Most logical partitions in a Power System need access to an IP network, usually through Ethernet. However, it is not always possible or cost-effective to assign a physical Ethernet adapter to every logical partition in a Power System. Using Ethernet layer-2 bridging, a system administrator can connect a single partition to the physical Ethernet and then bridge all traffic between that network and one of the Power System’s virtual Ethernet LANs. Once the bridge is in place, any partition can access the physical network by using virtual Ethernet adapters on the bridged virtual LAN. Thus, Ethernet layer-2 bridging to the virtual LAN allows many logical partitions to share a single physical connection to the site network.
With IBM i 7.1, an IBM i partition can bridge a physical Ethernet port to the virtual LAN. This reduces hardware costs, since there are fewer Ethernet adapters required in the Power system, fewer ports required at the switch, and fewer cables to connect them. It may also reduce administration costs since there are fewer physical resources to manage, and this Ethernet sharing does not require a Virtual I/O Server partition, potentially reducing the number of environments that administrators need to manage.
In order to use Ethernet layer-2 bridging, users must have access to the management console for the system. The administrator must use the management console to create a virtual Ethernet adapter in the IBM i partition, indicating that the adapter will be used for external access. Then, the user creates two Ethernet line descriptions: one for the new virtual Ethernet adapter and one for the Ethernet port connected to the physical network. To establish the bridge, the user gives the two line descriptions the same bridge name, which is a new parameter on the CRTLINETH and CHGLINETH commands for the purposes of this support. When both line descriptions are active, traffic will be bridged between the two networks.