Hi guys welcome to another exam cram.
And this time we'll cover networking in quite a lot of detail.
So let's have a look at what we covered.
You learned about virtual private cloud that a VPC is a virtual network dedicated to your accounts.
It's analogous to having your own datacenter inside AWS and it's logically isolated from other networks
in the AWS cloud.
You get complete control over your virtual networking environment so you can create your own IP ranges
subnets configuration route tables and gateways you can then launch your own resources such as EC2
instances into your VPC when you create the VPC.
You have to create a CIDR block so as a classless inter domain routing block and that's an IP address
range and we did that in the hands on lab as well. A VPC spans all Availability Zones in the region.
You have full control over to your resources.
You get up to five by default.
You can change that but that's per region and a default VPC is created in each region with a subnet
in each AZ, that's by default.
We learned about security groups and network ACLs.
So just remember the key differences here.
Security group is operating at the instance level network ACLs operate at the subnet level.
Security groups support allow rules only. A network ACL supports allow and deny rules.
Security groups are stateful, network ACLs are stateless.
That's about all you need to know for the cloud practitioner exam.
We learned about addresses as well so the different types of IP address a public IP address allows you
to be able to connect to the Internet they used in public subnets and you lose them when the instance
is stopped a private IP address is used in public and private subnets.
So you always have a private IP address and it's retained when instances stopped.
If you need to keep your public IP you use an elastic IP and you don't get charged unless you've created
one where you've allocated once your account but you're not using it.
In that case you do actually pay. Elastic IP addresses can also be moved between instances and elastic
network adapters you learned about NAT instances and NAT gateways as well.
So remember the what we're trying to do here with a net instance is enable an EC2 instance in a private
subnet to be able to access the Internet and we can use a NAT instance or a NAT gateway. The NAT instance
is managed by you.
It's an EC2 instance that you manage and the NAT gateway is fully managed by AWS.
If you have a NAT instance you've got to scale it yourself by changing instance types whereas a NAT
Gateway is elastically scalable.
The NAT instance does not have HA whereas the Gateway does have HA.
For most cases you're going to use a NAT Gateway and those are the facts that you need to know for the
cloud practitioner exam.
We also learnt about the different options for securely connecting to a VPC.
So firstly there's the managed VPN virtual private network. Very easy to set up uses the public Internet.
So in terms of performance it's not necessarily reliable. Direct connect is high bandwidth low latency
and very reliable but it takes time to set up and costs money.
You only use it if you have high bandwidth requirements and then the VPN cloud hub is another way that
you use VPN but it connects in multiple sites to AWSs and you could also use third party software.
So a bit more about Direct Connect remember that this is a network service that's an alternative to
using the Internet to connect to customers network and it's a private network connection you can use
it to create a hybrid cloud- key exam question. The data is transmitted through private connections
between AWS and the customers data center and you'll use this for reducing cost when you have large
volumes of traffic and increasing reliability and performance and increasing bandwidth and having predictable
bandwidth and you do decrease latency which is like the delay on the link.
So overall better for performance you get charged by the port hours and you can choose from one gigabits
per second or 10 Gbps or if you use an AWS Direct Connect partner you can choose one of these different bandwidths
as well and if there's anything there that doesn't make sense.
Please make sure you go back to the relevant lesson and watch the lesson fully and then you can also
check the training Notes and links that we provide in the downloads to get further information about
these different subjects.