Functionality and Features: Broadcom NetXtreme II Network Adapter User Guide
file:///T|/htdocs/NETWORK/BroadCom/71921/NetXtremeII/en/features.htm[9/26/2012 3:28:28 PM]
The TCP/IP protocol suite is used to provide transport services for a wide range of applications for the Internet, LAN, and for
file transfer. Without the TCP Offload Engine, the TCP/IP protocol suite runs on the host CPU, consuming a very high
percentage of its resources and leaving little resources for the applications. With the use of the Broadcom NetXtreme II
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 and 1880 fully offloaded TCP connections for 10-Gbps network adapters. The TOE
support on the adapter significantly reduces the host CPU utilization while preserving the implementation of the operating
system stack.
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 (i.e., 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 (i.e.,
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.
NOTES: The iSCSI offload feature is not available for all Broadcom network adapters.
Fibre Channel over Ethernet
FCoE (Fibre Channel Backbone-5 (FC-BB-5)) allows Fibre Channel protocol to be transferred over Ethernet. FCoE preserves
existing Fibre Channel infrastructure and capital investments. The following FCoE features are supported:
Full stateful hardware FCoE offload
Receiver classification of FCoE and FIP frames. FIP is the FCoE Initialization Protocol used to establish and maintain
connections.
Receiver CRC offload
Transmitter CRC offload
Dedicated queue set for Fibre Channel traffic
Data Center Bridging (DCB) provides lossless behavior with Priority Flow Control (PFC)
DCB allocates a share of link bandwidth to FCoE traffic with Enhanced Transmission Selection (ETS)
NOTES: FCoE is not available for all Broadcom network adapters.
Power Management
Adapter speed connection when the system is down waiting for a wake-up signal may be at 10 Mbps or 100 Mbps, but can
return to 1000 Mbit/s when the system is up and running if connected to a 1000 Mbps capable switch. Systems intending to
use Wake on LAN (WOL) should be connected to a switch capable of both 1000 and 10/100 Mbps speeds.
NOTES:
Dell supports WOL on only one adapter in the system at a time.
For specific systems, see your system documentation for WOL support.
WOL is supported in Broadcom NetXtreme II BCM5708 devices with silicon revisions of B2 or later. For more
information, see
Limitations
.
Adaptive Interrupt Frequency
The adapter driver intelligently adjusts host interrupt frequency based on traffic conditions to increase overall application
