Overlay Transport Virtualization (OTV) is a MAC-in-IP method that extends Layer 2 connectivity across a transport network infrastructure

To utilize overlay network internal VM communication with an existing Edge switch, you can implement a solution like VXLAN (Virtual Extensible LAN) or NVGRE (Network Virtualization using Generic Routing Encapsulation). These technologies encapsulate Layer 2 packets within Layer 3 packets, enabling communication across Layer 3 boundaries while maintaining the logical separation of networks. By configuring the Edge switch to support VXLAN or NVGRE, you can establish communication between VMs within the overlay network, allowing them to communicate seamlessly across the existing network infrastructure without the need for significant changes to the underlying network architecture.

Configuration of overlay is not a simple steps. You should have harden knowledge of Switching, routing, trunks, and etc..

Familiarize yourself with your existing network topology, including the configuration of the Edge switch, VLANs, and IP addressing.
If VLANs are in use, ensure that the overlay network is appropriately configured to work with your VLAN settings. Make sure the VLAN tags used in the overlay network align with the VLAN configuration on the Edge switch.
On your existing Edge switch, configure the necessary VLANs to match those used in the overlay network. This ensures that the Edge switch can understand and properly handle traffic from the overlay network.

Overlay network is compose of switches that are capable of microsegmentation.

To facilitate overlay network internal VM communication with an existing Edge switch in your current network topology, you would typically need to ensure proper configuration of the overlay network and connectivity between the overlay and the physical network.

Conversely, if the virtual switch is isolated from the edge, the communication becomes more streamlined. Data packets now solely pass through the virtual switch and utilize the overlay network for direct communication with resources on other nodes. This method is more efficient, as traffic into the virtual switch primarily utilizes the overlay network and only accesses the physical network when necessary.

Within Sangfor HCI clusters, an edge-connected interface serves as the vital link to the physical network. This interface is crucial for communication between the HCI cluster and external networks. VMs within the Sangfor HCI environment are accessed from external networks through this edge-connected interface.

When the same virtual switch is shared by two VMs:
Before packets reach the other virtual machine (VM), they physically leave the edge, travel across the physical network, and then return to the edge if the virtual switch is not isolated from the edge.
Packets only transit via the virtual switch and utilize the overlay network to access resources on other nodes if the virtual switch is separated from the edge.
The latter strategy is more effective as traffic entering the virtual switch mostly makes use of the overlay network and only sometimes reaches the actual network.

Hi,
Please have a look on this post:
https://community.sangfor.com/fo ... thread&tid=4650

If a virtual switch is isolated from edge, packets only pass through the virtual switch (and through overlay network to reach resources on other nodes).