Despite SR-IOV and vNIC, Shared Ethernet is still the most widely used virtualization solution, when it comes to virtualizing Ethernet. The POWER Hypervisor implements internal virtual IEEE802.1q compatible network switches, which, in conjunction with so-called shared Ethernet adapters or SEAs for short, take over the connection to external networks. The shared Ethernet adapters are implemented in software as a layer 2 bridge by the virtual I/O server.

As shown in figure 8.2, a shared Ethernet adapter can have several so-called trunking adapters. The SEA shown has the 3 trunking adapters ent8, ent9 and ent10, all 3 of which are connected to the virtual switch with the name ETHMGMT. In the case shown, all trunking adapters support VLAN tagging. In addition to the port VLAN IDs (PVIDs), the 3 trunking adapters also have additional VLANs via VLAN tagging. In addition to the connection to the virtual switch via the trunking adapter, the SEA also has a connection to an external network by the physical network adapter (ent0). Network packets from client LPARs to external systems are forwarded to the SEA via one of the trunking adapters and then to the external network via the associated physical network adapter. Network packets from external systems to client LPARs are forwarded by the SEA via the trunking adapter with the correct VLAN to the virtual switch, which then forwards the packets to the client LPAR.