VMware Hybrid Cloud Extension delivers secure and seamless app mobility and infrastructure hybridity across vSphere 5.0+ versions, on-premises and in the cloud.

HCX offers bi-directional application landscape mobility and data center extension capabilities between any vSphere version. HCX includes vMotion, Bulk Migration, High Throughput Network Extension, WAN optimization, Traffic Engineering, Load Balancing, Automated VPN with Strong Encryption (Suite B) and secured data center interconnectivity.

This blog post will not delve into all the HCX features but will instead on the standard use cases:

  • HCX provides the ability to extend networks and through its incorporated WAN Optimization engine, enables customers to vMotion workloads over Internet (unlike NSX L2VPN, which requires a Direct Connect).
  • HCX has retro-compatibility with vSphere 5.0 versions. This is especially relevant and useful in the DC evacuation use case as customers do not need to upgrade their VMware estate to connect to VMware Cloud on AWS and they can simply ‘lift and shift’ applications and migrate hundreds of VMs out of their DC to the Cloud (and back if necessary) in a matter of days, if not hours.

Let’s look deeper into how HCX works.

HCX Details

During the initial installation, a single appliance is installed at the source, which is the HCX Manager.

It will install one or more of the following appliances as required by your use:

  • Hybrid Interconnect Appliance: This gateway provides a secure hybrid interconnect to the remote site with intelligent routing to avoid networking “middle mile” problems.
  • WAN Optimization Appliance: This appliance improves performance by utilizing WAN optimization techniques such as data de-duplication and line conditioning.
  • Network Extension Service Appliance: This appliance extends L2 networks to the remote site. This enables moving VMs to the cloud without IP and MAC address changes.

A HCX Manager on the Cloud side and the 3 Appliances (Hybrid Interconnect, WAN Optimization and Network Extension Service) will also be installed on the Cloud Side, once HCX is Activated on the “VMware Cloud on AWS” side.

The following detailed network diagram explains the overall architecture and network flows behind the HCX engine.

HCX Network Ports

The HCX Network Extension provides a High-Performance (4–6Gbps) service you can extend the Virtual Machine networks to VMware Cloud on AWS.

Virtual Machines that are migrated or created on the extended segment at the remote site are Layer 2 next to virtual machines placed on the origin network.

With Network Extension , the default gateway for the extended network only exists at the origin site. Traffic from Virtual Machines (on remote extended networks) that must be routed returns to the origin site gateway.  

Note    This applies also to a network stretch with a NSX L2VPN.

No local egress with L2VPN

Using HCX Network Extension with HCX Migration you can retain the IP and MAC addresses of the Virtual Machine as you migrate it to the Cloud.

HCX lets you extend VLAN networks (from VMware’s vSphere Distributed Switch), from VXLANs (assuming NSX is configured at the source site) and Cisco Nexus 1000v networks.

Do not extend the management VLAN under any circumstance.

Once the secure tunnel has been established between the HCX Source and Destination sites, the migration can start.

The Network Extension is not required for HCX. Without it, you can still leverage HCX (and its benefits such as retrocompatibility to vSphere 5.0 and its WAN Optimization engine) to migrate workloads if maintaining the IP address is not a strict requirement.

The following picture describes the overall architecture of HCX:

Finally, this is what the end product looks like – a live vMotion of a VM from our DC in Austin, Texas to VMware Cloud on AWS in North Virginia. Done in 4 minutes (the video below was edited).

Live vMotion across America

14 thoughts on “HCX

  1. Hi ! I have a question related to HCX migration

    I have a site under ESXi 6.5 and I would like to create a new site for disaster recovery purposes and take this opportunity to run VMware Cloud Foundation.

    I know that the migration is mandatory but can I continue to using the first site under ESXi 6.5 considered legacy afterwards ?

    I don’t want to lose it.

    The final plan is to build a private cloud with two sites :

    – the legacy site under ESXi 6.5
    – the new site under VMware Cloud Foundation


    1. From a technical perspective, you’ll be fine but you might have an issue from a support perspective. I don’t work at VMware anymore though – you should talk to your VMware sales team about supportability going forward. Good luck with your migration!


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