Tutorial / Cram Notes

Amazon Web Services (AWS) is a comprehensive, evolving cloud computing platform provided by Amazon. Among its various services, AWS offers a robust set of networking capabilities that are essential for designing and operating a network within the AWS ecosystem. Here we’ll discuss some of the key AWS networking concepts, which are crucial for those preparing for the AWS Certified Solutions Architect – Professional (SAP-C02) exam.

Amazon Virtual Private Cloud (Amazon VPC)

Amazon VPC is a service that allows you to launch AWS resources into a virtual network that you’ve defined. This virtual network closely resembles a traditional network that you’d operate in your own data center, with the benefits of using the scalable infrastructure of AWS.

  • Subnets: Within an Amazon VPC, you can create subnets, which are segments of the VPC’s IP address range where you can place groups of isolated resources.
  • Route Tables: Each subnet must be associated with a route table, which controls the routing of traffic between the subnet and other network destinations.
  • Internet Gateways and NAT Gateways: To connect the VPC to the internet and support outbound traffic, you can use an Internet Gateway. A NAT Gateway enables instances in a private subnet to connect to services outside the VPC without exposing those instances to incoming internet traffic.
  • Security Groups and Network ACLs: Security groups act as a virtual firewall for your instances to control inbound and outbound traffic, while network ACLs serve as a firewall for associated subnets, providing a layer of security at the subnet level.

AWS Direct Connect

AWS Direct Connect makes it easy to establish a dedicated network connection from your premises to AWS. This can reduce network costs, increase bandwidth throughput, and provide a more consistent network experience than internet-based connections.

  • Dedicated Connection: This involves installing a physical cable between your data center and an AWS Direct Connect location.
  • Hosted Connection: This is provided by AWS Direct Connect partners and might be a more flexible and cost-effective option if you don’t require the full bandwidth of a dedicated connection.

AWS VPN

The AWS VPN service provides a secure and private connection between your network or device and the AWS global network. It comes in two forms:

  • Site-to-Site VPN: Connects your on-premises network to your Amazon VPC.
  • Client VPN: A managed client-based VPN service that allows you to securely access your AWS resources and resources in your on-premises network.

Transitive Routing

By default, Amazon VPC does not allow transitive routing; this is the ability to route traffic between two spokes through a common hub. This means that if you have multiple VPC peering connections, the VPCs cannot route traffic between each other unless directly peered. To overcome this, you could set up an overlay network using a transit VPC with VPN appliances, or make use of AWS Transit Gateway which simplifies the network architecture and allows for transitive routing between all connected VPCs, on-premises data centers, and remote offices.

AWS Transit Gateway

AWS Transit Gateway is a service that enables customers to connect their Amazon Virtual Private Clouds (VPCs) and their on-premises networks to a single gateway. It provides a hub-and-spoke model, which simplifies management and reduces operational costs. With Transit Gateway, each new connection only needs to be made to the Transit Gateway and not to every VPC.

AWS Container Services

AWS provides several container services that facilitate managing and scaling containerized applications:

  • Amazon Elastic Container Service (ECS): A highly scalable, high-performance container management service that supports Docker containers and allows you to run applications on a managed cluster of Amazon EC2 instances.
  • Amazon Elastic Kubernetes Service (EKS): Provides a managed Kubernetes service that makes it simple to deploy, manage, and scale containerized applications using Kubernetes on AWS.

Both ECS and EKS integrate well with AWS networking features, ensuring that containerized applications are able to leverage the full capabilities of the AWS network infrastructure, including VPCs, security groups, load balancers, and routing.

When preparing for the AWS Certified Solutions Architect – Professional exam, it’s essential to have a deep understanding of these networking services, how they interact with one another, and how they can be utilized to design scalable, secure, and resilient architectures on AWS. Knowing the scenarios to leverage each service and the best practices for implementation will be crucial topics covered in the exam scope.

Practice Test with Explanation

True or False: In Amazon VPC, subnets can span multiple Availability Zones.

  • True
  • False

Answer: False

Explanation: In Amazon VPC, a subnet must reside entirely within one Availability Zone and cannot span across multiple Availability Zones.

What does Amazon VPC stand for?

  • Virtual Private Cloud
  • Virtual Public Compute
  • Variable Performance Computing
  • Virtual Private Compute

Answer: Virtual Private Cloud

Explanation: Amazon VPC stands for Virtual Private Cloud, which allows you to provision a logically isolated section of the AWS cloud where you can launch AWS resources in a virtual network that you define.

Which AWS service is used to establish a dedicated network connection from an on-premises network to AWS?

  • AWS Direct Connect
  • AWS VPN
  • Amazon Connect
  • Amazon VPC Peering

Answer: AWS Direct Connect

Explanation: AWS Direct Connect is a service that enables you to establish a dedicated network connection from your premises to AWS.

True or False: AWS VPN can be used to establish a Hardware VPN connection between an Amazon VPC and an on-premises network.

  • True
  • False

Answer: True

Explanation: AWS VPN includes the option for creating a Hardware VPN connection, which establishes a secure connection between your network and your Amazon VPC.

Which of the following statements about transitive routing through AWS VPC peering is correct?

  • AWS supports transitive routing for VPC peering connections.
  • AWS does not support transitive routing for VPC peering connections.
  • Transitive routing is automatically enabled for all VPC peering connections.

Answer: AWS does not support transitive routing for VPC peering connections.

Explanation: AWS does not support transitive routing for VPC peering connections, meaning that a VPC cannot route traffic between two other peered VPCs.

Which of the following container services is managed by AWS?

  • Amazon ECS
  • Docker Swarm
  • Kubernetes
  • All of the above

Answer: Amazon ECS

Explanation: Amazon ECS (Elastic Container Service) is a fully managed container orchestration service provided by AWS.

True or False: In AWS, security groups operate at the instance level, whereas network access control lists (ACLs) operate at the subnet level.

  • True
  • False

Answer: True

Explanation: Security groups in AWS act as a virtual firewall for instances, and network ACLs provide a layer of security for the subnets within a VPC.

Which of the following is a benefit of using AWS Direct Connect?

  • Reduced internet bandwidth usage
  • Improved latency and network performance
  • Consistent network experience
  • All of the above

Answer: All of the above

Explanation: AWS Direct Connect provides a private connection to AWS, which can reduce internet bandwidth costs, improve latency and provide a more consistent network experience than internet-based connections.

What is the purpose of an Internet Gateway in AWS?

  • To allow instances in a VPC to access the internet
  • To enable direct, private connectivity to AWS from an on-premises environment
  • To interconnect multiple VPCs within the same AWS region

Answer: To allow instances in a VPC to access the internet

Explanation: An Internet Gateway enables resources within your VPC to connect to the internet and vice versa.

True or False: AWS Fargate is a serverless compute engine for containers that works with both Amazon ECS and EKS.

  • True
  • False

Answer: True

Explanation: AWS Fargate is a serverless compute engine that allows you to run containers without having to manage servers or clusters that works with Amazon ECS and EKS (Elastic Kubernetes Service).

Interview Questions

What is Amazon VPC and why is it considered a fundamental component of AWS networking?

Amazon VPC (Virtual Private Cloud) is a service that lets you launch AWS resources in a logically isolated virtual network that you define. It’s fundamental because it provides the networking layer of Amazon EC2, allowing you to control network configurations, IP address ranges, subnetting, route tables, network gateways, and security settings.

Can you explain the differences between AWS Direct Connect and AWS VPN?

AWS Direct Connect is a network service that provides an alternative to using the internet to utilize AWS services by establishing a dedicated network connection from your premises to AWS. On the other hand, AWS VPN provides secure and private communication tunnels from your network to AWS over the internet. Direct Connect is usually preferred for stable and consistent network performance, while VPN is used for quick, cost-effective, encrypted connections.

How does transitive routing work within a VPC, and how should one set it up?

Transitive routing allows network traffic to pass between different VPCs or VPN connections via a central hub. In AWS, transitive routing is not natively supported for VPC peering, so to achieve it, you must use a Transit Gateway or implement a network appliance in a VPC that acts as a router.

Can you describe the function and benefits of AWS Transit Gateway?

AWS Transit Gateway acts as a network hub that simplifies the connectivity between VPCs, AWS VPNs, and on-premises networks. The main benefits include central management, reduced complexity, and the ability to scale connectivity across thousands of VPCs and networks without managing individual peering connections.

What is the purpose of Network Access Control Lists (NACLs) in an Amazon VPC?

Network Access Control Lists (NACLs) are stateless, layer 4 packet filters that provide a rule-based approach to control inbound and outbound traffic at the subnet level within an Amazon VPC. They serve as an additional layer of security to the security groups, which are stateful and operate at the instance level.

In AWS, what is the difference between a NAT Gateway and a NAT Instance?

A NAT Gateway is a managed service provided by AWS that allows instances in a private VPC subnet to connect to services outside the VPC (e.g., the internet) but prevents external services from initiating connections with those instances. A NAT Instance is an EC2 instance configured to perform Network Address Translation. NAT Gateways are more scalable, highly available, and managed by AWS, while NAT Instances are more customizable but require manual management and scaling.

Explain how Elastic Load Balancing (ELB) works in the context of an AWS VPC.

Elastic Load Balancing automatically distributes incoming application traffic across multiple targets, such as EC2 instances, containers, and IP addresses, within an AWS VPC. It improves the fault tolerance of your applications by ensuring that the end-users’ requests are routed to healthy instances, supporting different load balancing mechanisms (e.g., round robin, least outstanding requests).

When would you recommend the use of AWS PrivateLink in a VPC?

AWS PrivateLink should be recommended when private connectivity is required between VPCs, AWS services, and on-premises applications. It securely connects services across a VPC endpoint without needing to use public IPs or traverse the public internet, thus enhancing security and possibly reducing bandwidth costs.

What are the best practices for designing a VPC for high availability and fault tolerance?

Best practices include using multiple Availability Zones by spreading resources across them, creating public and private subnets, and ensuring critical components (such as NAT Gateways, EC2 instances, RDS instances) are replicated across these zones. Additionally, the design should incorporate Elastic IP addresses, failover configurations, and perhaps Multi-AZ deployment for RDS and other services.

How does AWS Fargate enhance the networking of container-based applications?

AWS Fargate is a serverless compute engine for containers that works with Amazon ECS and EKS. For networking, Fargate removes the need to manage the underlying EC2 instances, allowing you to focus on designing and managing your applications. It integrates with Amazon VPC, enabling you to run containers in a secure, isolated environment, with support for VPC features like security groups, NACLs, and route tables.

Can you explain briefly what AWS Outposts is and how it fits into AWS’s networking portfolio?

AWS Outposts is a fully managed service that brings AWS infrastructure and operating models on-premises, allowing a truly consistent hybrid experience. It extends AWS networking capabilities to your own datacenter, co-location space, or on-premises facility to support applications with low-latency or local data processing requirements while still having seamless access to the full range of AWS services in the cloud.

Describe how AWS Cloud Map can assist with service discovery in a large, microservices-driven architecture.

AWS Cloud Map is a cloud resource discovery service that allows developers to define custom names for application resources such as databases, queues, microservices, or other cloud services. It simplifies the management of resource locations, routes, and names, making it straightforward for services within a microservices architecture to discover and communicate with each other reliably, even as resources change and scale.

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Elias Rintala
5 months ago

This blog post on AWS networking concepts is a goldmine for anyone prepping for the SAP-C02 exam! Amazon VPC is particularly well-explained.

Frank Henden
7 months ago

Could someone explain how AWS Direct Connect differs from AWS VPN?

Helin Kihle
6 months ago

How essential is transitive routing in a multi-VPC architecture?

Alicia Diez
7 months ago

Interesting read on AWS container services. AWS Fargate seems convenient for serverless container deployment.

Nash Steenkamp
6 months ago

Great post! Helped me understand transitive routing better.

Joey Herrera
6 months ago

The tutorial on Amazon VPC kept it simple and easy to grasp. Thanks!

Wyatt Patterson
6 months ago

The blog post really clarifies the difference between AWS Direct Connect and AWS VPN.

Balvan Kumar
7 months ago

Highly recommend this post for anyone studying for the SAP-C02.

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