Chapter 9 - VPC overview

Question 1

VPC

Answer 1

A logical data center inside AWS.

It consists of:

• internet gateways
• virtual private gateways,
• route tables
• network access control lists,
• subnets
• security groups.
• Remember that one subnet is always in one availability zone.
• You can’t have a subnet that spans multiple availability zones.

Peerings:

• So this allows you to connect one VPC with another via a direct network route using private IP addresses,
• Instances behave as if they were on the same private network,
• You can peer VPCs with other AWS accounts
• As well as other VPCs in the same account.
• Peering is always done in a star configuration.
• You can’t have transitive peering.
• You can peer VPCs between regions.

Question 2

NAT gateways

Answer 2

• We remember that it is redundant inside the availability zones.
• it does give you sufficient network throughput.
• You don’t need to go in and patch the operating system or anything for your NAT gateway
• It’s not associated with any security groups
• It is automatically assigned a public IP address when you create it.
• If you have resources in multiple availability zones and they share in that gateway in the event that that NAT gateway’s availability zone is down, then the resources in the other availability zones are going to lose internet access.
• To create an availability zone independent architecture, you need to create NAT gateways in each availability zone.

Question 3

AWS PrivateLink

Answer 3

• If you see a question asking about peering VPCs to tens, hundreds, and thousands of customer VPCs, I want you to think of AWS PrivateLink.
• It doesn’t require VPC peering.
• There’s no route tables, NAT gateways, internet gateways, etc.
• But it does require Network Load Balancer on the service VPC.
• It requires an ENI on the customer VPC

Question 4

Transit gateways

Answer 4

• Transit gateway works with Direct Connect as well as VPN connections.
• • It supports IP multicast,which is basically a way of allowing a host to send a single packet to thousands of hosts across a routed network.
• going into the exam if you just see a question about simplifying network topology or they’re talking about IP multicasting, just think of transit gateway.
• Transit gateway’s fantastic technology that basically stops you from having to have all these different
• peering connections, etc.

Question 5

VPN Hub

Answer 5

it’s a way of simplifying your VPN network topology.