Allied Telesis AT-2973T (NetExtreme II) - Manual (Page 19)

AT-2973SX and AT-2973T NetExtreme II Family Adapters Installation and User’s Guide
19
adapter, the TCP/IP processing can be moved to hardware, freeing the
CPU for more important tasks such as application processing.
The Broadcom NetXtreme II adapter's TOE functionality allows
simultaneous operation of up to 1024 fully offloaded TCP connections for
1-Gbps network adapters. The TOE support on the adapter significantly
reduces the host CPU utilization while preserving the implementation of
the operating system stack.
Note
The TOE feature is an optional feature that must be purchased.
Internet Small
Computer
Systems Interface
(iSCSI)
The IETF has standardized the Internet Small Computer Systems
Interface (iSCSI). SCSI is a popular protocol that enables systems to
communicate with storage devices, using block-level transfer (that is,
address data stored on a storage device that is not a whole file). iSCSI
maps the SCSI request/response application protocols and its
standardized command set over TCP/IP networks.
As iSCSI utilizes TCP as its sole transport protocol, it greatly benefits from
hardware acceleration of the TCP processing (that is, use of a TOE).
However, iSCSI as a Layer 5 protocol has additional mechanisms beyond
the TCP layer. iSCSI processing can also be offloaded, thereby reducing
CPU utilization even further.
The Broadcom NetXtreme II adapter targets best-system performance,
maintains system flexibility to changes, and supports current and future
OS convergence and integration. Therefore, the adapter's iSCSI offload
architecture is unique as evident by the split between hardware and host
processing.
Note
The iSCSI offload feature is an optional feature that must be
purchased.
Power
Management
When the system is down waiting for a wake-up signal, the adapter speed
connection may be at 10 Mbps or 100 Mbps, but it can return to 1000
Mbit/s when the system is up and running if it is connected to a 1000 Mbps
capable switch. For this reason, connect systems that use the Wake on
LAN (WOL) feature to a switch capable of both 1000 and 10/100 Mbps
speeds.
Note
The WOL feature is supported on the AT-2973T adapter only. It is
not supported on the AT-2973SX adapter. For more information, see
“Limitations” on page 52.