Network Switch Explained: ASIC chips, Extending your LAN

[Music] [Music] hello and my name is lowell vanderpool and this channel is dedicated to it professionals i.t students and anyone who's interested in technical subjects understanding the enterprise network is a critical skill for the i t professional it's a complex subject for both it students and less experienced i.t technicians because there's just so many technologies inside today's network enterprise switch it just there's no way you can cover it in one so we're going to look at a multi-part video series covering the most important technologies inside a today's network switch we're going to look at vlans because that is so important i was listening to a podcast today explaining some of the huge vulnerabilities in the tcp stack in billions of iot devices and if you're not segmenting your iot devices off your production network it's not going to be pretty one of these days so vlans are so important and we'll look at vlans also i want to share how you can use port mirroring and wireshark to troubleshoot some really tough server applications another real important technology in the enterprise switch is qos quality of service that's going to be important for our voice over ip we don't want all of our corporate users talking to clients sounding like robots now there may be a few co-workers that i would kind of enjoy that but and we've got to make sure that applications like pubg is not running on our network we do have to get work done we also are going to learn mac filtering and spanning tree protocol there's a lot of vulnerabilities at layer 2 and we'll look at how to plug some of them we'll also look at configuring switches at the command line but let's begin with a big picture introduction to the world of the network switch all right so let's talk about one of the basic definitions of a switch is the ability to read mac addresses in an ethernet frame at osi layer 2. this is the basic function of every switch now you see my frame here in the graphic i've got seven octets that are designated for preamble we'll get into that part later then we got six octets that are reserved or this is 48 bits that are designated for a destination mac address then we have six octets or 48 bits reserved for a source mac address those two fields in an ethernet frame are critical to a switch now something really interesting about local area network switches is they really don't care about ip addresses they are only interested in mac addresses here i am in my network settings and i've selected an adapter and i've right mouse clicked and went into properties and i've chosen network connection details and you can see i've i've highlighted in red the physical address of this particular network card that's known as a mac address every network card has a unique 48-bit network id its 24 bits are designated for manufacturing code 24 bits for a serial number you can see on this old melanox network card here they used to put tags on them on the back of this printed circuit board and enable actually let you see the mac address you don't see that very often anymore so generally you have to actually go into settings to see the mac address windows puts that mac address in the ethernet frame without that mac address your ethernet switches are not going to function on your network every network card and your local area network uses a unique number to identify it and this is called a mac address your operating system puts this mac address into the layer 2 ethernet frame this is called the source mac address but if i want to talk to somebody else on the network my operating system has to determine via protocols like arp what mac address of the host you intend to communicate with that mac address is stuck into the destination mac address field i would often take network students into a classroom and i would ask them this question i would say what is your local area network and i would always get that quiet blank stare as they would fidget because they weren't sure what answer i was looking for and then i would pursue and i would say if i went into your company took out every switch in your facility would you have a local area network and no they wouldn't they would have a lot of cables on the floor they would have computers that wouldn't work and they would have a lot of mess but they wouldn't have a local area network because your switch is what makes your local area network work let me add more to the definition of a switch a switch is an electronic device with asic logic chips that logically connect hosts pcs printers servers ib phones into a star topology asic logic chips are very important they are application specific integrated chips every switch has an asic chip in it when i say that switches are asic chips i'm not kidding when you look at a very high-end enterprise switch the cpu is laughable get out the specifications it's like you got to be kidding me i wouldn't run my calculator on the cpu they have tiny memories and limited operating systems and yet those enterprise switches can have a switching capacity of 5 to 12 terabytes how can that be asic chips those chips make up the switching fabric of the device so how did we get the term switch applied to this network box that sits in our idf and our mdfs well that actually comes from our telcom colleagues back in the days when telephone lines and telephone systems were high-tech all these telephone lines would come into the central office there would be thousands of them and there would be a piece of equipment called a telecom switch that would listen to all these lines pick up a subscriber who picked up the receiver got a dial tone they would listen to the audio pulses created by the touch pad and they would then connect it to an outgoing phone line and that piece of equipment was called a switch it was incredibly complex in its architecture well as ethernet matured they stole a lot of the architectural concepts from telecom switches and applied them to ethernet switches so we call our boxes switches now your typical telecom switch is probably around two or three million dollars thankfully our ethernet switches aren't that much now there's lots of chips that can do computational power there's traditional cpus they're great but they don't have a lot of computational power they're flexible but not good for switches there's field programmable gate arrays these require a lot of engineering skills and talent and time but good performance but really high cost then we have asics asics do cost a lot to design once you burn them you can't change them but if you sell enough of them the costs go down most switches use asic now the next generation of switches are on the horizon and some of them are using what's called the protocol independent switch architecture they're actually using photonics intel has their programmable switch chip that runs at 6.4 terabits per second here in the picture you can see the cooling system just to keep that chip at its operational temperature here you can see the architecture of this new switch system that doesn't mean everybody is going down this road but it is one of the next generation now there's a new class of technology for switch chips and they are going to take field programmable gate arrays integrate that with some asic technology into one silicone platform and they're getting about seven terabits per second with this hybrid technology another often overlooked feature of the enterprise switch is the ability to extend the distance between hosts so your cat 5 cat 6 cat 7 cable have a maximum 100 meter limits if you've got a large office space 100 meters as far as you can go with any one cable with switches strategically placed in your office structure you can extend the distance between office workers way beyond 100 meters a favorite topology for ethernet is called the extended star topology so a typical hospital school or business can easily cover 5 to 10 acres of land with the use of some fiber optics and strategically placed switches you can cover a 5 to 10 acre campus and still have everyone on the network now i've purchased a hp 2530 it's a 24 port enterprise switch it has four sfp modules for fiber optic transceivers if you need it i purchased this used and they're very affordable and it allows the it professional id student to really get up to speed with the complexities and configurations of today's switches now i've removed the cover on my switch and you can see my main board i've got my power supply and by the size of the power supply you can tell it's not a poe switch if this was a poe switch about half of the inside of this switch would be power supply it also has a small board for display now this particular board has an arm chip for its cpu it's about 800 megahertz uses about 128 megabytes of flash memory or nvram and basically that's where it stores the operating system and the config files it does have ddr3 256 megabytes of ram it does have two chips on the main board you can see they have tags on them and version information one of those is a linux bootloader the second one is probably a embedded linux kernel this does run the aruba os on this switch now the chips that you see here with the heatsinks on those those are our asic chips those are eight port asics and they handle all 24 ports on the front end of the switch here's my mama cpu this is the broadcom a6 that really handles the back end switching fabric of this particular switch the sfp modules inside the switch are wrapped in metal and that is for rfi and emi protection notice they have holes throughout that metal shielding and that allows airflow those transceivers if you put four transceivers in there they get pretty hot in there now that here in the front of the switch you see two additional rfi emi shielding boxes that take care of the 24 ports that we plug our users into on the front of the switch those do a very very important job they provide voltage suppression noise reduction rfi emi protection on those front-end circuits isolation from transients unwanted electrical noise voltages from damaging the rest of the switch if they were not there your switch would probably last a year if that long if you've been recently hired and you're in an organization as help desk you'll quickly find out that they don't allow you in the server room and they don't allow you in a network closet so how in the world you start learning about switches and networking well one way is to find out what brand and model switches your company uses download the manuals and start learning all the front panel rear panel and leds for all the switches in your company one it shows initiative to your supervisors two when you do get in a network closet and you see a user's port that's bright orange you'll know right away this is a partition port you got a problem with a manual and your switch you can learn a lot by just learning the front panel how to change modes what kind of information can you get from your switch leds there's a huge amount of diagnostic and just good troubleshooting that you can learn from learning the front panel of your switch i purchased this switch from amazon and it was about eighty dollars there's at least 20 good layer two technologies built into this switch that i can learn and really get a grasp on now most switches will have a console port with an rj45 or a micro usb connector with a console port console ports are serial that's not a normal way we connect to devices but in networking that's a very common way we connect to network devices there are some things we have to learn about serial in order to use these jacks now if you're going to use an rj45 for the the large console port you're going to need to purchase a cable like this with a usb type a on one end and an rj45 on the other now when you plug it into your laptop microsoft update will automatically download a driver once you have that rg 45 plugged in it recognizes you're plugged into a serial port and automatically generate a com port in your device manager most of you will have lots of spare micro usb cables so a lot of times that's the easiest way to go again the same thing plug it into the switch plug it into your laptop generally windows update will automatically download the necessary driver for that that particular port and it will generate a com port for you here's my device manager on my laptop when i plugged in the cables you can see it downloaded a driver and that downloaded driver configured a com4 so i want to use com4 when i set up my command line client a command line client is software we're going to download and install on our pc that's going to allow us to go across the network or use a serial port to connect and access a operating system at the command level you can download putty putty is a ssh and telnet client and much more it allows you to run this client software use a lot of configuration options to connect to a network device server and other kinds of devices and access the operating system at the command prompt so because i'm using putty to connect to a serial i'm going to start down here where it says serial right here and i'm going to choose com 4 and i'm going to use a baud rate of 19200 and i'm gonna use eight bits one stop bit no parity and i'm gonna leave flow control as it is now i'm gonna go ahead and go to session and here's where i'm going to choose serial because i'm going to connect to a serial and i'm gonna go ahead and save this configuration so i'm going to put 2530 and i'm going to go ahead and save that configuration so i can always reload that i don't have to put this in every time now your particular switch manual will tell you what serial settings you need to set up for your putty configuration i'm going to go ahead and load my switch configurations into putty and just go down and check them again look at serial make sure all my settings are correct and come up to sessions and now i'm ready to log on to the switch but let's go take a look at my device manager where you can see it downloaded the driver and it installed the virtual com port so let's open up on port and there's your first virtual com port right there you didn't even know you had one of those i hit ok now i hit ok on putty and you can see it displays the information about the switch and it prompts me for my username i type in my username and password and i'm in the command line of the switch operating system we are really looking forward to the year 2021 at youtube to do this channel takes a tremendous amount of time and effort my son nathan is coming on board to give me a hand you can now follow us at twitter at underscore tech savvy team or search us on facebook tech savvy productions if you like what you see subscribe we really love your comments and feedback below on the screen are my new email from tech savvy productions as well as nathan's email address at tech savvy productions feel free to reach out and contact us and hopefully with covid getting behind us we hope that you have a great year in 2021 now check us out part two network enterprise switch [Music] foreign

Channel: TechsavvyProductions

Views: 4,840

Keywords: Networking, Switches, MAC address, LAN, Putty

Id: 0-CIS-u-X_U

Length: 17min 5sec (1025 seconds)

Published: Sat Jan 02 2021