View source for AWS Solutions Architect/training/Section 5: Advanced Amazon VPC

*42. Introduction
*43. The AWS Global Infrastructure - connected by high-speed backbone network between the regions.
**Made of 26+ regions. Each region has two or more Availability Zones - for redundancy. An availability zone can be thought of as a physical data center. Each data center has redundant power sources and redundant networking.
**AWS Outposts - extends AWS services into dedicated hardware in '''your''' data center or corporate location. For using AWS services on-premises. For using AWS APIs on-premises.
**AWS Local  Zone - exxtends the AWS Availability Zone closer to end-users for lower latency. I guess it's like an Availability Zone without the full-fledged characteristics of a Data Center?
**AWS Wavelength Zone - extends AWS using 5G wireless. For singled-digit ms latency to mobile device users.
**AWS CloudFront is a CDN with 13+ Regional Edge Caches and 400+ Edge locations.
*44. Defining VPC CIDR Blocks
**8 host bits = 256 addresses /24 subnet mask 255.255.255.0
**16 host bits = 65,536 addresses /16 subnet mask 255.255.0.0
**12 host bits = 4096 addresses /20 subnet mask <ref>https://en.wikipedia.org/wiki/Classless_Inter-Domain_Routing#IPv4_CIDR_blocks</ref>
**Cannot increase or decrease the size of your CIDR block once it's defined (You'd have to create and migrate to a new VPC)
**Recommended to use RFC 1918 ranges <ref>The Internet Assigned Numbers Authority (IANA) has reserved the following three blocks of the IP address space for private internets:
<pre>
10.0.0.0        -   10.255.255.255  (10/8 prefix)
172.16.0.0      -   172.31.255.255  (172.16/12 prefix)
192.168.0.0     -   192.168.255.255 (192.168/16 prefix)
</pre>

We will refer to the first block as "24-bit block", the second as 
"20-bit block", and to the third as "16-bit" block. Note that (in 
pre-CIDR notation) the first block is nothing but a single class A 
network number, while the second block is a set of 16 contiguous 
class B network numbers, and third block is a set of 256 contiguous 
class C network numbers.</ref>
**https://docs.aws.amazon.com/vpc/latest/userguide/subnet-sizing.html
**Solarwinds has an interactive (not obvious) calculator https://www.solarwinds.com/free-tools/advanced-subnet-calculator and there's a similar calculator at https://www.site24x7.com/tools/ipv4-subnetcalculator.html 
*45. [HOL] Create a Custom VPC
*46. VPC Routing Deep Dive
*47. Security Groups and Network ACLs
*48. [HOL] Configure Security Groups and NACLs
*49. NAT Gateways and NAT Instances
*50. [HOL] Private Subnet with NAT Gateway
*51. Using IPv6 in a VPC
*52. [HOL] Configure IPv6
*53. VPC Peering
*54. [HOL] Configure VPC Peering
*55. VPC Endpoints
*56. [HOL] Create VPC Endpoint


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