Best Transmission Rates for EC2 Instance

Answer - B and D.

Ethernet frames can come in different formats, and the most common format is the standard Ethernet v2 frame format.

It supports 1500 MTU, which is the largest Ethernet packet size supported over most of the Internet.

Most Instance types also support an MTU of 9001 which can be used for internal VPC communication.

For more information on Network MTU settings, please visit the below URL:

To achieve the best transmission rates for an EC2 Instance, without any packet fragmentation, both inside and outside of the VPC, we need to consider the Maximum Transmission Unit (MTU) size of the packets being transmitted.

MTU is the largest packet size that can be transmitted over a network without fragmentation. When a packet exceeds the MTU, it gets fragmented into smaller packets, which affects network performance.

Now let's discuss each of the given options:

A. Configure an ENI for the instance for both internal and external traffic: This option does not address the MTU size of packets and hence does not help fulfil the requirement.

B. Configure two ENIs for the instance, one for internal traffic and the other for external traffic: This option might help in achieving the requirement. We can configure each ENI with a different MTU size to optimize packet transmission based on the destination network. However, this option may not be cost-effective as it requires two ENIs per instance.

C. Configure the single ENI for an MTU transmission rate of 9001: This option might help fulfil the requirement. However, it is important to note that the MTU size of the packets also depends on the network configuration of the VPC and the external networks. So, if the VPC and the external networks have an MTU size less than 9001, it may not provide any benefit.

D. Configure the external ENI with an MTU of 1500 and the internal ENI with an MTU of 9001: This option might be the best approach to achieve the requirement. It takes into account the fact that the external networks usually have an MTU size of 1500, while the internal network can have a higher MTU size. Hence, this configuration will allow packets to be transmitted optimally without fragmentation, both inside and outside the VPC.

In conclusion, options B and D might help fulfil the requirement, but option D is the most optimal approach. However, it is important to consider the network configuration of the VPC and external networks before deciding on the MTU size configuration.