Architecting a Hybrid Messaging Strategy with Microsoft Exchange 2013 : Application Architectural Overview : 6.1 Mailbox Servers and Database Distribution : 6.1.3 DAG Replication Requirements
   
6.1.3 DAG Replication Requirements
All DAG-enabled mailbox server virtual machines require a minimum of two network connections. One is required for MAPI traffic and the other for replication traffic (seeding). To provide timely data replication, it is important that there be less than 50 ms link latency between the on-premises data center and the VMware Cloud Provider’s site. The log shipping network compression feature must also be enabled for each DAG to reduce the size of network packets. For more information about enabling log shipping network compression, refer to Microsoft Exchange product documentation.