EMC Data Domain deduplication storage systems optimize storage efficiency through the use of deduplication and compression of data at rest. When the deduplicated and compressed data is replicated using Data Domain, it is a common belief that WAN optimization is not required because a smaller amount of data is being sent across the WAN. However, in addition to limited bandwidth, at least two factors can affect the ability for replication to meet customer RPOs over a Wide Area Network (WAN): replication distance (latency) and quality of the WAN itself (packet loss and out of order packets). By solving many of the underlying network problems that plague EMC Data Domain and Silver Peak Integration Guide 5 replicating over distance, Silver Peak VXOA, when combined with EMC Data Domain Replicator, enables customers to move more data, over a longer distance, and in less time. In this paper we will describe the benefits that Silver Peak’s Virtual Acceleration Open Architecture, VXOA, provides for the Data Domain system; provide deployment and configuration examples; detail best practices; and illustrate expected performance improvements based on a customer deployment.