DVSwitch issue- Observed IP range

[akash1980]

Guys, we have issue with Dvswitch/ networking. Appreciate your help.

-  Our network engineer says he assigned multiple VLANS to our blade servers but in observed range I can see only one VLAN, I obviously I think something wrong from network side. Can you please confirm if I am right?

- Next issue, after creating dvswitch, by default all pnics are under unused uplinks, seems something wrong here but option is grayedout to move up and down. What confused me even though all vmnics are under unused uplinks, network on one VLAN which is in observed ip range works fine with dvswitch. I have configured different port groups to use the above said VLAN, they can communicate with each other and physical servers. May be it’s because all servers from where I am trying to connect to target are same subnet????

[kjb007]

The observed IP range is not coming from the network switch, per se.  It's coming from the vSwitch has seen on the wire.  This range is picked up by the traffic seen on the wire by that physical nic.  It gives you an idea of what's on the wire, but is not 100% of what is configured at the port level on the physical switch.

-KjB

[nilesh56]

Hi akash

Observed IP range is generated based on the incoming broadcast packets it detects over physical nics.

http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=100674...

It would be helpful to comment over your next problem if you attach a snapshot for one of ur host > networking > vSwitch and dvswitch

[vGuy]

As mentioned above, the observed IP range as its name suggests only reports the IP ranges observed on the vSwitch. In many cases, this can be incomplete, therefore you still need to work with the n/w team to get the list of VLANs trunked on the port.

With dvSwitch the load balancing policies are set on the individual portgroup. The association of dvuplinks to vmnics is to be done at the individual hosts settings. Are you trying to set the teaming via Portgroup settings? Is it possible to get a screenshot?

[rickardnobel]

akash1980 wrote:

-  Our network engineer says he assigned multiple VLANS to our blade servers but in observed range I can see only one VLAN, I obviously I think something wrong from network side.

As several others has noted above the Observed IP range is not 100% accurate, but you should be able to pick up broadcast frames from all VLANs / IP subnet. If you only see IP addresses from one specific network then it is likely that the others are not "trunked" (if Cisco) / "tagged" correctly.

[akash1980]

Thanks guys. I have managed to configure DVSwitch successfully with all required VLANS. But issue what I found is I couldn’t use VLAN trunking  to present multiple VLANS to a dvport group. I have configured to use a single VLAN per port group.

Response to my issues,

• -          You are correct, observed IP range is not 100% correct.
  
  
• -          My concern regarding showing all vmnics as unused at DVswitch level (top) is by design. We need to configure vmnics teaming/ load balancing at port group level.
  
  

[vGuy]

akash1980 wrote:

Thanks guys. I have managed to configure DVSwitch successfully with all required VLANS. But issue what I found is I couldn’t use VLAN trunking  to present multiple VLANS to a dvport group. I have configured to use a single VLAN per port group.

That's correct. A port group corresponds to a single VLAN ID. You cannot have multiple VLANs assigned to the same Port group, however you can have multiple Port Groups assigned with the same VLAN ID (if required).

[akash1980]

vguy,

This is something changed with vSphere.

In vSphere, there's a new networking feature which can be configured on the distributed virtual switch (or DVS). In VI3 it is only possible to add one VLAN to a specific port group in the vSwitch. in the DVS, you can add a range of VLANs to a single port group. The feature is called VLAN trunking and it can be configured when you add a new port group. There you have the option to define a VLAN type, which can be one of the following: None, VLAN, VLAN trunking, and Private VLAN. But this can only be done on the DVS, not on a regular vSwitch. See screendumps below (both from vSphere environment)

refer: http://www.vi-tips.com/2009/07/vlan-trunking-grouping-in-distributed.html

[vGuy]

Good point, Aakash. But take note that this particular option is used for VGT (virtual guest tagging).

It basically means the VLANs are tagged/stripped within the Guest OS (using a trunking driver) rather than at the port group layer.

Any reason you would want to opt for VGT instead of the default VST. Although it's a nice feature, I do not really see a use case for it as it brings unneeded complexity in the environment?

[kjb007]

You could do this before as well pre dvSwitch using VLAN 4095.  That tells ESX that you want the VM to handle the VLAN tagging.  With dvSwitches,  you get to specify your range, and effectively prune the allowed VLANs on that "trunk" you present to the vm.

-KjB