Surveillance VLAN: Dahua, HikVision, etc Have Many OUIs

[rfj]

I have a new switch that has a "Surveillance VLAN". It is based on OUIs (Organizationally Unique Identifier), i.e. the first three bytes of the MAC. When I looked at the MACs of all my cams it appeared all of them have different OUIs and I only have two brands plus one Amcrest. So I used the following tool to look up the manufacturer based on all those OUIs Wireshark · OUI Lookup Tool The tool actually showed the right manufacturers. So does Dahua, HikVision, etc have that many OUIs? If so, how useful is a "Surveillance VLAN" when most of the cams have different OUIs anyways? I might as well just filter on the full MAC.