Exam 300-610 topic 1 question 83 discussion

The key here is that the question refers to data center network and shared services. Within a router you would be able to use for instance BGP or OSPF to perform the route leaking, but VXLAN is the answer for the data center since it supports the feature natively.

VXLAN is correct, there was no VRF isolation requirement. The requirement was a shared service that had DNS that should be reachable to everything in the network.

VXLAN is not an appropriate solution, as you'll allow the traffic between all VRF as there is no control access via VXLAN, so there is no restriction among all VRFs as one routing table.

Route replication is supported for static, EIGRP, and OSPF routes. It is not possible to replicate routes to and from BGP, but that is not an issue because the BGP import and export method of copying routes between VRFs is available in a virtual network. https://www.cisco.com/en/US/docs/ios-xml/ios/evn/configuration/xe-3sg/evn-shared-svcs.html