Latest Posts



Translate

Total Pageviews

Friday, 11 January 2013

VLAN configuration on virtual switches, physical switches, and virtual machines



Purpose

This article describes the various VLAN tagging methods used with ESXi/ESX.

Virtual LAN (VLAN) implementation is recommended in ESXi/ESX networking environments because:
  • It integrates ESXi/ESX into a pre-existing network
  • It secures network traffic
  • It reduces network traffic congestion
  • iSCSI traffic requires an isolated network

Resolution

  
 
There are three methods of VLAN tagging that can be configured on ESXi/ESX:

External Switch Tagging (EST)


Virtual Switch Tagging (VST)

  • All VLAN tagging of packets is performed by the virtual switch before leaving the ESXi/ESX host.
  • The ESXi/ESX host network adapters must be connected to trunk ports on the physical switch.
  • The portgroups connected to the virtual switch must have an appropriate VLAN ID specified.
  • For more information, see Configuring a VLAN on a portgroup (1003825).
  • For a sample of VST, see Sample configuration of virtual switch VLAN tagging (VST Mode) (1004074).
  • See this example snippet of code from a Cisco switch port configuration:

    switchport trunk encapsulation dot1q
    switchport mode trunk
    switchport trunk allowed vlan x,y,z
    spanning-tree portfast trunk
Note: The Native VLAN is not tagged and thus requires no VLAN ID to be set on the ESXi/ESX portgroup.

Virtual Guest Tagging (VGT)

  • All VLAN tagging is performed by the virtual machine.
  • You must install an 802.1Q VLAN trunking driver inside the virtual machine.
  • VLAN tags are preserved between the virtual machine networking stack and external switch when frames are passed to/from virtual switches.
  • Physical switch ports are set to trunk port.
  • For more information, see Sample configuration of virtual machine (VM) VLAN Tagging (VGT Mode) in ESX (1004252).
  • See this example snippet of code from a Cisco switch port configuration:

    switchport trunk encapsulation dot1q
    switchport mode trunk
    switchport trunk allowed vlan x,y,z
    spanning-tree portfast trunk


For additional information on these configurations, see VMware ESX Server 3: 802.1Q VLAN Solutions.
Source:-
http://kb.vmware.com/selfservice/microsites/search.do?cmd=displayKC&docType=kc&docTypeID=DT_KB_1_1&externalId=1003806