You have a set of EC2 instances in a VPC located at US-East-1. You need to have optimal network performance on these instances. These instances will talk to instances in another VPC located at US-East-2 via VPC Peering. Which of the following should be carried out to ensure maximum network performance? Choose 2 answers from the options given below.

Answer options:

A.Enable Enhanced Networking on the Instances.
B.Set the MTU on the Instances to 9001.
C.Ensure the operating system supports Enhanced networking.
D.Create 2 availability zones for the instances in the primary VPC and place them in a placement group.

Answer – A and C
Option B is incorrect since the MTU of 9001 will not work in VPC peering. The maximum that is allowable in VPC peering is 1500.
For placement groups to work, the instances must be placed in the same availability zone.
The AWS Documentation mentions the following.
Enhanced networking uses single root I/O virtualization (SR-IOV) to provide high-performance networking capabilities on supported instance types. SR-IOV is a method of device virtualization that provides higher I/O performance and lower CPU utilization when compared to traditional virtualized network interfaces. Enhanced networking provides higher bandwidth, higher packet per second (PPS) performance, and consistently lower inter-instance latencies.
For more information on Enhanced Networking, please refer to the below URL
https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/enhanced-networking.html
When we implement intra-region VPC peering jumbo frames provide MTU of 9001 provided that both the instances do support Jumbo frames.
When we implement inter-region VPC Peering, the maximum MTU that we receive with Jumbo frames is 1500.