Host Ethernet Adapter

A Host Ethernet Adapter (HEA) is a physical Ethernet adapter that is integrated directly into the GX+ bus on a managed system. HEAs offer high throughput, low latency, and virtualization support for Ethernet connections. HEAs are also known as Integrated Virtual Ethernet adapters (IVE adapters).

Note: HEA is not supported on POWER8® processor-based server.

Unlike most other types of I/O devices, you can never assign the HEA itself to a logical partition. Instead, multiple logical partitions can connect directly to the HEA and use the HEA resources. This allows these logical partitions to access external networks through the HEA without having to go through an Ethernet bridge on another logical partition.

To connect a logical partition to an HEA, you must create a logical Host Ethernet Adapter (LHEA) for the logical partition. A logical Host Ethernet Adapter (LHEA) is a representation of a physical HEA on a logical partition. An LHEA appears to the operating system as if it were a physical Ethernet adapter, just as a virtual Ethernet adapter appears as if it were a physical Ethernet adapter. When you create an LHEA for a logical partition, you specify the resources that the logical partition can use on the actual physical HEA. Each logical partition can have one LHEA for each physical HEA on the managed system. Each LHEA can have one or more logical ports, and each logical port can connect to a physical port on the HEA.

You can create an LHEA for a logical partition using either of the following methods:

You can add the LHEA to a partition profile, shut down the logical partition, and reactivate the logical partition using the partition profile with the LHEA.
You can add the LHEA to a running logical partition using dynamic partitioning. This method can be used for Linux logical partitions only if you install the following operating systems on the logical partition:
- Red Hat Enterprise Linux version 4.6, or later
- Red Hat Enterprise Linux version 5.1, or later
- SUSE Linux Enterprise Server Version 10, or later
- SUSE Linux Enterprise Server Version 11, or later

When you activate a logical partition, the LHEAs in the partition profile are considered to be required resources. If the physical HEA resources required by the LHEAs are not available, then the logical partition cannot be activated. However, when the logical partition is active, you can remove any LHEAs you want from the logical partition. For every active LHEA that you assign to an IBM® i logical partition, IBM i requires 40 MB of memory.

After you create an LHEA for a logical partition, a network device is created in the logical partition. This network device is named entX on AIX® logical partitions, CMNXX on IBM i logical partitions, and ethX on Linux logical partitions, where X represents sequentially assigned numbers. The user can then set up TCP/IP configuration like a physical Ethernet device to communicate with other logical partitions.

You can configure a logical partition so that it is the only logical partition that can access a physical port of an HEA by specifying promiscuous mode for an LHEA that is assigned to the logical partition. When an LHEA is in promiscuous mode, no other logical partitions can access the logical ports of the physical port that is associated with the LHEA that is in promiscuous mode. You might want to configure a logical partition to promiscuous mode in the following situations:

If you want to connect more than 16 logical partitions to each other and to an external network through a physical port on an HEA, you can create a logical port on a Virtual I/O Server and configure an Ethernet bridge between the logical port and a virtual Ethernet adapter on a virtual LAN. This allows all logical partitions with virtual Ethernet adapters on the virtual LAN to communicate with the physical port through the Ethernet bridge. If you configure an Ethernet bridge between a logical port and a virtual Ethernet adapter, the physical port that is connected to the logical port must have the following properties:
- The physical port must be configured so that the Virtual I/O Server is the promiscuous mode logical partition for the physical port.
- The physical port can have only one logical port.
You want the logical partition to have dedicated access to a physical port.
You want to use tools such as tcpdump or iptrace.

A logical port can communicate with all other logical ports that are connected to the same physical port on the HEA. The physical port and its associated logical ports form a logical Ethernet network. Broadcast and multicast packets are distributed on this logical network as though it was a physical Ethernet network. You can connect up to 16 logical ports to a physical port using this logical network. By extension, you can connect up to 16 logical partitions to each other and to an external network through this logical network. The actual number of logical ports that you can connect to a physical port depends upon the Multi-Core Scaling value of the physical port group. It also depends on the number of logical ports that have been created for other physical ports within the physical port group. By default, the Multi-Core Scaling value of each physical port group is set to 4, which allows four logical ports to be connected to the physical ports in the physical port group. To allow up to 16 logical ports to be connected to the physical ports in the physical port group, you must change the Multi-Core Scaling value of the physical port group to 1 and restart the managed system.

You can set each logical port to restrict or allow packets that are tagged for specific VLANs. You can set a logical port to accept packets with any VLAN ID, or you can set a logical port to accept only the VLAN IDs that you specify. You can specify up to 20 individual VLAN IDs for each logical port.

The physical ports on an HEA are always configured on the managed system level. If you use an HMC to manage a system, you must use the HMC to configure the physical ports on any HEAs belonging to the managed system. Also, the physical port configuration applies to all logical partitions that use the physical port. (Some properties might require setup in the operating system as well. For example, the maximum packet size for a physical port on the HEA must be set on the managed system level using the HMC. However, you must also set the maximum packet size for each logical port within the operating system.) By contrast, if a system is unpartitioned and is not managed by an HMC, you can configure the physical ports on an HEA within the operating system as if the physical ports were ports on a regular physical Ethernet adapter.

HEA hardware does not support half duplex mode.

You can change the properties of a logical port on an LHEA by using dynamic partitioning to remove the logical port from the logical partition. You can also add the logical port back to the logical partition using the changed properties. If the operating system of the logical partition does not support dynamic partitioning for LHEAs, and you want to change any logical port property other than the VLANs on which the logical port participates, you must set a partition profile for the logical partition so that the partition profile contains the wanted logical port properties, shut down the logical partition, and activate the logical partition using the new or changed partition profile. If the operating system of the logical partition does not support dynamic partitioning for LHEAs, and you want to change the VLANs on which the logical port participates, you must remove the logical port from a partition profile belonging to the logical partition, shut down and activate the logical partition using the changed partition profile, add the logical port back to the partition profile using the changed VLAN configuration, and shut down and activate the logical partition again using the changed partition profile.

Last updated: Fri, July 05, 2019