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Hi, my name is Michael Gibbs and I'm the founder and CEO of Go Cloud Architects,
and we're an organization that's dedicated towards building high performance cloud computing
and networking careers. Personally, I've been working in technology for over 25 years and I've
been mentoring others to get their first tech job or get promoted in tech for more than two decades,
and my favorite thing in the world is when one of my students calls me and says,
"I just got cloud hired today."
We're going to talk about cloud network training. I consider this AWS networking tutorial to be very
foundational cloud network training, but also very important, and these are critical skills
for the cloud architect or the cloud engineer. So, today we're going to talk about virtual LANs
or VLANs, and a lot of times people will say, "Mike, you're teaching VLANs, but this is cloud
computing." And, VLANs are critical knowledge for the cloud architect for the following reasons.
Most of what we do as cloud architects are we take the systems in the network and the data center,
and we move them to the cloud, which is just another network and a data center that's just
been virtualized. And because of that, we can't move systems that we don't understand. So, the
knowledge of the network is really critical, but when you connect to the AWS cloud, for example,
over a direct connection, you have to send them a VLAN via a trunk or an 802.1Q tag. So,
we're going to talk a lot about what that is. So, the key is even if it's network and
data center technology, you can't get away with cloud computing without knowing about it. So,
this is very important, foundational cloud network training. So, now let's define, what is a VLAN?
A VLAN or a virtual LAN is realistically speaking something we would call a broadcast domain.
What is a broadcast domain? A broadcast domain is an environment where all your users can see each
other's broadcast. So computers themselves, they send out a lot of broadcasts. For example, when a
computer boots up, they send a broadcast message to get an IP address. It's an example. When a
computer wants to reach the router or reach something else, it sends something called an ark,
which is a broadcast, and we can talk about these other cool network things in another video.
But the point is, is broadcasts are sent by systems to identify other systems and things,
and a broadcast domain is when all the users can see each other. So, if you've got one switch by
default, every user can see each other in that same switch. That is called a broadcast domain.
Now, why would an organization use a virtual LAN and why am I talking about broadcast domains?
Here is the reason. Let's look in this graphic that you have here. Let's say I've got
two sets of users or two broadcast domains, and I don't want the users to talk to each other.
I have two options. Option one, two physical switches. Plug my accounting users in one and
my finance users in another switch. I don't make any cabling connections between the switches and I
have logical isolation, segregation, security. My accounting users can't talk to my finance users.
And, guess what, if I've got two switches, this is perfect, but what if I don't want to use two
switches? What if I only need to use five users in one VLAN for example? Do I want to waste the
rest of the ports in the switch? Of course not. So, virtualization came to the switches and a
VLAN or virtual LAN just enables us to chop a physical switch into multiple logical switches.
So, server virtualization enables to take a server and chop it into logical servers,
virtualization and switching, or VLAN enables us to take a switch and virtualize them into
multiple switches and VLANs have been around for at least 30 years. This is not new technology.
So, let's talk about it. If we've got two sets of users, we have the option to have two switches
or take one switch and create two VLANs. Now, how is this all going to work?
Let's say you've got a switch. The switch has 48 parts. You put port zero to 23
in one VLAN and 24 to 47 in another VLAN. And, guess what? Now,
you've got two separate grouping supports that are logically separated from each other. So,
that's how it works. So, now let's look in this picture here. In this picture,
I've got four users. I've got two users that I want to talk to each other, and two users
that I want to talk to each other, but I don't want the other groups talking to each other.
So in this environment, I've created a VLAN 4 and in VLAN 4, I've got me, Mike in there and I see,
oh, Chris in there and we can talk to each other and we can share our secret information.
Now, in VLAN 3, I've got my friend Jesse and my friend Pravin,
and they can talk to each other, but note, Mike and Chris's data and Jesse's in Pravin's
data is logically separated from each other. So we're in the same switch, but we're in two VLANs
and we're in two subnets and we will not be able to talk to each other unless we get off
of the switch, through a router, and get routed to each other. So, we've got good protection,
really good protection, all in the same switch. But, what if we had
multiple switches along the way? That's okay, we can extend our VLANs to multiple switches.
So, switching and virtualization really enables us to get greater utilization of our switches
and much more flexibility and convenience. What's that sound like to you? Just like the cloud,
all these things that you see in the cloud all came from the networking world.
Virtualization of the LAN was one of the first virtualizations and it's again, 30 years old.
So, let's say we want to have two switches. Well, if we ran a cable from... If we had 50
users in one switch, 50 users in another switch, and we ran a cable between them, they could talk
to each other. Well, guess what? If we had two accounting switches and two financing switches
that were logically separate, we could run a cable between them and they'd be isolated,
or what if we had two switches. Two switches that both had two VLANs. Now, if you look in
this graphic, we have just that. We have a VLAN 30 and a VLAN 40. Note, you'll see two switches.
VLAN 30 is available on both switches and VLAN 40 is available on both switches. How
are we connecting VLANs 30 and VLANs 40 in this particular graphic? We have a cable from VLAN
30 to VLAN 30 and a cable from VLAN 40 to VLAN 40. Now, this works perfectly. This is basically
multi-switch communication by putting a cable between both sets of VLANs.
This will work perfectly. This is what you would do if you didn't have something called
VLAN tagging. Now, in this perfect environment where we've got two switches and you can see
two VLANs on each switch, we've got two sets of cables. And, you know what? That
might give us the fastest performance because it's directly a cable, but what if we only had
one fiber optic connection between two buildings? Well, we only have one wire.
What would we do? How could we use one wire to protect and logically isolate our stuff between
two switches? Well, that's where we get involved in 802.1Q tagging. So, here's what happens.
In this environment, as you can see on this graphic,
we've got our layer two frame, which has got a destination address,
meaning a MAC address, a source address being a MAC address and this concept of a tag.
So, what we can actually do is we can take a VLAN and we can add its information via a tag,
and what we can do is we can then create something called the trunk port, which I'll show you in
a minute, and we can have one wire and have our VLAN traffic on that same wire, but separated from
each other because of this 802.1Q tag. So, this 802.1Q tag is magic at security and isolation.
And, now we'll walk you through it, but I just wanted to know how we're going to do this with
this 802.1Q tag. So, let's go back to this graphic here. If you look in this graphic,
here's what you see. Two switches, VLANs 30 and VLANs 40 are both on these two switches,
and we have a single cable between these two switches. That single cable is something called a
trunk. Why is it called a trunk? Because we enable it to allow multiple VLANs on a single wire. Now,
look at that wire very carefully. Note, the blue frame that you see that has 40 on it,
that's coming from VLAN 40 and there's a pink one that says 30,
and there's another blue one that says 40, and there's another pink one that says 30.
We've got a single wire and the traffic is being sent from the switches with the VLAN identifiers.
That's how the traffic is kept separately. Now, how does this magic work? You've got switch one.
When switch one is going to take the traffic and put it on the trunk port, it adds the tags. So,
it's there for the wire. With switch two when it receives the tagged information,
it says, okay, I got to tag. VLAN tag 30, let me remove the tag and send to VLAN 30. I got
a tag going to VLAN 40, let me remove the tag and send to VLAN 40. So, we've got perfectly,
perfectly separated information. To let you know, some service providers call this a
VPN. This is a layer two VPN because we have virtual private communications across
a single wire. So, while it's not what you would typically hear of as a VPN,
many service providers have offerings like this and they are considered to be layer two VPNs.
So, now you know what's going on with the multi-switch VLAN trunking. So, why are
we talking about trunking? Let's recap it again. Trunking is used to connect a switch to a switch.
VLANs are used to logically isolate and virtualize a switch, so you can create enhanced security
by separating different groups of people on the same switch. Now in between switches,
you could run cables between broadcast domains or virtual LANs, or you could use a trunk port,
which is a single cable or a group of single cables that are bundled together where your
traffic is logically isolated and separated by using an 802.1Q tag. So, there you have it. Now,
you know what is a virtual LAN, you know what a trunk is, and you know what an 802.1Q tag is.
This is Michael Gibbs. I'm the founder and CEO of Go Cloud Careers. I hope you've enjoyed this
cloud network video. This is foundational cloud computing training, foundational network training,
and it is absolutely critical skills for the cloud architecture of the cloud engineer. I look forward
to seeing you in another video coming very soon. It was so nice having you join us for this video
today. Let me tell you about some free services we do for the cloud community. Twice per week,
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I look forward to seeing you and I look forward to assisting you in your technology career.
Thank you so much. This is Michael Gibbs from Go Cloud Architects.