CISCO 350 multiple uplink between two switch

[fabiodna]

Hi 

I have a network with some CISCO 350 Switch.

I define 3 VLAN:

VLAN 1 Default, VLAN 3 VOIP and VLAN 4 VIDEO

Every switch is connected to another with 3 uplink, and every uplink port is configured as trunk and have one default VLAN associated.

I would like each VLAN to use only its own trunk port correctly.

So I would:

port 21 send/receive VLAN 1 traffic

port 23 send/receive VLAN 3 traffic

port 24 send/receive VLAN 4 traffic 

But now all traffic use the same trunk port, one of the three.

See attachment for my port configuration.

Thanks

[Karsten Iwen]

Is there a particular reason that you want to do it that way? I would consider that an operational nightmare. Not only because your Per-VLAN-STP needs to be configured appropriate.

The "normal" and likely better way is to build a LAG between these switches. STP sees one virtual Link for all VLANs and if you add a forth link you likely have a quite balanced traffic distribution on all links.

[Kasun Bandara]

your requirement is not clear. normally if you configure access port with access VLAN associated, traffic will tag to relevant vlan when traffic taking to inside of switch. then it looks for same VLAN access ports or Trunks which allowed that vlan and passing traffic via that according MAC table. if you need only to transfer specific VLAN in specific port, you can tag that and allow only that vlan through selected trunk port. so when switch sending traffic it will sends only allowed vlans's traffic via trunk as tagged. 

 as  @Karsten Iwen said, you can make a LAG between switches and allow VLANs on that LAG port. then you ll have more bandwidth between switches. 

[fabiodna]

We want to separate the VIDEO traffic from all the others, because it is very intense.
For this reason we wanted to split the traffic, using separate VLANs and connections.
As you say it may not be the correct solution.

I tried setting a specific vlan on the specific trunk port, but when I set it on the first ge21 port, all traffic from the other VLANs stopped.

Is it due to the fact that I have to do it on both switches for the corresponding ports?

[Karsten Iwen · Accepted solution]

As already said, this is likely Spanning-Tree blocking the other links. You need Per-VLAN-Spanning-Tree or MSTP with multiple instances so that each VLAN has a non-blocking path between the switches. Good luck!