Difference between Physical and Virtual Swiches

[vcpguy]

Guys,

Can you please tell me the difference between the physical and Virtual Switches?

I do have idea about it. But, I would like to have few more information

Thanks

[khughes]

Basically a virtual switch (right now) is just a dummy switch, traffic is just passed through there is no configuration done on this switch. A physical switch (depending on what type of physical switch) allows you to make moficiation and configurations on it.

• Kyle

[Ken_Cline]

A vSwitch is software that is instantiated by the vmkernel for the express purpose of managing network traffic into and out of an ESX server.

- - It is essentially a dumb, unmanaged layer 2 switch that does not participate in spanning tree protocol negotiations.

- - You can configure a vSwitch with up to 1016 ports on it.

- - Physical NICs are connected to a vSwitch and serve as uplink ports.

- - You create port groups on a vSwitch to facilitate ease of management and also to implement 802.1Q VLAN trunking

- - There are three types of port groups:

- - - vmkernel: used for VMotion and IP-based storage

- - - Service Console: used to connect the service console

- - - Virtual Machine: used to connect virtual machines

- - The vNIC of a VM is connected to a port group on a vSwitch

- - A vSwitch with no associated pNIC creates an internal-only network

There's more...but that's a start

A pSwitch is, well....a pSwitch

Ken Cline

Technical Director, Virtualization

Wells Landers

TVAR Solutions, A Wells Landers Group Company

VMware Communities User Moderator

[Troy_Clavell]

have a look at this

http://www.vmware.com/files/pdf/virtual_networking_concepts.pdf

if you found this or any other post "helpful" or "correct" please consider awarding points

[vcpguy]

thanks a lot for the response. how, can I understand the trunking, when do I need to use it? And when should I not use it?

Why should, I request the networking guys to disable the STP on their Switch ?

Thanks

[Ken_Cline]

how, can I understand the trunking, when do I need to use it? And when should I not use it?

Use VLAN trunking when you need to have more network segments connected to your ESX host than you have pNICs. For example, if you have 6 pNICs installed, then by best practices you would have three vSwitches - one each for the vmkernel (VMotion), the service console, and the virtual machines. Each vSwitch would have two pNICs associated to provide redundancy. In this scenario, you would be able to connect your VMs to only one network segment unless you use VLAN tagging. So...in this example, if you had a need to connect a single VM to more than one network segment - or you needed to connect any VMs on the same host to more than one network segment, you would have to use VLAN tagging/trunking.

You should not use VLANs if your security group does not trust your network implementation.

Why should, I request the networking guys to disable the STP on their Switch ?

Because vSwitches do not participate in STP. They will ignore anything spanning tree related.

[vcpguy]

So, if I have 4 nics for the Virtual Machine and 3 VLANs and 1 Virtual Switch...From the Physical switch side, I need to configure those 4 ports as Trunk ports and on the Virtual Switch, should I configure different Virtual Machine portgroup policy, each configured with different VLANs ?

[Ken_Cline]

So, if I have 4 nics for the Virtual Machine and 3 VLANs and 1 Virtual Switch...From the Physical switch side, I need to configure those 4 ports as Trunk ports and on the Virtual Switch, should I configure different Virtual Machine portgroup policy, each configured with different VLANs ?

Yes. You would have something like this:

+-----------+                    +-----------+
|  pSwitch  |                    |  vSwitch  |
|   +-------|                    |-+       +-|
|   |Port 1 (VLAN A, B, C)         |       |
|   |---------------------[pNIC1]--|       |--[Port Group 1 (VLAN A)]--
|   |                              |       |
|   |Port 2 (VLAN A, B, C)         |       |
|   |---------------------[pNIC2]--|       |--[Port Group 2 (VLAN B)]--
|   |                              |       |
|   |Port 3 (VLAN A, B, C)         |       |
|   |---------------------[pNIC3]--|       |--[Port Group 3 (VLAN C)]--
|   |                              |       |
|   |Port 4 (VLAN A, B, C)         |       |
|   |---------------------[pNIC4]--|       |--[Port Group 4 (VLAN D)]--
|   +-------|                    |-+       +-|
+-----------+                    +-----------+