NOTE: The December 2005 and later releases of APA for
•The physical ports in the link aggregation use the same MAC address.
The unique MAC address for a specific link aggregate is determined by using the MAC address of one of the ports in the link aggregate. All ports will use the same MAC address.
When a physical port is removed from a link aggregate, the port's MAC address is reset to its own MAC address.
•HP APA link aggregates can migrate the network traffic from a failed physical link in the aggregate to the remaining operational links in the aggregate.
•HP APA distributes the outbound network traffic across the physical links in the link aggregation using a load balancing algorithm.
Effective APA load balancing requires many simultaneous, active client connections. The connections are distributed across the physical links. One client connection will have its traffic sent on one physical link. The connection is defined by the
•Each link aggregate can have one or more IP addresses assigned to it in the /etc/ rc.config.d/netconf file.
•The link partner (the switch, router, or server) ports connected to the server ports must be configured for link aggregation (trunking). In addition, the mode on the link partner and the server must be the same. For example, if ports 1, 2, 3, and 4 are connected to a link partner switch's ports C1, C2, C3, and C4, respectively, and the server side is trunked using LACP_AUTO mode, the partner switch must be configured to trunk ports C1, C2, C3, and C4 using LACP_AUTO mode.
NOTE: MANUAL mode link aggregates using HOT_STANDBY load balancing can be connected to different switches. In addition, do not enable trunking on the corresponding switch ports.
•The link partner (the switch, router, or server) connected to the link aggregation can inhibit the usefulness of HP APA in some environments. See “HP APA Configuration Examples” (page 23) for more information.
•All the devices in the link aggregation must be the same type and must be configured for the same speed, duplex, and MTU. See “Supported LAN Cards” (page 19) for the devices HP APA supports.
Load Balancing
HP APA provides load balancing on outbound data transfers using a load distribution algorithm that you select when you configure a link aggregate. The load distribution algorithms are based on destination MAC address, IP address, or TCP/UDP port number. Inbound load balancing is strictly determined by the link partner (switch, router, or remote server) and has no affect on the outbound algorithms.
Although you can use each of these load distribution algorithms in all supported configurations, they may not all provide the same load on each of the physical ports in the link aggregate. Therefore, HP prefers you use the algorithm that is recommended for each supported configuration. See “Preparing for Configuration” (page 31) for more information.
The load balancing algorithm consists of the following steps:
14 Introduction