ANS-C01 · Question #20
A company operates its IT services through a multi-site hybrid infrastructure. The company deploys resources on AWS in the us-east-1 Region and in the eu-west-2 Region. The company also deploys…
The correct answer is C. Add the aggregate IP prefix for the other Region and the local VPC CIDR blocks to the list of E. Remove all the VPC CIDR prefixes from the list of subnets advertised through the local Direct. If the private WAN failed, the network engineer would swing the traffic to the other region through the local Direct Connect and the Transit Gateways. That is the requirement. The solution is that the local DC has 2 kinds of route to the other region VPCs. One is the existing…
Question
A company operates its IT services through a multi-site hybrid infrastructure. The company deploys resources on AWS in the us-east-1 Region and in the eu-west-2 Region. The company also deploys resources in its own data centers that are located in the United States (US) and in the United Kingdom (UK). In both AWS Regions, the company uses a transit gateway to connect 15 VPCs to each other. The company has created a transit gateway peering connection between the two transit gateways. The VPC CIDR blocks do not overlap with each other or with IP addresses used within the data centers. The VPC CIDR prefixes can also be aggregated either on a Regional level or for the company's entire AWS environment. The data centers are connected to each other by a private WAN connection. IP routing information is exchanged dynamically through Interior BGP (iBGP) sessions. The data centers maintain connectivity to AWS through one AWS Direct Connect connection in the US and one Direct Connect connection in the UK. Each Direct Connect connection is terminated on a Direct Connect gateway and is associated with a local transit gateway through a transit VIF. Traffic follows the shortest geographical path from source to destination. For example, packets from the UK data center that are targeted to resources in eu-west-2 travel across the local Direct Connect connection. In cases of cross-Region data transfers, such as from the UK data center to VPCs in us-east-1, the private WAN connection must be used to minimize costs on AWS. A network engineer has configured each transit gateway association on the Direct Connect gateway to advertise VPC-specific CIDR IP prefixes only from the local Region. The routes toward the other Region must be learned through BGP from the routers in the other data center in the original, non-aggregated form. The company recently experienced a problem with cross-Region data transfers because of issues with its private WAN connection. The network engineer needs to modify the routing setup to prevent similar interruptions in the future. The solution cannot modify the original traffic routing goal when the network is operating normally. Which modifications will meet these requirements? (Choose two.)
Options
- ARemove all the VPC CIDR prefixes from the list of subnets advertised through the local Direct
- BAdd the CIDR prefixes from the other Region VPCs and the local VPC CIDR blocks to the list of
- CAdd the aggregate IP prefix for the other Region and the local VPC CIDR blocks to the list of
- DAdd the aggregate IP prefix for the company's entire AWS environment and the local VPC CIDR
- ERemove all the VPC CIDR prefixes from the list of subnets advertised through the local Direct
How the community answered
(31 responses)- A6% (2)
- B26% (8)
- C58% (18)
- D10% (3)
Explanation
If the private WAN failed, the network engineer would swing the traffic to the other region through the local Direct Connect and the Transit Gateways. That is the requirement. The solution is that the local DC has 2 kinds of route to the other region VPCs. One is the existing CIDR-based routes via the private WAN, another is the advertised aggregated routes from the local Direct Connect connection. CIDR-based routes are prior to the aggregated routes advertised from Direct Connect connection due to the longest prefix match routing algorithm.
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