Cabling Devices | Network Fundamentals Part 2

in this video we're going to have a look at cabling and Wi-Fi the ethernet protocol and network addressing hang around you'll love it when it comes to connecting devices there are two options wired and wireless wired connections have been around since the beginning of time that's the late 1960s as far as networks are concerned a wired network uses cables to connect devices together wireless technology in general has existed for a long time think of radios and mobile phones her example the wireless technology that we think of most with networking is called Wi-Fi which has been around since the early 1990s cables can be copper or fiber copper cables are usually cheaper and are very common for short distances data is sent over copper cables using electrical signals this means that they can be affected by outside interference I'll explain why this happens a bit later fiber cables are made of strands of glass data is sent through the fiber in the form of light fiber is more expensive but is really good over longer distances also he's not affected by outside inference a wide land uses a protocol called Ethernet remember that a protocol is a set of rules that devices in the network agree on Ethernet is made up of a lot of different parts some of these parts describe types of cabling and the speeds as they run out other parts describe how the data should be formatted and sent this is called media access control the reason Ethernet is layered like this is so devices with different cables and different speeds can all still communicate imagine a workstation that has a one gigabit connection to the network it wants to send data to a server that has a 10 gigabit connection the workstation prepares a message it formats it according to the media access control rules then it prepares to send the message according to the physical rules that it has to follow when the server receives the messages it decodes it at the physical layer the message that is left is the same as it was at the station smack layer as you can see even though they have different connections the hosts can still communicate because of this layering system Ethernet was designed by a group called I Tripoli I Tripoli have created many different standards for different technologies all of their standards have a code number standards that start with eight zero two are used for lands Ethernet for example is arrow two three remember how Ethernet is a group of standards each of these is assigned one or two letters for example tanki Ethernet is 802.3 a n if you'd like to see a full list of Ethernet standards have a look at the Wikipedia page on I Triple E arrow 2.3 coats like arrow 2.3 a and can be tricky to remember so each of these physical standards have friendly names which are a bit easier to understand for example at O 2.3 a n is also known as 10 G base T this gives us a bit of a hint about what the standard is the 10 G refers to the speed of the connection in this case it is 10 gigabits per second base is short for baseband this means that it uses a digital signal the alternative is broadband which uses an analogue signal the T means that this is a UTP cable I'll explain what a UTP cable is soon you might see other cables here like LX which refers to a type of fiber optic cable electrical cables use electrical signals these are a pattern of ones and zeros the receiver needs to decode this pattern the pattern is called an encoding scheme to send electrical signals a circuit is needed this means the electrical cables need to contain several wires the most common copper cable is called unshielded twisted pair or UTP modern UTP cables contain four pairs of wires where each pair forms a circuit electrical signals over copper cables can be disrupted by interference think back to high school science for a while do you remember that electricity and magnets are related electricity flowing through a copper cable creates a magnetic field a magnetic field and a copper cable can create electricity the problem is that a pair of wires running parallel create a small electromagnetic field the field from one pair of wires can affect the signal on another pair of wires this is called crosstalk UTP eliminates most crosstalk by twisting the pairs of wires together each pair is no longer running in parallel so they don't generate the field if you can find an old network cable that you don't need cut the end off it and strip back the plastic around the outside you'll probably find four pairs of wires depending on how all the cable is there may also be a plastic core or a piece of string they're color-coded so each pair has a solid color and a striped color for example one pair will have brown and striped brown wires now I said that you will probably have four pairs there wasn't always four pairs though older ethernet standards such as 10 base T and 100 base T only needed two pairs but to achieve one gig and 10 gig speeds all four pairs are needed not only other different Ethernet standards but the cable itself has different standards you will hear of terms like category 6 or simply cat 6 the category defines things like the number of pairs in the cable the thickness of the wire and how tightly they're twisted for example cat 2 has only two pairs cat six has four pairs cat six has thicker wires than cat five and so on sometimes there'll be an e or an a at the end of the name cat5e and cat6 a are examples of this this is where the original standard has been improved upon newer standards support better speeds over longer distances for example you can use a cat 5 cable on a 100 Meg network but if you want to run a gigabit network you need at least cat 5e if you want 10 gig cat 6 is okay up to around 55 meters but if you run cat 6a you can have a 10 gig link that works up to a hundred meters each newer standard is backward compatible with the older technology for example you can use a cat 7 cable on a 100 Meg link your cable has a connector at both ends this is called an rj45 connector this is the part that you connect to your network card or switch port this connector has eight pins these line up with the eight wires inside the cable the wires need to line up with the correct pins that's why the Y's are color-coded there are different color schemes you could use this one here is called 568b a standard UTP cable will match the wires on both ends this means that pin 1 connects to pin 1 pin 2 connects to pin 2 and so on this is called a straight through cable as the wires go straight through from one end to the are some pairs are useful transmitting data and others are used for receiving for example pair 1 transmits while pair 2 receives you'll see here that I've used the terms Rx and TX these simply mean receive and transmit when you connect a host to a switch the switch to something very clever it knows that pair 1 is used for transmitting and pair 2 for receiving so it does the opposite it uses pair 1 to receive and pair 2 to transmit so when the host sends on pair 1 the switch receives on pair 1 the same logic is used on pair 2 the key point here is that a straight through cable is used to connect a host to a switch but what if you want to connect a host to something is not a switch perhaps another host or a router the pins no longer line up correctly they are both using the same pairs for receive and transmit so instead we need to use slightly different cables what we do use is a crossover cable this swaps the pairs at one end so transmitted lines up with receive once again this is also the type of cable you would use if you want to connect one switch to another switch now you're probably thinking that's a pain now I have to worry about two different kinds of Ethernet cables and making sure I use the right one at the right time to save you from this dilemma we have a technology called Auto mdi-x a device of support although mdi-x can detect if the wrong cable is used it can then logically switch the functions of the pins so they match the cable the 100 base and newer standards support auto mdi-x so in the real world you don't have to think too hard about the cable you use in fact crossover cables are getting pretty rare these days if you're going to do a network exam though you should still remember the difference between a straight-through and crossover cable when we get to 1,000 base though things change this uses all four pairs of wires while older standards only required two there are two ways this can work which are called 1,000 base T and 1000 base TX the TX standard uses two pairs for sending and two paths for receiving you will need cat6 cabling or higher if you want to use this standard the T standard uses all four ports for sending and receiving it's a bit different to everything we've discussed so far but it works and you only need cat 5e to support it in the interesting requirement in both thousand base standards and newer is that they require Auto mdi-x support the alternative to copper cabling is fiber cabling fiber cables use strands of glass which are sometimes called a pipe or a core a light pulses down the fiber strand which is received at the other end it works like the example here which shows a laser following a stream of liquid the pulsing light is another way to encode information fiber is often used between networking devices like routers and switches it may also be used in servers I've never seen workstations use fiber but I guess anything's possible I'm going to take a quick detour and talk about something called duplex devices need to both send and receive data UTP cables can send and receive at the same time if both ends of the link support this it's called full duplex sometimes a device will not be able to send and receive at the same time instead it will send for a while stop and then receive for a while this is called half duplex these devices can still send and receive but they can't do both at once full or half duplex is determined by the cabling that's used the capabilities of the device at both ends of the link and the software configuration there are two different ways that fiber can be used first you can use single core only this operates in half duplex mode as it can't send and receive at the same time the other option is dual core this is full duplex as one core is dedicated to sending and one is dedicated to receiving be aware though there's easy to get the cause mixed up if you connect the fiber and it doesn't work try swapping the cause at one of the ends the enterprise network will mostly use dual core fiber this means between switches routers and servers service provider networks like your internet and when providers offer new single core there you need to be aware that there are two types of fiber these are called single mode and multi mode they may look the same but they are different because of the types of light they use multimode which is known as MMF uses a LED light this is not a particularly powerful light so it is used over shorter distances say around 500 meters or less which makes it useful to connect devices in the same building the LED light is also cheaper to produce making multimode fiber the cheaper option single mode fiber or SMF uses a laser light this makes it more expensive but it is capable of much longer distances you can easily get two kilometers or more depending on the hardware you're using you would typically use single mode fiber between different buildings or your service provider may run single mode fiber into your building to give you an or internet access even though a fiber-optic cable is made of glass he's still flexible you can bend the cable well at least to a point the fiber cable has a maximum bender radius the Bend radius is how tightly the cable can be coiled up before attenuation occurs attenuation is where the signal is degraded or lost this does not necessarily mean that the cable won't work but it won't work well the manufacturer of the cable should be able to tell you what an acceptable Bend radius is there are different connectors that the fiber cables may use quite a few in fact when you remember that fiber is not just for networking the main ones we see in data networking are called LC and SC LC other smaller connection types which are usually used on switches and routers it's common to see these in a dual core configuration but they can be separated into single core SC connectors are older and larger they seem to be less common these days they're more often seen in a wiring closet some switches will have a special port that looks empty some switches are made up entirely of these ports these are made for installing a transceiver module these can be used for different purposes but basically they are so you can mix and match the top of cabling you use different transceivers support a different cable type this includes single mode and multimode fiber some transceivers will support both but they also support different speeds like 1g or 10g as well as different cable lengths for example a long cable run of 40 kilometres will need a more expensive transceiver than you will need for a one kilometer run the reason that some of these switches have many of these ports is so you can mix and match which transceivers you use for the job you can even use an rj45 transceiver for when you want to use UTP copper cable for that matter you can even get a special copper cable with SFPs built in it's called the twin x cable but that's another story the our method of communication is wireless aka Wi-Fi it doesn't use cabling of course but I should mention it quickly anyway wireless networks use access points these devices are like a switch for the wireless network whilst devices like your phone or laptop connect to the access point the access point may also connect to the wired network this is how wired and wireless devices can be in the same network Wireless is a good way to connect end-user devices you wouldn't normally see a server or router connected to an access point Wi-Fi does not use the arrow 2.3 Ethernet standard instead Wi-Fi uses the attitude 11 standard which was also created by the I Triple E this describes how radio waves are used to format and encode information and to get different speeds while they're not the same Ethernet and attitude 11 do share many similarities in the way data is formatted but that's something we can look at another time let's have another quick summary networks can be wired or wireless wired networks may use copper or fiber cables in a wired LAN the ethernet standard is used to describe how data is formatted it also covers cable types link speeds and how to encode data on the physical link UTP is the most common copper cable modern UTP cable has four twisted pairs of wires some are used for sending and others are used for receiving the cable may be straight through for connecting devices to a switch or may be cross over for connecting devices to each other modern lands support auto mdi-x which enable the device to detect the cable used and adapt as needed a full duplex device can send and receive at the same time a half duplex device can only do one at a time an example of this can be found in fiber cabling dual core fiber is full duplex single core is half duplex if you want a short and cheap fiber run you can use multimode fiber if it has to be longer you need the more expensive single mode you also need to use the right transceiver in the device you're connecting the fiber to if cables aren't going to work for you then you can consider using wireless access points to create a wireless network it's that time again don't skip this it's good to test yourself think about the thousand based a standard what speed does this run up also what type of cable does this use what type of UTP cable would you use to connect a host to a switch what about connecting a switch to another switch when do you need to use auto mdi-x when might you want to use fiber instead of UTP cable when would you need to use single mode instead of multi mode what is Bend radius with which type of cable would you have to be especially careful of the bend radius what is required to support full duplex you let's go back to our Soho Network for a while we use diagrams like this to show how a network fits together notice that this is the logical view of the network it doesn't show all the physical details like the number of switches use the type of cabling and so on it's just a simple way to show how things fit together imagine that the computer wants to send a print job to the printer the printer is network enabled so the computer can send a print job over the network the network has several endpoints so how does a computer know where to send the data could it just send a message to everything on the network and hope that the right device knows what to do well this does happen on occasion but if this happened all the time the network would be very inefficient imagine if all the endpoints were sending at once also this could be insecure what if this was private information all the other endpoints would see it and what if there are several printers which one would accept the print job or do they all start printing no the print job needs to be sent only to the correct printer but how does this happen each device on the network has an address this is like your home address your address is unique and it enables others to find you contact you and deliver packages in a land each device has two addresses they each have an IP address and a MAC address these two addresses are used in different ways we're going to have a brief overview of these addresses here and dig into more detail in later videos let's start with MAC addresses each host has at least one MAC address to be more accurate each network card has a Mac so multiple network cards means multiple Macs when the network card is manufactured the Mac is permanently assigned we can't change it this is also known as the burned-in address as each network card has its own MAC address each Mac is guaranteed to be unique a MAC address is used when one device needs to communicate with another device in the same land segment I'll explain what I mean by this sooner each device also has an IP address this address is chosen by us the network administrators when we choose addresses we can make them easier to remember we also use IP addresses when one device wants to communicate with another but IP addresses are special as they allow us to access hosts on a different land segment imagine that our small company has been very successful and has now grown rather than just a single Network we have decided to create a second Network each of these networks is a land segment these are joined together with a router this router is part of both LAN segments so it's job is to pass network traffic from one segment to another MAC addresses are used within the local LAN segment so when we send a message to say a printer in another network we can't just use the MAC address of the printer IP addresses though are different we can use the IP address of the printer when we want to send it a message let's see how this works the computer prepares a message for the printer and it adds the printers IP address the printer is on another network so it needs help to deliver the message the computer knows that the router can help so it adds the routers MAC address to the message and sends it the router receives the message and strips its own MAC address off the message in its place it puts the printers MAC address on instead the router then forwards the message to the printer this may raise a lot of questions for you but don't worry we'll look at how this works in more detail another time for now just remember these things hosts have a MAC address and an IP address a MAC address is used only within a LAN segment an IP address can be used within a LAN segment but is also used to pass traffic to a different land segment now another brain teaser to get you thinking computers and devices have MAC addresses who assigns these MAC addresses does the computer have only one MAC address or does it have more if you want to send a message in the local LAN segment do you even need an IP address in the next video of this series will investigate network models this will teach us what a network stack is and how abstraction helps the network if you found this helpful please subscribe and click the notification button also if you liked it please click the like button and tell me what you thought in the comments

Channel: Network Direction

Views: 473,352

Rating: 4.9619827 out of 5

Keywords: cabling devices, connecting devices and addressing network fundamentals part 1, netwok direction, networking fundamentals, networking basics, network fundamentals, half duplex, connecting devices in networking, smf, mmf, single mode, multi mode, copper, laser, sc, lc, single core, dual core, patch panel, full duplex, exam, switch, router, mac, ip, wifi, ethernet, 802.11, networking hardware, ipv4 protocol, free ccna, computer network, intro to networking, ccna, ccent

Id: Ud8UeNgdaz4

Length: 25min 25sec (1525 seconds)

Published: Thu May 03 2018