7.3.6. Virtual Networks
A very useful, but not very well known, feature of PowerVM, is the ability to give virtual networks a name. Each VLAN on each virtual switch is its own virtual network. The virtual networks (vnetwork) known on a managed system can be displayed using “ms lsvnetwork“:
$ ms lsvnetwork ms03
NAME VNETWORK VSWITCH TAGGED VLAN_ID
ms03 VLAN1-ETHERNET0 ETHERNET0 0 1
ms03 VLAN100-ETHERNET0 ETHERNET0 1 100
ms03 VLAN150-ETHERNET0 ETHERNET0 1 150
ms03 VLAN200-ETHERNET0 ETHERNET0 1 200
ms03 VLAN250-ETHERNET0 ETHERNET0 1 250
ms03 VLAN300-ETHERNET0 ETHERNET0 1 300
ms03 VLAN900-ETHERNET0 ETHERNET0 1 900
ms03 VLAN950-ETHERNET0 ETHERNET0 1 950
ms03 VLAN700-ETHNAS ETHNAS 0 700
$
When creating a virtual Ethernet adapter, virtual networks are created automatically, if they are not already available. By default, the string “VLAN” is used as the name, followed by the VLAN ID, a minus sign and the name of the virtual Ethernet switch. The name of the virtual network can be changed to any character string using the command “ms chvnetwork” (change virtual network) with the attribute new_name:
$ ms chvnetwork ms03 VLAN900-ETHERNET0 new_name=ManagementNet
$
Well-chosen names for the virtual networks (which are ultimately VLANs) can significantly simplify administration:
$ ms lsvnetwork ms03
NAME VNETWORK VSWITCH TAGGED VLAN_ID
ms03 VLAN1-ETHERNET0 ETHERNET0 0 1
ms03 ProductionDB ETHERNET0 1 100
ms03 TestDB ETHERNET0 1 150
ms03 Websphere-Prod ETHERNET0 1 200
ms03 Websphere-Test ETHERNET0 1 250
ms03 MQ-Network ETHERNET0 1 300
ms03 ManagementNet ETHERNET0 1 900
ms03 NIM-Network ETHERNET0 1 950
ms03 Netapp-Net ETHNAS 0 700
$
Tip: If names for the different VLANs are already used on the external switches, the same names should be used for the VLANs on the managed systems.
Another advantage of virtual networks is that the names can be specified directly when creating virtual Ethernet adapters, instead of switch names and VLAN IDs:
$ lpar addeth aix22 11 Netapp-Net
$
Additional (tagged) VLANs can also be specified using the virtual network name:
$ lpar -p standard addeth -i aix22 12 NIM-Network TestDB,Websphere-Test
$
If a virtual network is no longer in use, it is not automatically removed. To remove a virtual network which is not used any more, the command “ms rmvnetwork” (remove virtual network) can be used:
$ ms rmvnetwork ms03 MQ-Network
$
Of course, virtual networks can also be created manually, but this is usually not necessary. To create a virtual network manually with the command “ms addvnetwork” (add virtual network), the VLAN ID of the network must be specified in addition to the virtual switch:
$ ms addvnetwork ms03 testnet 999 ETHERNET0
$
The virtual network is created as a tagged network:
$ ms lsvnetwork -s vnetwork=testnet ms03
NAME VNETWORK VSWITCH TAGGED VLAN_ID
ms03 testnet ETHERNET0 1 999
$
If the virtual network is to be created as untagged, the option “-u” (untagged) can be used.