To understand the use of VLANs in an Exalogic environment, consider the following example scenario.
You want to combine Production, Test, and Development environments in the same Exalogic machine. However, you do not want these systems to communicate with each other directly. The production systems require dedicated Ethernet interfaces. You wish to share resources, such as Ethernet connectors, between Test and Development systems.
For the Production systems, you may dedicate a few of the external 10 GbE connectors on the gateway switch (for example, 0A-ETH-1 to 0A-ETH-4). Production systems will be on one VLAN using these four dedicated 10 GbE external uplinks.
For the Development systems, you may use one Ethernet connector on the gateway switch and a VLAN of their own. For example, 1A-ETH-3 associated with VLAN ID 10. In this VLAN, the resources using 1A-ETH-3 are dedicated to Development systems.
The Test systems require two Ethernet interfaces, and they can use Development's Ethernet connector 1A-ETH-3, but on a different VLAN. For example, you can create two Ethernet interfaces using 1A-ETH-3 associated with a VLAN ID 11 for use by the Test systems. In this manner, Development systems on their VLAN get their resources while sharing the Ethernet connector or uplink with Test systems. Since the two VLANs exist on the same 10 GbE Ethernet link on the gateway switch, any traffic between the two VLANs should travel through an external router if they are required to be seen by each other.
Note:
On a single Ethernet connection using the connector on the gateway switch, you can create up to 4094 VLANs.