VMware vSphere has a set of virtual networking elements that lets you network the virtual machines in the data center like a physical environment.

Networking with vNetwork Standard Switches
Represents networking with vNetwork standard switches and shows the relationshop between networks inside and outside of the virtual environment are represented.

Networking with vNetwork Standard Switches shows the relationship between the networks inside and outside the virtual environment for vSwitches. The virtual environment provides networking elements similar to the physical world. They are virtual network interface cards (vNIC), vNetwork Standard Switches (vSwitch), vNetwork Distributed Switches (dvSwitch), and port groups. dvSwitch networking is shown in Networking with vNetwork Distributed Switches.

Like a physical machine, each virtual machine has one or more vNICs. The guest operating system and application programs communicate with a vNIC through either a commonly available device driver or a VMware device driver optimized for the virtual environment. In either case, communication in the guest operating system occurs just as it would with a physical device. Outside the virtual machine, the vNIC has its own MAC address and one or more IP addresses, and responds to the standard Ethernet protocol as would a physical NIC. An outside agent does not detect that it is communicating with a virtual machine.

A virtual switch works like a layer 2 physical switch. Each server has its own virtual switches. On one side of the virtual switch are port groups that connect to virtual machines. On the other side are uplink connections to physical Ethernet adapters on the server where the virtual switch resides. Virtual machines connect to the outside world through the physical Ethernet adapters that are connected to the virtual switch uplinks.

A virtual switch can connect its uplinks to more than one physical Ethernet adapter to enable NIC teaming. With NIC teaming, two or more physical adapters can be used to share the traffic load or provide passive failover in the event of a physical adapter hardware failure or a network outage. For information on NIC teaming, see the ESX Configuration Guide or ESXi Configuration Guide.

A vNetwork Distributed Switch (dvSwitch) functions as a single virtual switch across all associated hosts. This allows virtual machines to maintain consistent network configuration as they migrate across multiple hosts. Like a vSwitch, each dvSwitch is a network hub that virtual machines can use. A vSwitch can route traffic internally between virtual machines or link to an external network by connecting to physical Ethernet adapters. Each vSwitch can also have one or more dvPort groups assigned to it. dvPort groups aggregate multiple ports under a common configuration and provide a stable anchor point for virtual machines connecting to labeled networks.

Networking with vNetwork Distributed Switches
Represents networking with vNetwork Distributed switches and shows the relationshop between networks inside and outside of the virtual environment are represented.

Port group is a unique concept in the virtual environment. A port group is a mechanism for setting policies that govern the network connected to it. A vSwitch can have multiple port groups. Instead of connecting to a particular port on the vSwitch, a virtual machine connects its vNIC to a port group. All virtual machines that connect to the same port group belong to the same network inside the virtual environment even if they are on different physical servers.

You can configure port groups to enforce policies that provide enhanced networking security, network segmentation, better performance, high availability, and traffic management.

Layer 2 security options

Enforces what vNICs attached to a port group in a virtual machine can do by controlling capabilities for a promiscuous mode, MAC address changes, or forged transmissions.

VLAN support

Integrates virtual networks with physical network VLANs.

Private VLAN

Allows use of VLAN IDs within a private network without having to worry about duplicating VLAN IDs across a wider network.

Traffic shaping

Defines QOS policies for average and peak bandwidth, and traffic burst size. You set policies to improve traffic management.

NIC teaming

Sets the NIC teaming policies for an individual port group or network to share traffic load or provide failover in case of hardware failure.