Multiple AWS DX Connections from 2 different locations are commissioned by a government organization to access web applications deployed in AWS cloud infrastructure. Users are complaining of session interruption while accessing a legacy software deployed on EC2 instance in AWS VPC. Further analysis shows an asymmetric traffic flow between users in the government offices & servers over both AWS DX links. To avoid varied latency from both AWS DX links, the client wants a primary AWS DX connection as a preferred path to AWS & a secondary AWS DX connection should be a backup in case of primary link failure. Which of the following additional configuration changes will meet this requirement?

Answer options:

A.Add Local Preference BGP Community Tag 7224:7200 on the primary Link & Local Preference BGP Community Tag 7224:7200 on the secondary link.
B.Add Local Preference BGP Community Tag 7224:7100 on the primary Link & Local Preference BGP Community Tag 7224:7200 on the secondary link.
C.Add Local Preference BGP Community Tag 7224:7300 on the primary Link & Local Preference BGP Community Tag 7224:7100 on the secondary link.
D.Add Local Preference BGP Community Tag 7224:7200 on the primary Link & Local Preference BGP Community Tag 7224:7300 on the secondary link.

Correct Answer – C
Local Preference BGP Community Tag can be used to set route preferences for incoming traffic to the customer network. Supported Local Preference BGP Community Tag are as follows
1)7224:7100—Low preference
2)7224:7200—Medium preference
3)7224:7300—High preference
In the above case, to prefer incoming traffic over the primary link, the client can add high preference Tag 7224:7300 for the primary link& tag 7224:7100 for the secondary link.
Option A is incorrect as having the same tag on both primary & secondary links will load balance the traffic.
Option B is incorrect as having medium preference 7224:7200 tag on the secondary link will prefer it over the primary link.
Option D is incorrect as since the high preference tag 7224:7300 is added to the secondary link, the secondary link will be preferred.
For more information on using BGP Community Tags with AWS Direct Connect, refer to the following URL
https://docs.aws.amazon.com/directconnect/latest/UserGuide/routing-and-bgp.html