Multiple VLANS on 1 switchport

Answered Question
May 1st, 2012

Hello,

I have a a hardware server running a VM hosting virtual servers which are all on different VLANs. My challenge now is to configure the switchport that the server is connected to, to see all the VLANs needed by this VM. The VM has an IP that is used for managing the server VMs which is on a different VLAN also.

My switch is a 2960 switch and it is presently trunked from the core switch.

Any suggestions please?!

Regards,

Femi

I have this problem too.
0 votes
Correct Answer by ryan.wolfe about 1 year 11 months ago

Just to caveat off of that, as far as I understand with VMware virtual machines, the virtual machines have something like a "virtual switch" built into them to do basic layer 2 functions. Like you said, each machine is on a different VLAN. So, in order for them to be able to tag there traffic specific for each VM, they must do it on there own because a switch can only tag data traffic unanimously on an interface. Since multiple VLANs coming into an access port will be ignored, you have to put the port into trunk mode.

I got that info from a VMware engineer on a tech conference whenever I was asking about virtualizing network devices.. So, it seems trustworthy.

HTH,

Ryan

Sent from Cisco Technical Support iPad App

Correct Answer by John Blakley about 1 year 11 months ago

You have to trunk the port that the VMWare server is connected to. I'm not a VMWare guy by any means, but I manage our switches at work. We have VMs that run off of trunk ports and the server team adds vlans to the trunk port. If you don't know how to do that piece, you may need to get in touch with VMWare to see if they can help you.

HTH,

John

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Correct Answer
John Blakley Tue, 05/01/2012 - 17:53

You have to trunk the port that the VMWare server is connected to. I'm not a VMWare guy by any means, but I manage our switches at work. We have VMs that run off of trunk ports and the server team adds vlans to the trunk port. If you don't know how to do that piece, you may need to get in touch with VMWare to see if they can help you.

HTH,

John

Correct Answer
ryan.wolfe Tue, 05/01/2012 - 18:16

Just to caveat off of that, as far as I understand with VMware virtual machines, the virtual machines have something like a "virtual switch" built into them to do basic layer 2 functions. Like you said, each machine is on a different VLAN. So, in order for them to be able to tag there traffic specific for each VM, they must do it on there own because a switch can only tag data traffic unanimously on an interface. Since multiple VLANs coming into an access port will be ignored, you have to put the port into trunk mode.

I got that info from a VMware engineer on a tech conference whenever I was asking about virtualizing network devices.. So, it seems trustworthy.

HTH,

Ryan

Sent from Cisco Technical Support iPad App

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Posted May 1, 2012 at 5:36 PM
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Tags: vlan, vlans
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Categories: Switches
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