How Switching Works | Network Fundamentals Part 11

How Switching Works | Network Fundamentals Part 11
Welcome to the start of switching! Communication is not new, not even electronic communication. In the old days, to make a telephone call, a switchboard operator needed to patch though your call. This means that they had to manually create a path for your phone call to take.
Switching is a lot like this. Switching dynamically creates paths for network traffic to flow through. But it doesn’t do this all on its own. Ethernet, a protocol that operates at layer 2, is critical to how this works.
Each device that uses ethernet has a MAC address. Frames are sent from one MAC address to another. Clever devices like bridges and hubs learn these addresses, and can make better decisions about how traffic is handled because of this knowledge.
It wasn’t always this way though. In the early days we had bus and ring networks, and eventually hubs. These did not have any intelligence, and operated solely at layer 1. They were also only half-duplex, and had to handle collisions.
In this video, we walk through the past, and see how it affects the switching networks that we have today.
Finally we’ll go through a lab to see it all in action.
Lab: networkdirection.net/labsandq...
Quiz: networkdirection.net/labsandq...
The CCENT/CCNA study guide (affiliate): click.linksynergy.com/link?id...
In the next video, we’re taking it further with VLANs
Overview of this video:
0:00 Introduction
2:22 Ethernet
7:31 Adding Hubs
11:16 Improving with Bridges
16:58 Introducing Switches
21:02 Lab Time
Vintage footage from:
• 1939 Film: New Zealand...
• Video
• Episode 11: Computers ...
LET'S CONNECT
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#NetworkDirection

[@NetworkDirection]

Thanks for watching! Lab: networkdirection.net/labsandquizzes/labs/lab-introduction-to-switching/ Quiz: networkdirection.net/labsandquizzes/quizzes/introduction-to-switching-quiz/

[@zackey_tnt]

Just found this channel. Very informative content. Please don't ever quit, you rock!

[@martinmwendakubai2124]

Clear

[@howitzerimpact5166]

It does not work for me. It shows me a bad request error.

[@paulshaddick2312]

I am teaching Communications Technology to 17 year olds. I have few resources available to me and very little background. This Network Fundamentals series is a fantastic resource which our school could not afford to access otherwise. I have happily paid for your quiz answers too!

[@NetworkDirection]

So good to hear this! I'm really glad that these videos are making a difference in young people's lives!

[@alexw6582]

The work and effort you pour into this series is amazing! I am actually studying more into the fields of chemistry/process technology but now binge-watched the series up to now during the last two days! It is amazing to learn something completely new and you explain it so well! Love your graphics/animation to support your words.

[@NetworkDirection]

This is really good to hear! Thanks Alex!

[@techie1818]

You are a lifesaver! Thank you so much for your time spent on educating all of us, starting from the basics! 🤗

[@NetworkDirection]

You are so welcome!

[@DuaLeaD]

Far better teaching than the long, drawn-out TCP/IP, networking, and data comm courses I took in school in the mid 2000s. Man I wish more pro videos were around back then, would have saved me time and money!! Excellent channel, I will be watching all your videos!

[@NetworkDirection]

Thank you! I also wish this type of thing were around back then. That was part of my inspiration to make these.

[@gamingreinvented2173]

Thank you so much for making this free series!❤️

[@NetworkDirection]

You're so welcome!

[@blackettcharlie]

I'd just like to say thanks for this Series! I've made it up to this part in just under a week and I've been really enjoying it. You've given me that spark again that makes me want to get out of bed and learn! I've been missing that for a long time. I'm even enjoying pausing the video to absorb and take notes! Keep it up! You'll probably have another Patron some time soon. :)

[@NetworkDirection]

It's really good to hear that you like it, and have a passion for learning. I'm trying to put some brief study notes in the descriptions too, if that helps at all

[@sachinbkhandare]

You have great knowledge with presentation skills. Very good examples. Easy to understand.

[@ForyantoJayaWigunaChannel]

Your explanation is so clear, I love it...

[@NetworkDirection]

Thanks 👍

[@ali_HA24]

Nicely and clearly explained. A well refresher on switches. Greatly appreciate your efforts!!!

[@NetworkDirection]

Thanks Ali!

[@senmuwizard]

This is top class presentation. The best I have attended so far. Came here to understand only about IP. The presentation was so good that I ended up watching all. :) Thanks for the videos.

[@NetworkDirection]

Really good to hear that, thanks

[@avinashgore5617]

You are awesome I'm getting all concept with ez... Thanks for your efforts...

[@NetworkDirection]

You're welcome. Glad to help

[@Kaya-Atabey]

Greate work on all Videos mate. Especially VXLAN series you made my day on those. Only thing that bugs me in this video is telephone circuit and switch example. Although you are right switching is switching, it would be better to state the circuit switching and packet switching difference since swapping from circuit to packet switching was something really really big.

[@rendog311rendog2]

great video sir! thank you very mutch for your effort!

[@NetworkDirection]

thank you very much!

[@anticringe7887]

this is treasure, thank you very much

[@NetworkDirection]

You're very welcome, thanks for watching!

[@trendyniro]

Your teaching is smooth sir! Thank you

[@NetworkDirection]

So nice of you

[@m3hdim3hdi]

great video thank you so much

[@NetworkDirection]

You're welcome

[@harjos78]

Great Tutorials...

[@NetworkDirection]

Thank you

[@andreytamelo1183]

Thanks!

[@jonathanamakoh5475]

Nice clear explanations, thank you so much! I do have a query on the answers to one of the questions. In Q14, did you mean to pair port Gi0/1with the MAC address 0e00.4d67.cba1, or did you mean for it to be port Gi1/1? From how I understand it, on the answer you gave on Patreon, would have been asking of the latter port.

[@nguyenvanlong2000]

nice series !

[@NetworkDirection]

Glad you enjoy it!

[@Saul-StPaul]

You can also use a pipe | i ( put the last 4 of the Mac )

[@NetworkDirection]

nice tip, thanks!

[@franciscosencion]

Great video!, Question: do you script your videos or just talk on the fly while recording?

[@NetworkDirection]

I do a lot of scripting work, but there's usually some adlibbing, especially around the labs

[@rafaeldonegatti1513]

Holly Cow!!! That's Renata Sorrah at 06:23 starring our brazilian meme Nazaré confusa!!!

[@NetworkDirection]

It's fun throwing a meme in every so often 😀

[@ir4640]

Hi, what animation software are you using for making these awesome videos

[@farokrachid]

Thanks

[@DuaLeaD]

QUESTION for Network Direction: WHY do schools and IT professionals still teach hubs, bridges, and token ring? This is just bizarre to me. I started networking classes back in 2004 and gigabit Ethernet was already becoming popular. When was the last time any hubs or token rings were actually DEPLOYED? 30+ YEARS AGO?! I get that concepts build on each other but if you get into a networking environment that uses these, it is negligence on the company's part. Never in my life have I encountered a real "hub", but then again, I am only 35 years old. Even in 2004, I thought the community college networking courses I was paying good money for were quite antiquated and behind the times. It's like teaching TGV and Mag-Lev train operators how to run steam locomotives.....Am I missing something here?

[@ryanpuckett]

Your videos are amazing! Thank you for all the hard work of producing these. Quick question... When I start the lab in CML2 (Personal) and bring up the console on the switches, the ge1/1 interfaces on each switch (used to connect the two), does not show in the listed interfaces using the "show interfaces status" command line. These interfaces ARE listed in the "Interfaces" tab for each node in the CML Workbench. They just are not appearing when interfaces status is requested on the console when the Switches are booted. Therefore, the servers cannot communicate, and I'm unable to generate any activity between nodes. Any ideas?

[@NetworkDirection]

I'm not sure why that's happening. Does gi0/1 show instead?

[@ryanpuckett]

@@NetworkDirection This is what I get with "show interfaces status": Port Name Status Vlan Duplex Speed Type Gi0/0 OOB management connected routed a-full auto RJ45 Gi0/1 to server-1 connected 2 a-full auto RJ45 Gi0/2 to server-2 connected 2 a-full auto RJ45 Gi0/3 connected 1 a-full auto RJ45

[@NetworkDirection]

@@ryanpuckett yeah, looks like it's using gi0/x instead of gi1/x

[@ryanpuckett]

@@NetworkDirection I just presumed I would be seeing the same report as shown in the video which includes a connection to Switch-2

[@rindu2909]

Hi, Thank you as i do understand all your video. May i know the next video after part 11?

[@NetworkDirection]

Were getting into vlans next. I’m still working on them, so it will be a while before they’re ready

[@squelchedotter]

This was probably cut to make time, but it's still worth noting that while you should not do so, it's very much possible to change a MAC address and that they should not be used for security.

[@NetworkDirection]

Yeah, we can change the MAC in the operating system, which can be used for network attacks, which is what I think you mean by security. The MAC (or BIA) on the network is fixed though. At this level of learning, I think most people need to think of MAC addresses as fixed though. most of the time, we don't assign MAC addresses like we do with IP addresses. Nice thinking, thanks for your comments!

[@daniel723]

Hello! Very nice explenation, however, one thing is not clear to me. How does a computer connected to the LAN which is sending some data know the MAC addres of the destination device?

[@NetworkDirection]

There is a process, discussed in a later video, called ARP (Address Resolution Protocol)

[@carloscordero1362]

Hey, there is a way that i can use this lab on packet tracer?, sorry im new here but im trying my best to learn from you (such a good videos)

[@NetworkDirection]

You can, but it's a bit tricky You have to create the topology in packet tracer (put the switches in place, cable them up) and then copy the config from the lab file to the switches Does that make sense?

[@interpreter5844]

❤❤

[@KenSherman]

Moral of the story: Switch to a switch.

[@NetworkDirection]

😂

[@VipinEdassery]

In 14:59 why the device in right side network is sending the frame to all devices as a response ?

[@NetworkDirection]

Hi Vipin, thanks for your question. On a shared medium like a hub, frames always go to all devices. Switches are different. They will try to prevent flooding by sending the frame out of the correct port only. In this animation the switch send the frame out of one port only. If there are several devices connected to a shared medium (like a hub) which is connected to this port, they will all get the frame. This is why switches are better then hubs! Hope that helps. Have a great day!

[@VipinEdassery]

@@NetworkDirection oh yeah, missed it. Thanks.

[@thedr.6667]

Hello I'm having trouble downloading the files keep getting error, any suggestions?

[@rendirestman4615]

What will happen if when the table is empty, and the destination and the source are in the same segment, is the bridge still broadcasting to other segments to find out which segment the destination is ? I am sorry for my grammar if there's something that make u don't understand my question properly

[@NetworkDirection]

If the MAC table is empty, and the source and destination are on the same VLAN (let's say VLAN 10), here is what will happen: 1. The source will send the frame to the switch 2. The switch will see that the table is empty 3. The switch will then flood the frame out all ports on VLAN 10 So, if there are ports that are on other VLANs, then the frame will not be flooded out those ports Does that help?

[@rendirestman4615]

@@NetworkDirection i asked about bridge, or is it same with how switch works?

[@NetworkDirection]

@@rendirestman4615 A switch is a type of bridge In the old days you could go out and buy a bridge, but it doesn't really work like that now. A 'bridge' is just any device that connects two or more layer-2 segments, and learns MAC addresses

[@rolandasgrigaitis708]

If vendor assigned addresses can only be around ~16 million names, what happens when they release a 17th million Iphone to a customer for example?

[@NetworkDirection]

Good question. They can get another block of MAC addresses assigned to them. A vendor can have more than one assigned for their use

[@aboabdelsamadelraki3717]

How the source host know or learn about the destination mac address to be send ??????

[@NetworkDirection]

We will continue with that in some of the following videos, but basically the source host will use a protocol called ARP. This is a broadcast message which says 'who owns IP x.x.x.x?' The owner will respond with their IP and MAC

[@frenchonionsoup8789]

using the telephone analogy a hub is like a party line?

[@NetworkDirection]

Yeah, it's a bit like that. There's no intelligence in a hub. It just replicates the electrical signals it 'sees' to all other ports

[@omni_reaper2940]

what do you mean by "a MAC address can be learned only on one interface"?

[@NetworkDirection]

Good question. In the MAC address table, there can only be one entry for a MAC address, and one interface assigned to that entry. That's so the switch knows which port to forward a frame out of. If a switch were to see this MAC in the source address field of a frame on a different interface, it will assume that this device has been disconnected from it's pervious interface, and has moved to a new location (like a laptop moving from a desk to a meeting room). So, it will change the entry for this MAC in the MAC address table to show the new interface. But it will only ever have one interface per MAC

[@omni_reaper2940]

@@NetworkDirectionohh ok I get it, thanks dude for the videos they really help out a lot

[@squelchedotter]

I don't think you used the word "daisy chained" correctly here? Doesn't daisy chaining usually refer to a topology where each system is connected to the next? That sounds pretty different from connecting to a common bus.

[@NetworkDirection]

When I was talking about daisy chaining, I was talking about the old physical toplogies that used coax cable (or an alternative) to cable one computer to the next to the next. These were daisy chained, and were part of a bus. A bus topology isn't inherently daisy chained. I tried to show this with the hub diagram, where not all ports are used. Perhaps I didn't make it clear enough.

[@squelchedotter]

@@NetworkDirection Ah, I see, thank you! I've never seen a coax network before so I don't know how networks with those looked.

[@NetworkDirection]

I built one in my home when I was in my late teens. It was out of date even then, but I learned a few things from it. I don't think you could even get the parts to do it now.

[@leblanc666666]

what does the ge1/1 mean again?

[@NetworkDirection]

That's the name of the interface ge = gigabit ethernet first 1 = module number second 1 = port number

[@yerffejmurffy]

Did you mean to say Bit or Byte at 5:05?

[@NetworkDirection]

Nice spotting! I said bytes, and wrote bits. The correct one is bytes. The preamble is 7 bytes, and the SFD is one byte

[@rashmiyadav3618]

Great work, easy to understand but video quality is not good. Please upload HD

[@themortgagechic_ca]

Be grateful. This is free