Hi,

A virtual network (VLAN) operates at layer 2 of the OSI model. By default, Layer 2 devices forward or filter frames by MAC address. Therefore, for a source device to communicate with a layer 2 destination device, MAC learning is required.

@Mysterious.color Hi,
As in my opinion, switch learns MAC address based on interfaces, rather than VLANs,while the interfaces are bind to different VLANs. Based on these information, the CAM entries generated on the switch.
Switch forwards the traffic based the CAM entries.

In addition, VLAN seperates the broadcast domain, and limit the broadcast traffic spreading in the same VLAN, which would help to reduce the useless traffic on the switch, and the consumption of the hardward, bandwidth

Do you mean that the same mac is learned by different VLANs on different ports? That's MAC address flapping, caused by the network loop.

On S series switches (except S1700), MAC addresses are learned based on MAC addresses+VLANs. If multiple VLANs receive packets with the same MAC address, these VLANs will learn the same MAC address.

thank you all for your answer
it was helpful