Objective 4.4SAA-C03

4.4 Design cost-optimized network architectures.

Objective 4.4 sits in Design Cost-Optimized Architectures, which carries 20% of the Solutions Architect Associate exam. The questions below are original, written from the official objective title above, and each explanation cites the Amazon Web Services (AWS) page it rests on.

Objective title verbatim from the official objectives. Amazon Web Services (AWS) exam page

A worked example

Shown solved, with the whole explanation open: this is what every question here carries.

4-4Design Cost-Optimized ArchitecturesModerate

Instances in private subnets pull terabytes from S3 every month through a NAT gateway, and the data processing charge dominates the network bill. What removes it?

A gateway VPC endpoint for S3Correct · your answerCorrect. Traffic leaves the metered path and the endpoint itself is free.
An interface VPC endpoint for S3An interface endpoint also keeps traffic private, but it bills per hour and per gigabyte, so a large volume still costs.
A second NAT gateway in each zoneMore NAT gateways multiply the hourly charge and process the same volume of data as before.
An internet gateway route addedRouting private subnets at an internet gateway makes them public, which fails the isolation the design depends on.

Correct.

Concept

Traffic to an AWS service that never needed to leave the network is being charged as though it did. Routing it through an endpoint inside the VPC takes the metered device out of the path entirely rather than making that device cheaper.

Why A

A gateway endpoint gives private subnets connectivity to S3 without an internet gateway or a NAT device, and AWS charges nothing additional for using one. The terabytes stop crossing the NAT gateway, so its per-gigabyte processing charge disappears.

Source

#vpc-endpoints#s3#data-transfer-cost

Now you: objective 4.4 questions

No account needed. The explanation opens when you answer.

Sample question 1 of 3

4-4Design Cost-Optimized ArchitecturesHard

To save money a team runs one NAT gateway and routes private subnets in all three Availability Zones through it. What does that choice cost them?

Sample question 2 of 3

4-4Design Cost-Optimized ArchitecturesModerate

Two VPCs owned by different accounts sit in the same Availability Zone and exchange large volumes over a peering connection. Finance asks what that traffic costs.

Sample question 3 of 3

4-4Design Cost-Optimized ArchitecturesHard

Two Regions replicate data between VPCs over public endpoints today. The team wants private addressing, encryption in transit and a lower bill. What do they build?

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Read the sources

These are the official pages the questions above cite. Reading them is studying the objective from the primary source, which is what the explanations point you toward anyway.

More objectives in Design Cost-Optimized Architectures