Here are ten things network engineers working with AWS infrastructure should know:

1. VPC Flow Logs: Utilizing VPC Flow Logs can help in troubleshooting connectivity issues and identifying security threats by providing detailed information about the traffic flowing in and out of your VPCs.

2. VPC Peering: Implementing VPC peering can enable communication between VPCs in the same or different AWS accounts, reducing the need for expensive VPN or Direct Connect setups.

3. Elastic Network Interfaces (ENIs): Leveraging ENIs allows you to create multiple network interfaces within an EC2 instance, providing flexibility in network configuration and enabling features like failover and traffic mirroring.

4. AWS Global Accelerator: Using AWS Global Accelerator can improve the performance and availability of your applications by routing traffic through the AWS global network infrastructure, optimizing the path between users and your application endpoints.

5. AWS Transit Gateway: Implementing AWS Transit Gateway simplifies network architecture by acting as a central hub for connecting multiple VPCs and on-premises networks, making it easier to manage and scale your network topology.

6. Network Access Control Lists (NACLs): Configuring NACLs as an additional layer of security can help control traffic at the subnet level, providing a stateless firewall that can deny or allow specific types of traffic.

7. AWS PrivateLink: Utilizing AWS PrivateLink allows you to securely access services hosted on AWS without exposing them to the public internet, reducing the attack surface and improving network security.

8. Elastic IP Addresses: Allocating Elastic IP addresses and associating them with EC2 instances can provide static public IP addresses, which can be useful for whitelisting, DNS configuration, and maintaining consistent network identity.

9. VPC Endpoints: Implementing VPC Endpoints enables private connectivity between your VPC and supported AWS services, reducing the need for internet gateways, NAT devices, or VPN connections, and enhancing security by keeping traffic within the AWS network.

10. AWS Network Costs: Optimizing network costs by monitoring and adjusting resources, such as using proper instance sizes, leveraging reserved instances for predictable workloads, and implementing data transfer cost optimization techniques (e.g., using S3 Transfer Acceleration, CloudFront, or Direct Connect) can significantly reduce overall AWS spend.