HP Auto Port Aggregation Administrator's Guide HP-UX 11i v3 (766140-001, March 2014)

• Interoperability with HP Serviceguard
• Administrative methods
Link aggregate
HP APA enables you to combine multiple physical link ports into one. This gives the link aggregation
a theoretical bandwidth of 8 times that of a single physical link (32 times for LACP mode). For
maximum number of links for each link aggregate, see the APA Support Matrix A link aggregate
has the following characteristics:
• The physical ports in the link aggregation use the same MAC address.
By default, 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. HP APA enables you to assign a fixed MAC address for the link aggregate. For
more information on assigning a fixed MAC address for link aggregates, see “Editing files
for FEC_AUTO or LACP_AUTO mode” (page 85).
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 load-balancing algorithm. See
“Load balancing” (page 8) for more information.
• 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 is deprecated and will be obsolete in future HP UX releases.
• 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 17) 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 14) 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.
8 Introduction