Inter VLAN logic

I've been looking around for posts about VLAN configuration but without finding something that seems an answer to my questions. I'm on a quest to configure my network to control bandwidth through SQM for 4 main types of Internet connections.: VoIP, IOT, media/gaming and PC/phones/laptop.

So far, I managed to create 2 VLAN, for IOT and VoIP. Thing is, they are both directly connected to the router so configuration is pretty straightforward.

Right now, I'm really into "trying to understand" the logic of Inter VLAN rather than configuring it. My issue is to understand Inter VLAN, as the management of the 2 other groups has to happen through 4 "switches 2 running Openwrt, one Cisco and one Netgear. As a whole, 3 switches are in three different rooms where both types of devices are connected (media gaming and PCs). The 4th switch connects everything together and links to the router.

  1. my first question, how do I configure the ports of the switches in the room, considering it's a mix and match of both VLAN (for 3-4 ports) and one is the link to the rest of the network, and should be a trunk port if I get it right

  2. how should be configured the central switch if all three zones connected to it would send data for a mix of two VLAN?

I guess we could start with this. I am a bit mixed up between what tagged and untagged means, and when to use one or the other on the port, the CPU or the outgoing port to the other switch.


On each router or switch, the ports that connect one switch with another can mix several VLANs, but all traffic must be tagged, with a different ID for each VLAN.

On the ports where other devices are connected, traffic must belong to a single VLAN, and must be untagged.

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In the OpenWrt switch configuration, the CPU port is also tagged for all VLANs, assuming your OpenWrt router has a built-in switch chip.

The OpenWrt network interfaces are configured with a physical interface ethX.Y, where ethX represents the connection to the built-in switch, and Y is the VLAN ID.

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Ok this seems to work fine.

I guess I am only unsure as to what means tag and untag vs when you set it. I applied the recipe on all OpwnWRT devices and the Netgear switch and it worked fine. Within a few minutes, I was even able to isolate my work PC in order to guarantee some bandwidth while the kids were gaming and streaming videos.

But, when try the same on the old Cisco router, it does not seem to work. I'll post something somwhere else I guess. Thanks.

something like this ( quick copy paste may not be correct / compatible with your IOS version ) the principle is pretty much the same tho'... just set the mode and use '?' to finish the rest of the commands.

sample cisco cmds
conf t
interface GigabitEthernet1
 description access-client-vlan10
 spanning-tree disable 
 switchport mode access
 switchport access vlan 10
interface GigabitEthernet2
 description trunk-to-openwrt-on-lan4
 switchport mode trunk 
 switchport trunk allowed vlan add 10 tagged
 switchport trunk allowed vlan add 20 tagged
 switchport trunk native vlan none

or a more complex ( mixed-mode ) trunk ( if mode general supported )

 switchport mode general 
 switchport general allowed vlan add 90 tagged 
 switchport general allowed vlan add 5 untagged 
 switchport general forbidden vlan add 1 
 switchport general pvid 5

I recognize Cisco verbiage, but I am not at this level of knowledge and I don't think I can setup the Cisco router that way. Its an old RVS4000 and the only thing I have available is a GUI like so.

Basically, one menu allows me to create the VLAN ( 1 is used for everything, 30 for entertainment and 40 for work and PCs).

The other one allow me to define what I do with the Ports (tag, untag or trunk). Port 1 is linking to the rest of the network, 2 and 3 should be 30 and 4, 40.

And the other to set the relations between the ports and the VLAN. What I can see:

  1. If I set a port to trunk or untag, it must be set to a PVID
  2. If I set a port to tag, I can tag as many VLAN I can.

So according to the above, when I try tag 1 and tag 30 on port 1, untag 30 on port 2 and port 3 it does not work.

If I try trunk on port 1 PVID 1 and untag 30 on port 2 and 3 it does not work either.


Looks like need to see one of the 'port settings' tabs, for the trunk port.

The picture apparently did not follow...

Solved, after trying several time the automatic configuration of the smart Tv, I decided to feed it all the information manually, IP address, gateway and DNS. It worked like a charm. I guess the automatic configuration was looking for 192.168
X.Y type of address.

I used the same approach for the Cisco router as for the openwrt one BTW.

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