An environment has a dual-stack infrastructure in an active-active configuration in two separate data centers.

A dual-stack infrastructure is a network that supports both IPv4 and IPv6 protocols. An active-active configuration is a high-availability cluster that distributes workloads across two or more nodes that are running the same service simultaneously. Replication between the two sites means that data is copied from one site to another to ensure consistency and redundancy. Data synchronization is the process of ensuring that data is identical across multiple locations. Therefore, data synchronization in real time means that data is replicated as soon as it changes on either site, without any delay or lag. References: Active-Active vs. Active-Passive High-Availability Clustering, Dual-stack IPv6 architectures for AWS and hybrid networks – Part 2, Understanding Dual Stacking of IPv4 and IPv6 Unicast Addresses