In this article, we’re getting to have a glance at cabling, and Wi-Fi the Ethernet protocol and network addressing hang around you’ll like it when it involves connecting devices there are two options wired, and wireless wired connections are around since the start of your time is the “> that’s the late 1960s as far as networks are concerned a wired network uses cables to attach devices together wireless technology in a general has existed for an extended time consider radios and mobile phones her example the wireless technology that we consider most with networking is named Wi-Fi which has been around since the early 1990s cables are often copper or fiber copper cables are usually cheaper and are quite common for brief distances data is shipped over copper cables using electrical signals this suggests that they are an often suffering from outside interference I’ll explain why this happens a touch later fiber cables are made from strands of glass data is shipped through the fiber within the sort of light fiber is more expensive but is basically good over longer distances also he is not suffering from outside inference a good land uses a protocol called Ethernet remembers that a protocol may be a set of rules that devices within the network agree on Ethernet is formed up of tons of various parts a number of these parts describe sorts of cabling, and therefore, the speeds as they run out other parts describe how the info should be formatted and sent this is often called media access control the rationale Ethernet is layered like this is so devices with different cables and different speeds can all still communicate imagine a workstation that features a one gigabit connection to the network it wants to send data to a server that features a 10 gigabit connection the workstation prepares a message it formats it consistent with the media access control rules than it prepares to send the message consistent with the physical rules that it’s to follow when the server receives the messages it decodes it at the physical layer the message that is left is the same because it was at the station smack layer as you’ll see even though they need different connections the hosts can still communicate because of this layering system Ethernet was designed by a gaggle called I Tripoli has created many various standards for various technologies all of their standards have a code number standards that start with eight zero two is used for lands Ethernet for instance may be an arrow two three remember how Ethernet is a group of standards each of those is assigned one or two letters for instance tanki Ethernet is 802.3 an n if you want to see a full list of Ethernet standards have a glance at the Wikipedia page on I Triple E arrow 2.3 coats like arrow 2.3 a and may be tricky to recollect so each of those physical standards have friendly names which are a touch easier to understand for instance at O 2.3 an n is also referred to as 10 G base T this provides us a touch of a touch about what the quality is the ten G refers to the speed of the connection during this case, it’s 10 gigabits per second base is brief for base band this suggests that it uses a digital signal the choice is broadband which uses an analogue signal the T means are often “> this is often a UTP cable I’ll explain what a UTP cable is soon you’d possibly see other cables here like LX which refers to a kind of fiber optic cable electrical cables use electrical signals these are a pattern of ones and zeros the receiver must decode this pattern the pattern is named an encoding scheme to send electrical signals a circuit is required this suggests the electrical cables got to contain several wires the foremost common copper cable is named 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 remember to highschool science for a while does one remember that electricity and magnets are related to electricity flowing through a copper cable creates a magnetic flux a magnetic flux and a copper cable can create electricity the problem is that a pair of wires running parallel create little electromagnetic field the sector from one pair of wires can affect the signal on another pair of wires this is named crosstalk UTP eliminates most crosstalk by twisting the pair of wires together each pair is not running in parallel in order that they don‘t generate the sector if you’ll find an old network cable that you simply don‘t need to cut the top off it and strip back the plastic round the outside you’ll likely find four pairs of wires counting on how all the cable is there can also be a plastic core or a piece of string they’re color-coded so each pair features a solid color, and a striped color for instance one pair will have brown and striped brown wires now, I said that you’ll probably have four pairs there wasn‘t always four pairs though older Ethernet standards like 10 base T and 100 base T only needed two pairs, but to realize 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 just cat 6 the category defines things just like the number of pairs within the cable the thickness of the wire and the way 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 then on sometimes there will be an e or an at the top of the name cat5e and cat6 are example of this is where the first standard has been improved upon newer standards support better speeds over longer distances for instance you’ll use a cat 5 cable on a ten 0 Meg network but if you would like to run a gigabit network you need a minimum of cat 5e if you would like 10 gig cats 6 is okay up to around 55 meters but if you run cat 6a you’ll have a 10 gig link that works up to 100 meters each newer standard backwards compatible with the older technology, For example, you’ll use a cat 7 cable on a 100 Meg link your cable features a connector at both ends this is named a 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 got 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 wire on both ends this suggests that pin 1 connects to pin 1 pin 2 connects to pin 2 then on this is called a straight through cable as the wires go straight through from one end to they are some pairs are useful transmitting data et al. are used for receiving for instance, 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 once you connect a number to a switch the switch to something very clever it knows that pair 1 is employed for transmitting and pair 2 for receiving so it does the other 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 an equivalent logic is used on pair 2 the key point here is that a straight through cable is employed to connect a number to a switch but what if you would like to attach a number to something isn‘t a switch perhaps another host or a router the pins not line up correctly they’re both using an equivalent pairs for receive and transmit so instead we’d like to use slightly different cables what we do use may be a crossover cable this swaps the pairs at one end so transmitted lines up with receive once more this is also the sort of cable you would use if you would like to connect one switch to a different switch now you’re probably thinking that’s a pain now I even have to stress about two different sorts of Ethernet cables and ensuring I use the proper one at the proper time to prevent from this dilemma, we’ve a technology called Auto mdi-x a tool of support although mdi-x can detect if the incorrect cable is employed it can Then, logically switch the functions of the pins in order that they match the cable the 100 base and newer standards support auto mdi-x so within the world you do not have to think too hard about the cable you employ actually crossover cables are becoming pretty rare these days if you are going to try to a network exam though you ought to still remember the difference between a straight-through and crossover cable once 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 will 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 is a bit different to everything we’ve discussed so far, but it works and you simply need cat 5e to support it within the interesting requirement in both thousand base standards and newer is that they require Auto mdi-x support the choice 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 opposite end it works just like the example here which shows a laser following a stream of liquid the pulsing light is a special way|in our way|otherwise“> differently to encode information fiber is usually used between networking devices like routers and switches getting to |it should“> it’s going to even be utilized in servers I’ve never seen workstations use fiber but i assume anything’s possible I’m going to take a fast detour and talk about something called duplex devices got to both send and receive data UTP cables can send and receive at an equivalent time if both ends of the link support this it’s called full duplex sometimes a device won’t be ready to send and receive at an equivalent time instead it’ll send for a short time stop then receive for a short time is often “> are often “> are often “> this is often called half duplex these devices can still send and receive, but they will not do both directly full or half duplex is decided by the cabling that’s used the capabilities of the device at both ends of the link and therefore, the software configuration there are two alternative ways that fiber can be used First, you’ll use single core only this operates in half duplex mode because it can’t send and receive at an equivalent time the other option is dual core this is a full duplex together core is devoted to sending, and one is devoted to receiving remember though, there’s easy to urge the cause involved if you connect the fiber, and it doesn‘t work try swapping the cause at during a ll|one amongst|one in every of“> one amongst the ends the enterprise network will mostly use dual core fiber this suggests between switches routers and servers service provider networks like your internet and when providers offer new single core there you’d like to remember, there are two sorts of fiber these are called single mode and multi mode they’ll look an equivalent, but they’re different due to the kinds of sunshine they use multimode which is understood as A MMF uses a LED light this isn‘t a particularly powerful light so it’s used over shorter distances say around 500 meters or fewer which makes it is useful to attach devices within the same building the LED light may be an additionally cheaper to supply making multimode fiber the cheaper option single mode fiber or SMF uses a laser light this makes it costlier but it’s capable of for much longer distances you’ll easily get ─ two kilometers or more counting 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 offer you an or internet access albeit a fiber-optic cable is formed of glass he’s still flexible you’ll bend the cable Well, a minimum of to some extent the fiber cable features 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 doesn‘t necessarily mean that the cable won’t work, but it won’t work well the manufacturer of the cable should be able to inform you what a suitable Bend radius is there are different connectors that the fiber cables may use quite few actually once you remember that fiber is not only for networking the most 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 normal to ascertain these during a dual core configuration, but they can be separated into single core SC connectors are older and bigger they appear to be less common lately they’re more often seen in a wiring closet, some switches will have a special port that appears empty some switches are made up entirely of those ports these are made for installing a transceiver module these can be used for different purposes, but basically they are so you’ll mix and match the highest of cabling you employ 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 also as different cable lengths for instance an extended cable run of 40 kilometers will need a costlier transceiver than you’ll need for a 1 kilometer run the rationale that a number of these switches have many of those ports is so you’ll mix and match which transceivers you employ for the work, you’ll even use a rj45 transceiver for when you would like to use UTP copper cable for that matter you’ll even get a special copper cable with SFPs inbuilt it’s called the dual x cable but that’s another story our method of communication wireless aka Wi-Fi it doesn‘t use cabling in fact, but I should mention it quickly anyway wireless networks use access points these devices are sort of switch for the wireless network whilst devices like your phone or laptop hook up with the access point the access point can also connect to the wired network this is how wired, and wireless devices can be within the same network Wireless is a great way to connect end-user devices you would not 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 Triple E this describes how radio waves are wont to format and encode information and to urge different speeds while they are not an equivalent Ethernet and attitude 11 do share many similarities within the way data is formatted but that’s something we will check out once more.
let’s have another quick summary networks are often wired or wireless wired networks may use copper or fiber cables during a wired LAN the Ethernet standard is wont to describe how data is formatted it also covers cable types link speeds, and the way to encode data on the physical link UTP is the commonest copper cable modern UTP cable has four twisted pairs of wires some are used for sending and others are used for receiving the cable could also be straight through for connecting devices to a switch or could also be cross over for connecting devices for every other modern lands support auto mdi-x which enable the device to detect the cable used and adapt as required a full duplex device can send and receive at an equivalent time a half duplex device can only do one at a time an example of these are often found in fiber cabling dual core fiber is full duplex single core is half duplex if you would like a brief and cheap fiber run you’ll use multimode fiber if it’s to be longer you would like the more expensive single mode you furthermore may got to use the proper transceiver within the device you’re connecting the fiber to if cables aren‘t getting to work for you than you can believe using wireless access points to make a wireless network.
It’s that point again don‘t skip this it’s good to check yourself think about the thousand based a typical what speed does this run up also what sort of cable does this use what sort of UTP cable would you employ to attach a number to a switch what about connecting a switch to another switch when does one get to use auto mdi-x when might you would like to use fiber instead of UTP cable when would you would like to use single mode rather than multi mode what is Bend radius with which sort of cable would you’ve got to be especially careful of the bend radius what’s required to support full duplex.
Let’s return to our Soho Network for a while we use diagrams like this to point out how a network fits together notice that this is often the logical view of the network it doesn‘t show all the physical details just like the number of switches use the sort of cabling then on it’s just a easy way to point out how things fit together imagine that the PC wants to send a print job to the printer is network enabled therefore the computer can send a print job over 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 proper device knows what to try to well this does happen once in a while but if this happened all the time the network would be very inefficient imagine if all the endpoints were sending directly also this might be insecure what if this was private information all the opposite endpoints would see it and what if there are several printers which one would accept the print job or do all of them start printing now the print job must be sent only to the right printer but how does this happens each device on the network features an n address this is an often like your home address your address is exclusive, and it enables others to seek out you contact you and deliver packages during a land each device has two addresses they each have IP address and a MAC address these two addresses are utilized in alternative ways we’re getting to have a quick overview of these addresses here and probe more detail in later videos let’s start with MAC addresses each host has a minimum of one MAC address to be more accurate each network card has a Mac so multiple networks cards means multiple Macs when the network card is manufactured, the Mac is permanently assigned we will not change it this may be a lso referred to as the burned-in address as each network card has its own MAC address each Mac is bound to be unique a MAC address is employed when one device must communicate with another device within the same land segment I’ll explain what I mean by this sooner each device also has IP address this address is chosen by us the network administrators once we choose addresses we will make them easier to recollect we also use IP addresses when one device want to speak with another but IP addresses are special as they permit us to access hosts on a special land segment imagine that our small company has been very successful and has now grown instead of just one Network we’ve decided to make a second Network each of those networks is a land segment these are joined alongside a router this router is a component of both LAN segments so, it’s job is to pass network traffic from one segment a special “> to a different MAC addresses are used within the local LAN segment so once we send a message to mention a printer in another network we will not be just use the MAC address of the printer IP addresses though are different we will use the IP address of the printer when we would like to send it a message check out “> let’s examine how this works the PC 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 pc 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 might raise tons of questions for you but don‘t be concerned we’ll look at how these works in additional detail once more.
For now just remember these things hosts have a MAC address and IP address a MAC address is employed only within a LAN segment IP address can be used within a LAN segment but is additionally used to pass traffic to a different land segment.
now another brain-teaser to urge you thinking computers and devices have MAC addresses who assign this MAC addresses does the PC has only one MAC address or does it have more if you would like to send a message within the local LAN segment does one even need IP address within the next article of this series will investigate network models this will teach us what a network stack is and the way abstraction helps the network.