Introduction to vSphere Networking
At the core of vSphere Networking are virtual switches. vSphere supports standard switches (VSS) and distributed switches (VDS). Each virtual switch has a preset number of ports and one or more port groups.
Virtual switches allow your virtual machines to connect to each other and to connect to the outside world.
Virtual switches allow your ESXi host to migrate virtual machines with VMware vMotion and to use IP storage through VMkernel network interfaces.
Using vMotion, you can migrate running virtual machines with no downtime. You can enable vMotion with vicfg-vmknic --enable-vmotion. You cannot enable vMotion with ESXCLI.
The network services that the VMkernel provides (iSCSI, NFS, and vMotion) use a TCP/IP stack in the VMkernel. The VMkernel TCP/IP stack is also separate from the guest operating system’s network stack. Each of these stacks accesses various networks by attaching to one or more port groups on one or more virtual switches.
Networking Using vSphere Standard Switches
vSphere standard switches allow you to connect virtual machines to the outside world.
Networking with vSphere Standard Switches
Networking with vSphere Standard Switches shows the relationship between the physical and virtual network elements. The numbers match those in the figure.
Associated with the standard switch are port groups (3). Port group is a unique concept in the virtual environment. You can configure port groups to enforce policies that provide enhanced networking security, network segmentation, better performance, high availability, and traffic management. You can use the esxcli network vswitch standard portgroup or vicfg-vswitch command to associate a standard switch with a port group, and the esxcli network ip interface or vicfg-vmknic command to associate a port group with a VMkernel network interface.
The VMkernel TCP/IP networking stack supports iSCSI, NFS, and vMotion and has an associated VMkernel network interface. You configure VMkernel network interfaces with esxcli network ip interface or vicfg-vmknic. See Adding and Modifying VMkernel Network Interfaces. Separate VMkernel network interfaces are often used for separate tasks, for example, you might devote one VMkernel Network interface card to vMotion only. Virtual machines run their own systems’ TCP/IP stacks and connect to the VMkernel at the Ethernet level through virtual switches.
Networking Using vSphere Distributed Switches
When you want to connect a virtual machine to the outside world, you can use a standard switch or a distributed switch. With a distributed switch, the virtual machine can maintain its network settings even if the virtual machine is migrated to a different host.
Networking with vSphere Distributed Switches
Like a standard switch, each distributed switch is a network hub that virtual machines can use. A distributed switch can route traffic internally between virtual machines or link to an external network by connecting to physical network adapters. You create a distributed switch using the vSphere Client UI, but can manage some aspects of a distributed switch with vicfg-vswitch. You can list distributed virtual switches with the esxcli network vswitch command. See Setting Up Virtual Switches and Associating a Switch with a Network Interface.