-: Let's get into the last load balancer,
which is Network Load Balancers,
and they are layer 4 balancers
that means that they allow you to forward TCP
or UDP based traffic to your instances.
So it's lower level.
It allows you to handle millions of requests per second.
So they're extremely high performance,
and the latency is a lot less than for the ALB.
So just some numbers to give you an idea.
400 milliseconds would be some average latency
for an application of the balancer.
Whereas for a Network Load Balancer,
we get around 100 milliseconds of latency.
The NLBs also very different
because they expose one static IP per availability zone
on the outside.
And that is very helpful
when you want to white-list specific IP.
And also they support assigning elastic IPs
instead of getting the ones given by the NLB itself.
So that means that you can use NLB when you want
to have two entry points,
for example,
that are dedicated specific IP for your application,
and then the NLB will forward that traffic
into your EC2 instances.
That is different from the ALB or CLB,
which did not have a static IP, but had a static host name.
Now the NLB, the use case,
in the scenario questions,
is going to be around when you want to extreme performance,
or you want TCP or UDP level traffic.
And for the hands-on that we're going to do very, very soon,
the NLBs are not included in the AWS free tier.
So if you do the hands-on with me,
then you will pay some money.
So if you don't want to pay any money,
then don't do the hands-on with me, very simple.
Now the Network Load Balancer is layer 4,
and so what that means is
that's your target groups, just like before,
it can be EC2 instances,
but now,
your TCP based traffic will reach your target groups.
And so it could be from the external,
and we can also have some rules
around how to redirect to your target groups, okay.
So what can Network Load Balancer send traffic to?
Well, we can have different target groups.
The first one is EC2 instances.
So we can register EC2 instances with target groups,
and then the Network Load Balancer will know
how to send traffic to them.
That's very intuitive.
The second one is by IP addresses.
So we can specify fixed, static, private IP addresses,
and have the NLB send traffic directly to them.
Why would we do that?
Well, for EC2 instances, it's a bit of an overkill,
but if you had a server
on your own data center, for example,
you could use a network balancer,
preferably a server with a private IP
and use that as is.
So this is the second option.
And the third option is Application Load Balancer.
So it is possible for you to chain together
a Network Load Balancer and an Application Load Balancer.
So why would you do that?
Well, maybe you want to leverage the feature of the NLB
to have fixed static IPs.
And so therefore
you want to have fixed static IP at the NLB level,
but you want to leverage the ALB
for all its HDP related features,
such as rules and so on, okay.
So that's it for the Network Load Balancer.
Now I will see you in the next lecture to create one.