TCP/IP techniques connecting virtual Ethernet to external LANs

You can take advantage of virtual Ethernet on i5/OS™.

If you are using a virtual Ethernet network for interpartition communication, you may need to enable these partitions to communicate with a physical, external LAN. There are several ways to connect the virtual Ethernet network to an external LAN using different TCP/IP techniques. You need to enable the TCP/IP traffic to flow between the virtual Ethernet network and the external LAN. This figure shows a logical flow of the IP packets.

IP traffic initiated by Partition A goes from its virtual Ethernet interface to the virtual Ethernet interface on Partition B. By implementing any one of the three TCP/IP techniques described below, you can enable the IP packets to continue on to the external interface and toward their destination.

• Proxy Address Resolution Protocol method
  This proxy Address Resolution Protocol (ARP) method uses transparent subnetting to associate a partition's virtual interface with an external interface. Proxy ARP function is built into the TCP/IP stack. If you have the necessary IP addresses, this approach is recommended.
• Network address translation method
  You can use i5/OS packet filtering to route traffic between a partition and the outside network.
• TCP/IP routing method
  Standard TCP/IP routing is used to route traffic to the virtual Ethernet network in the same way you define routing to any other LAN. This requires that you update routing information throughout your network.
• Virtual Ethernet considerations
  You can use virtual Ethernet as an alternative to using a network card for interpartition communication.