‫So now let's talk about the newest kind of load balancer
‫called the gateway load balancer.
‫So it is used to deploy
‫scale and manage your fleet of
‫third-party network, neutral appliances in AWS.
‫And it will explain what that means in a second.
‫So you would use a gateway load balancer
‫if you want it to have all traffic,
‫of your network
‫to go through a firewall that you have,
‫or an intrusion detection and prevention system.
‫So IDPs or a deep packet inspection system,
‫or you want to, to modify some payloads,
‫but at the network level. Okay.
‫So let's have a look
‫to make it very simple with a diagram.
‫So, say have users and these users
‫are used to access your applications.
‫Now we know that their users, for example,
‫can access our applications directly
‫using a load balancer,
‫for example, and an application, or balancer.
‫And then the traffic goes directly
‫from the users to the ALB, to the application.
‫But what if you wanted
‫all that network traffic
‫to be inspected first,
‫before being sent to your application,
‫you have actually deployed
‫a bunch of third party virtual appliances,
‫for example, EC2 instances
‫that you want all traffic to go through
‫before the traffic reaches your application.
‫So to do so, it used to be very complicated,
‫but now with a gateway load balancer,
‫it is actually very simple.
‫So you're going to create a gateway load balancer
‫and what's going to happen is that
‫behind the scenes.
‫The route tables have to be updated in your VPC.
‫Now this is quite advanced
‫and it's more in the networking side,
‫but bear with me.
‫So the route tables are modified.
‫And now what happens at all users traffic
‫first goes through a gateway load balancer
‫and the gateway load balancer
‫will then spread that traffic across
‫a target group of your virtual appliances.
‫And so all the traffic will reach these appliances
‫then the appliances will analyze the traffic,
‫you know, what do whatever they have to do.
‫So for example, firewall again,
‫intruder detection and so on.
‫And then if they're happy with it,
‫they can send it back to the gateway load balancer.
‫If they're not happy with it,
‫they can just drop the traffic. For example,
‫for a firewall, you would drop the traffic,
‫but if it's accepted,
‫then it goes through your gateway load balancer again,
‫and then the gateway load balancer
‫Will forward a traffic
‫all the way to your application
‫and for your application. This is transparent.
‫The only thing that has happened now
‫is that all the traffic
‫has gone through the gateway load balancer.
‫And your third-party patrol appliances,
‫for you to analyze all that network traffic
‫and possibly drop it.
‫So this is the power of the gateway load balancer
‫is to analyze network traffic and so on.
‫So how does that work?
‫Well, the gateway load balancer
‫operates at a lower level than all
‫the load balancers we've seen.
‫This is layer three,
‫which is a network layer for IP packets.
‫So what's going to happen
‫is that you're gateway load balancer
‫has two functions.
‫The first one is a transparent network gateway
‫because all the traffic
‫will in your VPC will go through a single entry
‫and a single exit,
‫which is going to be your gateway load balancer,
‫and then is going to be a load balancer
‫because it distributes that traffic
‫across a sets of virtual appliances
‫and your target group.
‫So this is basically
‫what you remember about the gateway load balancer.
‫And finally, if you see on an exam,
‫that's you want to use the GENEVE protocol
‫on ports 6081
‫Then again, this will be right away
‫if you getaway load balancer.
‫So hopefully this diagram makes sense. Now,
‫what can be target groups, for the gateway load balancers
‫So this is your third party appliances.
‫They can either be EC2 instances
‫and you register them by instance ID,
‫or they can be IP addresses.
‫In that case, they must be private IPs.
‫And for example, if you are running
‫these virtual appliances on your own network,
‫on your own data center,
‫then you can register them by IP manually.
‫So that's it for the gateway load balancer.
‫It is extremely difficult to do a hands-on on it.
‫So I will skip one. Okay.
‫But just so you know, again,
‫the most important thing to remember
‫is that one diagram on the right-hand side,
‫if you understand this diagram,
‫you understand, getaway load balancers.
‫And I don't think
‫any deep dive question will be asked on it
‫just at a high level,
‫what it means and how it works. Okay.
‫So that's it.
‫I hope you liked it,
‫and I will see you in the next lecture.