Hadian And welcome back.
Now into this video, we are going to discuss about the Gateway load balancer at a high level overview.
Now, before we discuss about the Gateway load balancers, it is important that we first understand
the problem statement and the challenges that the organization used to face.
One of the important things specifically for large enterprises is the traffic inspection.
Now, traffic inspection can be related to IEDs, EFPs.
It can be related to firewalls, deep packet inspection related use cases, etc..
And this is the reason why in most of the enterprises you will see some kind of a virtual network appliance
related to IEDs, EFPs, firewalls that have been deployed in abuse.
Now, let's also look into it from the architectural perspective to see on how it integrates.
So let's say that you have a subnet one where all of your application servers are hosted and there is
a requirement of some kind of a traffic inspection.
So what the organizations do, they use some kind of virtual network appliance related to IEDs, EFPs,
etc., which are being provided by various providers like Cisco, ET cetera.
And this network appliance can take care of the overall traffic inspection.
Now, let's assume that there is an Internet gateway which is used to send and receive traffic across
the Internet.
So if an application server wants to send or receive the traffic from the Internet, that traffic first
goes to the network appliance where it is inspected from the network appliance, it goes towards the
Internet gateway.
Similarly, the traffic from the Internet, it goes to the network appliance where the traffic is inspected.
And after the inspection network appliance will send the traffic back to the application server.
So this is one of the use cases that you will commonly see in enterprises.
Now, before we proceed further, let's go ahead and understand, based on this architecture, how the
route tables can be defined.
Now, at the subnet one where the application servers are hosted, let's look into the route table here
you define there will be one default route of the local VPC and the target is local.
However, for any other destination like 0000, which also includes the traffic towards the internet,
the target is the E nine network appliance, so all the traffic from the application server is not destined
towards The VPC will first go towards the network appliance.
Now at a network appliance level, you have a local route over here and you have a0000 which goes towards
the Internet gateway.
So Application Server first sends the traffic destined towards the Internet gateway to the network Appliance.
Network Appliance will inspect the traffic and then it will send the traffic to the Internet gateway.
So this is one part.
The second part to consider here is the route at the Internet gateway level as well.
And within here, what you can define is any traffic that goes towards the subnet of the application
server.
So if you see the site, that block is 1077 2.0 slash 24, which you can see over here, any traffic
that goes towards the subnet, one should go to the E nine of the network appliance.
So whatever in this network appliance has, this is where the traffic will go to.
All right.
So I hope with this at a high level overview, you understood the architecture on how this kind of a
setup can be implemented.
Now, there are certain challenges with this kind of architecture.
First, as we were discussing that the routing is done at an inner level of the network appliance.
For example, from this route we can identify that all the traffic that is going towards the Internet
is going towards the target of the INA of the network appliance.
This is what the first pointer denotes.
Now, when you have such kind of a route table, you will see issues related to high availability and
scaling.
For example, let's say that this network appliance went down.
This is nothing but an easy to instance.
What happens if this EC two instance went down?
Still, depending upon the route table, the traffic will go towards the INA.
So what you'll have to do if you launch one more network appliance EC two, you will have to change
the route table associated with the Internet gateway as well as that of the subnet of the application
server.
The second primary issue is scaling.
Since we have defined only one INA.
What happens if there are ten instance of the network appliance that are running?
So this is also one of the issues that you will face here.
So in order to overcome this, A has introduced a new type of load balances call as the gateway load
balancers, which allows you to deploy scale and manage the virtual appliances easily.
So now in this type of architecture, you have multiple set of network appliances and what you do you
create a gateway load balancer.
And this gateway load balancer also has a specific endpoint.
So all the traffic from the application server, let's assume towards the Internet will go towards the
gateway load balancer.
Endpoint, which in turn forwards it to the Gateway load balancer.
And this gateway load balancer can go ahead and distribute the traffic to multiple set of network appliances
that are running.
Now in this type of architecture, things are much more simpler.
You have high availability since there are multiple set of network appliances and you do not really
need to worry about the scaling issues as well.
Now, discussing about the Gateway load balancer, there is one very important point to note is that
in order to make use of the Gateway load balancer, the appliances needs to support the genic protocol.
For example, you see that the EC2 instances through the Gateway Load Balancer endpoint are sending
the traffic to the Gateway load balancer.
Now this gateway load balancer and network appliance also needs to communicate, and this is the reason
why the protocol needs to be supported.
So the idea is that whatever traffic that has been received from the EC two instances, it will be encapsulated
using the Geneve.
So this is one point that you need to keep in mind.
So this is a very high level overview about the gateway load balances and with this will conclude today's
video.