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VMware Networking Terminology

Posted on 2014-02-20
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Last Modified: 2014-02-21
When I click on ESX host , select Configuration tab then Networking, I see:
on the Top frame :
Virtual machine port group, then VMNetwork
Then Virtual machines.
What I do not understand is the VMNetwork word, why it is there? and it has on its right an icon connected to the virtual switch. What is exactly VMNetwork? they could have just the Virtual Machine Port Group and the VMs.

on the second frame:
I see VMKernel Port Then Management Network then vmk0 pointing to ESX host IP address.
I know that VMKernel is used for vmotion and storage. What I retain from these frames , is wherever there is ESX host, there is VMKernel.

Why Management Network is there ? they could have skipped it...
vmk0, to me means the interface of ESX host…is that correct ?
is there difference between vmk0 interface and Vmkernel interface ?

anyone to clear up the confusing terminology ?

Thanks
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Question by:jskfan
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Author Comment

by:jskfan
ID: 39875813
I have seen in some cases where they have 2 Vmkernel interfaces with 2 different IP address, even though there is only one physical NIC.
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by:Abhilash
Abhilash earned 307 total points
ID: 39875866
In Virtual networking there are two kinds of traffic.
One is the management traffic.
Where you will access the ESXi host, The heartbeat signals are carried out, vMotion network and IP storage.

Other is Virtual machine traffic.
This carries all the data traffic between the machines and between machines and outside world.

So VMKernel portgroup you see is the one responsible for management traffic and all the kernel related activities. If you don't have vmk0 present you will have no way to even access the ESXi host because the IP that you give in the DCUI is assigned to this. There is no way they can skip it. If they skip this then you will not have a ESXi.

And Virtual machine has to be there because its always better to have segregation between management and Virtual machine traffic. VM Network is the name of the portgroup. Virtual machine portgroup is the type of portgroup and VM Network is the name you give to identify what traffic is flowing through it. If you are the only one in your organization using that portgroup you can name it JSKFAN. The name is used for your identification.


And when there are many different VMKernel ports they are usually used for different things like FT, vMOtion and IP storage. They can also run on the actual management traffic but again to have segregation you can put them on their own VMKernel portgroup.

VM Network is a default port group name that is created when you install ESXi. If you want to know why its really used. Just go to any VM and click on Edit settings>NIC card and see the dropdown and see if you will find management portgroup. You will not. ESXi never lets you put a VM on the VMKernel portgrooup.  You should always have a Virtual machine portgroup to make a VM communicate outside.
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by:Andrew Hancock (VMware vExpert / EE MVE^2)
Andrew Hancock (VMware vExpert / EE MVE^2) earned 153 total points
ID: 39876263
for traffic to reach your Virtual Machines, a Virtual Machine Portgroup which carries virtual machine traffic only must be created, and and connected to a virtual machine.

This is network traffic which enters the physical uplinks, into the virtual switch (vSwitch), and then needs to exit, on a portgroup defined as a virtual machine portgroup, you can have more than one, and multiple using VLANs, and they require a friendly name.

VMware have just chosen VMNetwork.

But we have networks called DMZ, Production, Research, Private, VLAN 101, VLAN 102, etc which ever makes it easier to recognise which network it is.

If you want to read more on networking in VMware ESX/ESXi, then I recommend the following:-

I would also recommend reading through the Networking Sections of the following guides to gain a better understanding of Networking in VMware ESX/ESXi.

Pages 13 - 73 Discuss Networking in Detail, including trunks, VLANs, switches, and load balancing

ESXi Configuration Guide ESXi 4.1
http://www.vmware.com/pdf/vsphere4/r41/vsp_41_esxi_server_config.pdf

Virtual Networking
http://www.vmware.com/technical-resources/virtual-networking/virtual-networks.html

Virtual Networking Concepts
http://www.vmware.com/files/pdf/virtual_networking_concepts.pdf
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Assisted Solution

by:asavener
asavener earned 40 total points
ID: 39877004
VM Network is just a default port group that gets created on your vSwitch.

You can rename it if you wish.
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Author Comment

by:jskfan
ID: 39877013
vm
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LVL 119
ID: 39877031
Screenshot posted is your Virtual Machine Network Portgroup - VMNetwork

which you can rename!
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Author Comment

by:jskfan
ID: 39877065
I see :

VM Network has an icon on the right side of it (blue circle icon on Vswitch)
Vsphere Replication Appliance (this is a Virtual machine appliance) has an icon on the right side of it (green arrow icon on vswitch)
Management Network has an icon on the right side of it (blue circle icon on Vswitch)

** For instance the virtual machine (VRA), Does its own traffic goes through its own virtual interface(green arrow icon) or goes through VM Network interface (blue circle icon) ?
in other words, what kind of communication goes between the 2 interfaces?


** Apparently ESX host , Vmotion traffic goes through Management Network interface(blue circle icon).

is Management Traffic isolated from VM Network traffic, I believe there should be some traffic that goes between them, for instance when ESX host provides CPU/RAM to VMs…if so what's the name of this traffic?
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Abhilash earned 307 total points
ID: 39877094
The blue circle that you see is the symbol for a portgroup.
The green arrow on the VRA VM is not related to networking, thats how a powered on virtual machine looks.
The Green dot you see next to the VRA VM is the port that its connected on the vSwitch.

The traffic of the VRA appliance goes through the green dot that is there. But it also is associated with the blue circle as its the main symbol for the portgroup.

Yes the management traffic is isolated from VM network.
And yes there is also some traffic that's going in between them like the VM sends heartbeat to the host telling its alive and also MKS traffic. The host redirects the console traffic to VM Network traffic. Its a very thin line between the segregation of traffic between the portgroups. You do not need to learn about it because the Kernel knows how to handle it and its all internally done.

Do not get confused by the symbols. They are just representations. Learn how the networking works. That's more important.
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Author Closing Comment

by:jskfan
ID: 39877212
Thank you Guys!
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