Inter-VPC and multi-account connectivity (for example, VPC peering, Transit Gateway, VPN, third-party vendors, SD-WAN, multi-protocol label switching [MPLS])

What is VPC peering and how does it differ from using a Transit Gateway for inter-VPC connectivity?

VPC peering is a networking connection between two VPCs that enables you to route traffic between them using private IP addresses. It differs from using a Transit Gateway in that VPC Peering is a one-to-one relationship between VPCs, whereas Transit Gateway acts as a hub that can connect multiple VPCs and on-premises networks. Transit Gateway simplifies the management and scaling of network architecture.

When configuring VPC peering, what are limitations that you need to be aware of?

VPC peering has several limitations, including the non-transitive nature of the connection, meaning you cannot route traffic from one VPC to a third VPC through a peered connection. Peering is also region-specific, although inter-region peering is possible, it requires additional configuration. Overlapping IP address ranges cannot be used, and peering connections do not support edge to edge routing through a gateway or private connection.

How can one set up connectivity between multiple accounts using AWS Transit Gateway?

To set up connectivity between multiple accounts using AWS Transit Gateway, you need to create a Transit Gateway in one account and share it with other accounts using AWS Resource Access Manager (RAM). The invited accounts can then attach their VPCs to the shared Transit Gateway, enabling centralized management and connectivity among the VPCs across the various accounts.

What are some use cases for an AWS Site-to-Site VPN over Direct Connect, and when would you choose one over the other?

AWS Site-to-Site VPN is typically used for quick setup, encryption, and when there’s no requirement for dedicated bandwidth whereas Direct Connect is used when consistent, high throughput and a private, dedicated connection is needed. Choose VPN for cost-effective solutions and encryption needs, and Direct Connect for consistent performance and large data transfers.

Explain the difference between AWS Site-to-Site VPN connections and AWS Client VPN.

AWS Site-to-Site VPN allows secure connections between an on-premises network or branch office site to an Amazon VPC, ideal for connecting entire networks. AWS Client VPN, on the other hand, is for individual client-based access and allows users to connect to resources in AWS from any location using an OpenVPN-based VPN client. It’s typically used for remote workers.

What is MPLS, and why might a company choose to use it in conjunction with AWS services?

MPLS (Multi-Protocol Label Switching) is a protocol-agnostic routing technique that directs data from one network node to the next based on short path labels rather than long network addresses. Companies might choose to use MPLS for its performance, reliability, and traffic engineering capabilities, and they can integrate it within their AWS deployment for seamless connection with cloud resources, often using AWS Direct Connect in conjunction.

How does an SD-WAN solution benefit multi-account VPC connectivity?

SD-WAN (Software-Defined Wide Area Network) benefits multi-account VPC connectivity by providing a more flexible, cloud-friendly network solution. It allows for easy management of networking connections, including those across multiple VPCs and accounts, through software configuration rather than hardware setups. This results in easier scaling, improved bandwidth efficiency, and better performance for cloud applications.

When would you recommend using third-party vendors for networking solutions on AWS, instead of native AWS services?

Third-party vendors for networking solutions might be recommended when there is a need for specialized functionality that AWS native services do not provide, such as advanced WAN optimization, customized security requirements, or proprietary technology integration. Additionally, if a company is heavily invested in a particular vendor’s ecosystem or requires specific compatibility, third-party solutions can be integrated within AWS.

Discuss the deployment considerations for using AWS Transit Gateway in a large-scale enterprise environment.

Deployment considerations for using AWS Transit Gateway in a large-scale enterprise environment include ensuring adequate routing and scalability planning for connecting to multiple VPCs and on-premises networks. You would need to design for high availability and redundancy, as well as consider the routing tables, Transit Gateway policies, and the implications on network throughput. Cost management and monitoring are also important as the Transit Gateway can have a high number of routes and connections that impact pricing.

How do you ensure secure communication in VPC peering connections, especially when peer VPCs belong to different organizations?

Ensuring secure communication in VPC peering connections involves implementing network ACLs (Access Control Lists) and security group rules to control inbound and outbound traffic between peered VPCs. It’s crucial to establish clear and restrictive policies defining which traffic can traverse the peering connection. Additionally, strong IAM policies should be set for who can modify VPC peering connections, and regularly reviewing VPC flow logs can help monitor and audit the traffic for security purposes.