Exam AWS Certified Advanced Networking - Specialty ANS-C01 topic 1 question 95 discussion

it's C Note: With an Active/Active configuration, the customer gateway must have Asymmetric routing activated on the virtual tunnel interfaces. https://repost.aws/knowledge-center/vpn-configure-tunnel-preference

only C is correct!

C - The tunnel needs Asymmetric Routing Static VPNs created between a customer gateway and either a virtual private gateway or a transit gateway In this scenario, the virtual private gateway or transit gateway sends traffic from AWS to the on-premises network on a single VPN tunnel. This tunnel is randomly chosen by AWS and is referred to as the preferred tunnel. If the AWS VPN connection (static routing type) has an Active/Active configuration (both tunnels are UP), then you can't configure AWS to prefer a specific tunnel to send traffic. For example, tunnel A was randomly chosen by AWS as the preferred VPN tunnel for sending traffic from AWS to the on-premises network. If tunnel A goes down, then traffic from AWS automatically fails over to tunnel B. Note: With an Active/Active configuration, the customer gateway must have Asymmetric routing activated on the virtual tunnel interfaces.

In an Active/Active configuration with ECMP routing, where both tunnels are utilized simultaneously, enabling asymmetric routing on the virtual tunnel interfaces of the customer gateway is indeed necessary to accommodate the bidirectional flow of traffic over the two tunnels.

Asymmetric Routing has to be allowed on the customer gateway...

Configure the virtual tunnel interfaces on the customer gateway to allow asymmetric routing. This will: Allow return traffic to flow over different tunnel than initial traffic Maintain full bandwidth of both tunnels with active/active VPN Not require modifying BGP settings or preferring a tunnel The other options do not fully meet the needs: A – AS PATH prepending impacts overall BGP behavior B – Specifying a primary tunnel reduces equal bandwidth use D – Static routing disables ECMP and load balancing

I think that it's correct answer is C according to SPOTO products.

C is the right answer.

Every other option except option C will reduce overall bandwidth.

Must be C, The static route will prefer specific link so without reducing BW, we can enable asymmetric routing to utilize both links.

Should be D.