How a Virtual Network Works

The following figure shows the working of a virtual network and its components in a system.

Figure 1-2  Working of a Virtual Network

The figure shows a single system with one NIC. The NIC is configured with three VNICs. Each VNIC is assigned to a zone. Zone 1, Zone 2, and Zone 3 are the three zones configured for use in the system. The zones communicate with each other and with the external network by using their respective VNICs. The three VNICs connect to the underlying physical NIC through the virtual switch. The function of a virtual switch is equivalent to the function of a physical switch as both provide connectivity to the systems.

When a virtual network is configured, a zone sends traffic to an external host in the same way as a system without a virtual network. Traffic flows from the zone, through the VNIC to the virtual switch, and then to the physical interface, which sends the data to the network.

The zones can also exchange traffic with one another inside the system if all the VNICs configured to the zones are part of the same VLAN. For example, packets pass from Zone 1 through its dedicated VNIC 1. The traffic then flows through the virtual switch to VNIC 3. VNIC 3 then passes the traffic to Zone 3. The traffic never leaves the system, and therefore never violates the Ethernet restrictions.

Alternatively, you can create a virtual network based on the etherstub. Etherstubs are entirely software based and do not require a network interface as the basis for the virtual network.

Oracle also provides the Oracle Enterprise Manager Ops Center for managing some aspects of network virtualization, for example, the ability to create virtual networks inside a virtual data center. For more information about the Oracle Enterprise Manager Ops Center, see the documentation library at http://www.oracle.com/pls/topic/lookup?ctx=oc122&id=OPCCM.