So it works :-) but let's take it one step further and add-in some NSX-T 3.0 magic. Now I must be able to ping from the vPC to the yVM. That's why you see 1 which is the default (unused) VLAN on this trunk. So if you put 10 in here it doesn't work. The VLAN that's configured on the dot1q (IEEE 802.1Q) port is the VLAN that's NOT forwarded to the cloud component. The switch is configured with a trunk (dot1q) downlink to the cloud component, the uplink is configured as a VLAN access port with ID 10. The switch is connected to a virtual PC with IP address 172.16.10.21. On the other side, The cloud component is connected to the virtual network adaptor of my GNS3-VM and attached it to a GNS3 ethernet switch "Switch1". The IP address of this yVM is 172.16.10.20. I've also deployed a yVM (An ultra-small VM with VM tools) and attached it to a port group configured with VLAN 10. So Promiscuous mode, MAC address changes, and Forged transmits must be enabled. Make sure that the security settings on this port group are all enabled. To load it permanently so it survives reloads of the VM: Taken from: Enabling 802.1q on the GNS3 VM
CONNECT GNS3 TO PHYSICAL NETWORK INSTALL
This adaptor must be able to forward tagged traffic from the cloud component so we have to install the Ubuntu VLAN kernel module. So I have One network adaptor that's attached to a port group configured in trunk mode (Edge-Uplinks). There's one other thing you need to do and that's removing one network adaptor. I also changed some settings of the GNS3-VM and configured an additional vCPU and a bit more memory. The client interface is configured with the fully qualified domain name of the GNS3-VM and port 80 instead of the default 3080. The user-interface of GNS3 is a separate client that runs on your workstation but the network virtualization is done in the GNS3-VM virtual machine. The GNS3-VM can run as a virtual machine hosted on ESXi. This simulation is done by hosting the original binaries on a network virtualization platform.
GNS3 is a great free product that's able to simulate routers and switches.
CONNECT GNS3 TO PHYSICAL NETWORK HOW TO
This article describes how to simulate VLAN ID's in your home lab without the need for a physical switch and how to create a bridge between a VLAN in GNS3 and a segment in NSX-T.