Azure VMware Solution packages cloud infrastructure with VMware vSphere, HCX Advanced, NSX-T, and vSAN technology. Customers can upgrade the HCX version to HCX Enterprise Edition and gain access to advanced services like Replication Assisted vMotion and Mobility Optimized Networking. These additional HCX features greatly simplify and optimize bulk live migrations from on-premises to Azure VMware Solution. With this announcement Microsoft is also offering Azure VMware Solution customers a promotion to upgrade to HCX Enterprise free of charge, the offer will run for a minimum of 12 months. See pricing details.
Included with the latest version of HCX Enterprise Edition (4.2 release notes), is Mobility Optimized Networking this enables customers to extend networks from NSX-T to ensure traffic between the source (data center) and destination (private cloud) is optimally routed and remains symmetric. In the absence of Mobility Optimized Networking, traffic on extended networks will be forwarded back over to the source router thereby causing inefficiencies and latency issues.
Additionally, the latest release of VMware HCX version 4.2 includes support for HCX over VPN and SD WAN, and is supported with Azure VMware Solution. For more information on the HCX network underlay see here Network Underlay Minimum Requirements (vmware.com)
For more details on how to install the HCX connector for Azure VMware Solution, see MS docs pages. If you would like more information on Mobility Optimized Networking, please refer to this VMware article.