work.
That span port that mirrored port isn't goingto work to allow connection out to the Internet. It's just going to receive data,
so we need to check. Those poor configurations are trump. Ports aren't going to be are goingto work like our access ports are for RV lands. If we're trying to just connect the computer to a particular to a villain through a switch, will need to configure that as an access port for particular device
rather than a trunk port, where we'll configure multiple switches that host villains
when we configure those switches to communicate with each other,
and then we have our different be land settings, and our Mac lists are villian settings refer to how our computers connect to our switch and what V land they're on, and then we have our Mac exclusions, where we only allow certain computers with certain Mac addresses to connect to our switch to connect to our network.
So we need to check all of our different configurations on our ports on our switches
and make sure that we don't have any special settings applied to a particular port. Or, if we do have a device that we want special settings to be applied to it, such a zit being on a particular villian or it being a trunk port. Then we need to make sure that we check and verify those settings in our on our device before we just assume.
And then we have Port Speed versus and Duplex. When we talk, we're talking about duplex settings were talking about how our port communicates with other ports, Whether it's simplex, half duplex or full duplex. A port set to simplex will only communicate in one direction.
It'll either only send or receive
half duplex means a port could do both a port consent and receive, but it can't do both at the same time. Simplex. That can. On Lee do 1/2 duplex. It could do both, but only one at a time,
and then we have full duplex and full duplex is when our port can send and receive at the same time.
We also have our port speeds. We have our 10 megabits per 2nd 100 megabits per second and 1000 megabits per second. And these port speeds help our ports to know how fast they can send or receive data. Now. Typically, our duplex and our speed settings are goingto ought to negotiate with whatever
device they're connected to you over whatever cable they're sending over.
But sometimes these this auto configuration doesn't work. Or maybe we're connecting to a device that is already manually set and isn't set the auto configure. So we need to make sure that we check the settings for the ports, whether it's auto configured or if it's set to 1/2 duplex, 100 speed or half duplex, 1000 speed or duke
our full duplex, 100 or 1000 speed.
So we need to make sure that we're checking for those configurations, checking those port speeds and duplex settings and making sure that they're compliant with each other. If they're not set to auto negotiate
and then, lastly, here we have our V Lian assignments now are villian. Assignments are going to be when we're trying to connect
access computers to a switch and assign them to particular villains. Or we're trying to connect multiple switches together that host the land's through trunk ports. We need to make sure that we're checking our poor configurations and were properly assigning different ports to different V. Lance.
If we want a certain computer to be on a certain V land, we need to make sure that airport settings on
that village on that switch are correct.
Now, in addition to our access port settings, we also need to change. Make sure our trunk port settings are correct as well. Our trunk port settings allow our switch to send information from multiple V lands over one port, and if that trunk port is set is just a standard access port,
then we may not be able certain V lands on our switch may not be able
to communicate properly,
and then we have that would be like our all of our billions must be on our same sub net are villains. If we have one particular V land, that villian must must be on the same sub net as Thea other devices within its same Dilan due to the fact that villians air going toe
communicate a lot over layer to they're not gonna communicate through any layer three routing
or networking protocols. So all of these device, all of our all of our devices on the same villain must be within the same sub net. That cannot be on a separate network segment that can't be on a different subject.
are different. Be Leon's, however,
do you can be on different sub nets because they need to be able to. They need to route in order to communicate with other V lands. So if we have a green villain and a blue villain than the green V, Lan and the Blue V Land cannot communicate to each other unless they go unless their information and listener data is routed. Now,
even if they're on the same physical switch,
if they're set up in different V lands, unless that switch is capable of routing, unless that switches a multilayer switch and is able to route the data between that villain A in our villian green and Gillian Blue that it's gonna have to send that data through a router in order for this in order for the two villains to communicate.
So we need to make sure that we're checking all of RV land assignment configurations were checking our port configurations in which ports were signing to certain villains were checking that all of our that RV lands. All of the computers within a certain villian are on the same sub net.
We're checking that. We know the difference between our access ports and our trunk ports are access ports connecting our clients
to the villain trunk ports connecting are different switches together. And then that we make sure that if we need to communicate between the lands, we have some way that some path that RV Leon's can use to route the data in between between the multiple V lands
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