AWS Global Infrastructure: Availability Zones, Regions, Edge Locations, Regional Edge Caches, Local Zones, Wavelength Zones, and Outposts

Global infrastructure

Amazon Web Services is a global public cloud provider, and as such, it has to have a global network of infrastructure to run and manage its many growing cloud services that support customers around the world. In this post, we’ll take a look at the components that make up the AWS Global Infrastructure.

The components are:

  • Availability Zones (AZs)
  • Regions
  • Edge Locations
  • Regional Edge Caches
  • Local Zones
  • Wavelength Zones
  • Outposts

If you are deploying services on AWS, you’ll want to have a clear understanding of each of these components, how they are linked, and how you can use them within your solution to YOUR maximum benefit. Let’s take a closer look.

AWS Global Infrastructure: Availability Zones

Availability Zones and Regions are closely related.

AZs are essentially the physical data centers of AWS. This is where the actual compute, storage, network, and database resources are hosted that we as consumers provision within our Virtual Private Clouds (VPCs). A common misconception is that a single availability zone is equal to a single data center. This is not the case. In fact, it’s likely that multiple data centers located close together form a single availability zone.

Each AZ will always have at least one other AZ that is geographically located within the same area, usually a city, linked by highly resilient and very low latency private fiber-optic connections. However, each AZ will be isolated from the others using separate power and network connectivity that minimizes impact to other AZs should a single AZ fail.

These low latency links between AZs are used by many AWS services to replicate data for high availability and resilience purposes. For example, when RDS (Relational Database Service) is configured for ‘Multi-AZ’ deployments, AWS will use synchronous replication between its primary and secondary database and asynchronous replication for any read replicas that have been created.

Often, there are three, four, or even five AZs linked together via these low latency connections. This localized geographical grouping of multiple AZs, which would include multiple data centers, is defined as an AWS Region.

AWS Availability Zones

Multiple AZs within a region allows you to create highly available and resilient applications and services. By architecting your solutions to utilize resources across more than one AZ ensures that minimal or no impact will occur to your infrastructure should an AZ experience a failure, which does happen).

Anyone can deploy resources in the cloud, but architecting them in a way that ensures your infrastructure remains stable, available, and resilient when faced with a disaster is a different matter. Making use of at least two AZs in a region helps you maintain high availability of your infrastructure and it’s always a recommended best practice.

AWS Global Infrastructure: Regions

As we now know, a Region is a collection of availability zones that are geographically located close to one other. This is generally indicated by AZs within the same city. AWS has deployed them across the globe to allow its worldwide customer base to take advantage of low latency connections. Every Region will act independently of the others, and each will contain at least two Availability Zones.

For example, if an organization based in London was serving customers throughout Europe, there would be no logical sense to deploy services in the Sydney Region simply due to the latency response times for its customers. Instead, the company would select the region most appropriate for them and their customer base, which may be the London, Frankfurt, or Ireland Region.

Having global regions also allows for compliance with regulations, laws, and governance relating to data storage (at rest and in transit). For example, you may be required to keep all data within a specific location, such as Europe. Having multiple regions within this location allows an organization to meet this requirement.

Similarly to how utilizing multiple AZs within a region creates a level of high availability, the same can be applied to utilizing multiple regions. Depending on the level of business continuity you require, you may choose to architect your AWS environment to support your applications and services across multiple regions, should an entire region become unavailable, perhaps due to a natural disaster.

You may want to use multiple regions if you are a global organization serving customers in different countries that have specific laws and governance about the use of data. In this case, you could even connect different VPCs together in different regions. Learn more from AWS about Multiple Region Multi-VPC Connectivity.

To learn more about the AWS certifications offered by Cloud Academy, read our post, The 12 AWS Certifications: Which is Right for You are Your Team, or contact one of our knowledgeable reps for more information.

The number of regions is increasing year after year as AWS works to keep up with the demand for cloud computing services. At the time of publishing this article (August 2023), there are currently 32 Regions and 102 Availability Zones, with 4 additional Regions and 12 additional AZs planned.

Interestingly, not all AWS services are available in every region. This is a consideration that must be taken into account when architecting your infrastructure. Some services are classed as global services, such as AWS Identity & Access Management (IAM) or Amazon CloudFront, which means that these services are not tied to a specific region.  However, most services are region-specific, and it’s down to you to understand which services are available in which region. 

AWS logically groups its Regions into larger geographical areas for ease of management. For example, the N. Virginia and Ohio Regions fall under the geographic location of US East.

Although regions are grouped together in this way, every single region is independent of other regions.

The AWS GovCloud is an isolated region in the U.S. that is only available to U.S. government agencies and organizations in government-regulated industries, which must meet strict requirements. 

Region and Availability Zone Naming Conventions

AWS has a specific naming convention for both Regions and Availability Zones.

Depending on where you are viewing and using the Region name, it can be represented as two different names for the same Region.

Regions have both a ‘friendly’ name, indicating a location that can be viewed within the Management Console and a Code Name that is used when referencing regions programmatically, for example when using the AWS CLI.

As you can see, the name in the first column is easier to associate to than that of the Code Name.

Availability Zones are always referenced by their Code Name, which is defined by the AZs Region Code Name that the AZ belongs to, followed by a letter. For example, the AZs within the eu-west-1 region (EU Ireland), are:

  • eu-west-1a
  • eu-west-1b
  • eu-west-1c

AWS EU Ireland Region

An interesting point to be aware of here is that AWS maps these AZ letter identifiers to different physical AZs for different AWS accounts. This ensures that there is a more even distribution of resources across all AZs within a Region.

AWS EU Ireland Region

If you have multiple AWS accounts and you try to coordinate resources within the same AZ by selecting the same AZ Code Name, this may not necessarily mean that those resources are physically located within the same AZ as you can see in the image above.

AWS Global Infrastructure: Edge Locations

Edge Locations are AWS sites deployed in major cities and highly populated areas across the globe. They far outnumber the number of availability zones available.

While Edge Locations are not used to deploy your main infrastructures such as EC2 instances, EBS storage, VPCs, or RDS resources like AZs, they are used by AWS services such as AWS CloudFront and AWS Lambda@Edge (currently in Preview) to cache data and reduce latency for end-user access by using the Edge Locations as a global Content Delivery Network (CDN).

As a result, Edge Locations are primarily used by end users who are accessing and using your services.

For example, you may have your website hosted on EC2 instances and S3 (your origin) within the Ohio region with a configured CloudFront distribution associated. When a user accesses your website from Europe, they would be re-directed to their closest Edge Location (in Europe) where cached data could be read on your website, significantly reducing latency.

AWS Global Infrastructure: Regional Edge Cache

In November 2016, AWS announced a new type of Edge Location, called a Regional Edge Cache. These sit between your CloudFront Origin servers and the Edge Locations.  A Regional Edge Cache has a larger cache-width than each of the individual Edge Locations, and because data expires from the cache at the Edge Locations, the data is retained at the Regional Edge Caches.

Therefore, when data is requested at the Edge Location that is no longer available, the Edge Location can retrieve the cached data from the Regional Edge Cache instead of the Origin servers, which would have a higher latency.

AWS Global Infrastructure: Regional Edge Cache

AWS Global Infrastructure: Local Zones

In 2022, Amazon announced that it had launched its first 16 Local Zones, a new type of infrastructure deployment designed to place core AWS Compute, Storage, Networking, and Database services near highly populated areas such as major cities that do not already have an AWS Region nearby. For example, the eastern United States has two Regions: us-east-1 in northern Virginia and us-east-2 in Ohio. However, there are also very large metropolitan areas around Boston, New York City, Philadelphia, Atlanta, and Miami, all of which are 100 miles or more from the data centers in that Region’s nearest Availability Zones. AWS Local Zones allow customers in these areas to deploy resources and applications that require single-digit millisecond latency that would otherwise not be attainable given the geographic distance to the nearest Regions.

They are also useful where data residency requirements may dictate that data be stored within certain geographic boundaries.

All AWS Local Zones are connected to a parent Region, allowing you to seamlessly connect to all other AWS services via a secure, dedicated high-speed connection. AWS Local Zones are currently available in a total of 33 metropolitan areas, with an additional 19 planned in the future. To use Local Zones, you must first enable them within your AWS account. After that, all Local Zones will be listed alongside the Availability Zones within that Region and can be selected when deploying everything from VPC subnets, to EC2 instances and EBS volumes, to ECS and EKS clusters.

In August 2023, AWS announced Dedicated Local Zones, which offer dedicated, fully managed infrastructure that is built for the exclusive use of a specific customer or community. Dedicated Local Zones can be deployed in an existing on-premises data center or other locations that may be dictated by a customer or community’s requirements to comply with security or other data sovereignty regulations for mission-critical and other sensitive workloads. These are especially useful in the public sector and other industries where strict governance controls are necessary to comply with local laws and regulations.

AWS Global Infrastructure: Wavelength Zones

Much like AWS Local Zones, AWS Wavelength Zones also place core AWS services closer to large end user bases and are connected to a parent Region via a secure, dedicated high-speed connection. However, AWS Wavelength Zones are embedded within 5G mobile broadband networks and are deployed within the data centers of large telecommunications providers. Deploying AWS resources such as VPC subnets, EC2 instances, and EBS volumes to an AWS Wavelength Zone allows end users to connect to these resources without ever leaving the mobile provider’s network. By reducing the number of network hops and eliminating the need for any traffic to traverse the public internet, developers can offer ultra-low latency and increased reliability for 5G applications such as live video streaming and interactive gaming. AWS Wavelength Zones are currently available through Verizon in the United States, KDDI in Japan, SK Telecom in South Korea, Vodafone in the UK and Germany, and Bell in Canada.

AWS Global Infrastructure: Outposts

AWS Outposts brings the capabilities of the AWS cloud to your on-premises data center. This includes the same hardware used by AWS within their data centers, allowing you to use native AWS services, including the same tools and APIs you would use when running your infrastructure within AWS. Outposts are available as 1U or 2U rack-mountable servers, or as entire 42U racks that can be scaled to deployments of up to 96 racks. Outposts may be connected to AWS using either a Direct Connect or VPN connection. Outposts allow you to run AWS services such as EC2, ECS, EKS, S3, RDS, and EMR on-premises. Customers can also make use of PrivateLink gateway endpoints to securely and privately connect to other services and resources, such as DynamoDB. There are a wide number of EC2 instance types available on AWS Outposts. These include M5, C5, and R5 instances, as well as storage options for EBS volumes, local disks, and local instance storage.

Because AWS Outposts are fully managed, you do not need to maintain a level of patch management across your infrastructure or worry about installing or updating any software. AWS will ensure your Outposts are patched and updated as needed.

I hope that this post has provided some clarity around the AWS global infrastructure of Availability Zones, Regions, Edge Locations, Regional Edge Caches, Local Zones, Wavelength Zones, and Outposts.

Understanding what each of these components can allow you to do will help you architect a resilient, highly available, secure, and low latency solution for you and your customers.

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