A brief overview of VMWare Network Interfaces i.e virtual/physical used in vSphere and NSX. Difference between vNIC, vmnic and vmk. what is port group?

1. VMWare Networking
vSphere Network Interface and VLAN Tagging

2. vNIC vs vmnic
vs vmk
• vNIC represents the virtual interface of VM used
for communication to other virtual or physical
machines. Functionally equivelant to a physical
interface in real world
• vmnic is in-fact physical interface of your ESXi
host, it carries traffic to outside world
• VMK is specialized VMWare interface used by
VMKernel TCP/IP Stack

3. VMKernel
Interfaces
• vmk0 procures the MAC address of
physical NIC and it is created during
installation of ESXi host
• vmk0 is management interface and an
IP address is required for
communication
• Other interfaces take up VMWare OUI
MAC Addresses
• Used for Management, vMotion,
storage and Fault Tolerance etc
• VMKernel adapters are disabled on the
default TCP/IP stack for vMotion
• Maximum 256 vmk can be created

4. Port Groups
Unlike Cisco and other vendors, VMWare uses
the term port group which functionally
equaivalent to VLAN with some added features
Port Groups are collection of virtual port on a
vSwitch
Since standard switch doesn’t expose
individual ports to apply policies, instead a
port group is used in policies.
Maximum 512 port groups can be configured
on standard switch

5. VLAN Tagging
EST
• VLAN ID 0
• External Switch Tagging
• Physical switch perform the tagging for
VLAN
• Virtual switch doesn’t pass traffic
associated with any VLAN. Basically
disables VLAN Tagging
• Physical switch port is an access port

6. VLAN Tagging-
Virtual Switch
Tagging
• VLAN ID Range 1-4094
• Virtual switch do the tagging before
packet exit ESXi host
• ESXi should be connected via trunk
port to remote physical switch

7. Virtual Guest
Tagging
• VLAN ID 4095
• VM performs the tagging, basically
switch’s job is moved to VM. Now VM
has more power
• VM should have 802.1Q VLAN trunking
driver installed
• Physical switch port is trunk
• VLAN tags created by VM is preserved
when packet traverse virtual switch