Hi, everyone, and welcome back.
Now, in today's video, we are going to discuss about the basics of transit gateways.
Now, before we understand more in detail about this topic, let's take an example.
Use case of a VPC based connectivity and look into the challenges that are involved.
Now, generally in organizations, when there are multiple EPCs and you require that all of these VPC
should be able to communicate with each other, then one of the standard approaches that is used is
VPC peering.
However, depending upon the number of VPC, VPC peering also comes with its own set of complexities.
For example, let's say that there are four VPC where there are certain part of applications that are
running, and you have a use case where all of these applications should be able to communicate among
each other.
So let's say we want to establish the communication between all of the VPC.
You establish a VPC peering.
So from the VPC number one, you connect this with the VPC number two in terms of a peering setup.
So now VPC one and VPC two can communicate.
Then you also establish a peering between VPC one and VPC four.
Similarly, you also establish a peering between VPC one and VPC three.
Now, at this stage VPC one will be able to communicate to all other VPC.
However, VPC two will not be able to communicate with VPC number four and VPC number three.
So what you need to do, you have to establish a connectivity between VPC two and VPC three and similarly
connectivity between VPC two and VPC four.
All right.
So at a high level overview, more the number of EPCs, the more the number of peering connections that
you will have to establish.
Now, there are organizations that have hundreds of accounts, and the amount of VPC that they have,
it ranges in hundreds to even thousands.
When you have such large scale VPC, such large scale of accounts, then setting up peering connection
is something that will create issues and it can also hit the overall limits.
So in order to simplify this, A has released a feature of Transit gateway at a high level Overview.
Transit Gateway connects your VPC and ON-PREMISE networks to a central hub.
So same example where you have for VPC.
So instead of establishing peering connection among each other what you do, you deploy a central transit
gateway and you connect all of the VPC to the transit gateway.
And that's about it.
Once these VPC are connected, all of these VPC will be able to communicate among each other.
So now let's consider that you have 200 v PCs.
The overall architecture remains to be the same.
You connect the VPC to Transit Gateway, and that's about it.
And this simplifies a lot of things now as we're discussing in the first pointer, is that the transit
gateway allows you to connect the VPC as well as on premise networks.
So there are multiple type of attachments that you can associate with Transit Gateway.
So let's take a much more larger set up.
So in this kind of a setup, you'll see that you have two pieces that are associated along with that.
You also have a direct connect connection from a corporate data center.
You also have a site to site VPN from another corporate data center.
So this is also one of the architectures that you will generally see in the organizations that have
been using Transit Gateway.
So let's do one thing.
Let's jump into a demo to understand things in more detail.
Now, for today's demo, I already have the transit gateway that is configured.
So from the VPC console, if you'll see, let's go to Transit Gateway and you'll see we have one transit
gateway with a name of demo transit Gateway that is already available.
Now, if you look into the attachments associated with the transit gateway, there are two attachments
here.
You have the VPC attachment number one, and you have the VPC attachment number two.
So very similar to the use case that we were discussing.
Instead of attaching for VPC, we have attached to VPC just for demo to keep things simple.
And now what we'll do.
Since both of these VPC are attached to the transit gateway, we'll look whether the instance from the
VPC number one is able to communicate to the instance to the VPC number two.
So let's do one thing.
Let's quickly go to the easy to console.
In fact, let me also show you both the VPC.
So here you see we have two VPC.
One is the default VPC with the CIDR of one 7231 second is the custom VPC with the side of 192 168.
Now, if you look into the instances, I have two instances running each in individual VPC, so VPC
zero one instance should have a site of one 7231 VPC zero two instance should have a side of 192 168
So let's do one thing.
Let's copy the side of the instance.
Number two and from the instance, number one, we'll go ahead and we'll verify if we are able to perform
ping.
So let's try to do a ping.
On the instance.
Number two, and you see the communication is working perfectly well.
Now, I'll also quickly show you the route table associated with the VPC.
So within the roundtable you'll see that it states that the traffic that is going to another VPC should
go towards the transit gateway.
So you see that target is transit gateway.
So this is how the traffic from the VPC is directed towards the transit gateway.
And from here it is directed and routed to the appropriate VPC or any other resource that is attached
to the transit gateway.
Great.
So that is a very high level overview about what the transit gateway is all about.
And with this will conclude today's video.