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

1 Introduction
HP Auto Port Aggregation (APA) is a software product that creates link aggregates, often called
trunks, which provide a logical grouping of two or more physical ports into a single fat pipe. This
port arrangement provides more data bandwidth than would otherwise be available and enables
you to build large bandwidth logical links into the server that are highly available and completely
transparent to the client and server applications. HP APA provides the following features:
• Automatic link failure detection and recovery
• Support for load balancing of network traffic across all of the links in the aggregation.
• Support for the creation of failover groups, providing a failover capability for links. In the
event of a link failure, LAN Monitor automatically migrates traffic to a standby link.
• Support for the TCP Segmentation Offload (Large Send) feature, if an aggregate is created
with all Ethernet cards capable of TCP Segmentation Offload (TSO).
• Support for the TCP segment reassembly (also known as TCP packet reassembly and Large
Receive Offload) combines TCP segments of data and passes the large, combined packet to
the upper layers of the network stack in the receive path. This can lower CPU utilization. This
feature is supported by 10GbE drivers only, if an aggregate is created with all Ethernet cards
capable of TCP segment reassembling.
• Support for Virtual VLANs (VLANs) over APA link aggregates and failover groups.
• Support for 64-bit MIB (RFC 2863) statistics, if all the interfaces within a link aggregate or
failover group support 64-bit statistics.
• Support for IPv6 addresses on a link aggregate or failover group.
• Support for the creation of failover groups over InfiniBand IPoIB ports.
• Support for the assignment of fixed MAC addresses for link aggregates and failover groups.
For release-specific information, see the HP Auto Port Aggregation (APA) Release Notes.
For a summary of HP APA capabilities, see Appendix A (page 76).
Conceptual overview
HP APA offers you a comprehensive solution to create fast, highly available network server
connections with minimal IT support costs. HP APA enables this with four key benefits:
• Automatic link failure detection and recovery in case of network failures. A link aggregate
continues to operate as long as there is at least one port operating.
• Scalable high-performance link aggregates using 100 BT/Gigabit Ethernet/10 Gigabit Ethernet
(also referred as 10GbE). See, “Load balancing” (page 8) for more information.
• Fault management and isolation with the HP MIB Monitor and nettl logging facilities.
• Lower IT costs with automated configuration and management tools using the IEEE 802.3ad
or PAgP standards and the intuitive HP System Management Homepage (SMH) GUI.
This section describes the following features of HP APA:
• Link aggregate
• Failover group
• TCP segmentation offload
• TCP Segment Reassembly (Large Receive Offload (LRO))
• VLAN support
Conceptual overview 7