Users Guide
Table Of Contents
- Table of Contents
- 1 Regulatory and Safety Approvals
- 2 Functional Description
- 3 Network Link and Activity Indication
- 4 Features
- 4.1 Software and Hardware Features
- 4.2 Virtualization Features
- 4.3 VXLAN
- 4.4 NVGRE/GRE/IP-in-IP/Geneve
- 4.5 Stateless Offloads
- 4.6 Priority Flow Control
- 4.7 Virtualization Offload
- 4.8 SR-IOV
- 4.9 Network Partitioning (NPAR)
- 4.10 Security
- 4.11 RDMA over Converged Ethernet – RoCE
- 4.12 VMWare Enhanced Networking Stack (ENS)
- 4.13 Supported Combinations
- 4.14 Unsupported Combinations
- 5 Installing the Hardware
- 6 Software Packages and Installation
- 7 Updating the Firmware
- 8 Link Aggregation
- 9 System-Level Configuration
- 10 PXE Boot
- 11 SR-IOV – Configuration and Use Case Examples
- 12 NPAR – Configuration and Use Case Example
- 13 Tunneling Configuration Examples
- 14 RoCE – Configuration and Use Case Examples
- 15 DCBX – Data Center Bridging
- 16 DPDK – Configuration and Use Case Examples
- Revision History
Broadcom NetXtreme-E-UG304-2CS
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NetXtreme-E User Guide User Guide for Dell Platforms
4.5.5 Header and Data Split
Header-payload split is a feature that enables the software TCP/IP stack to receive TCP/IP packets with header and payload
data split into separate buffers. The support for this feature is available in both Windows and Linux environments. The
following are potential benefits of header-payload split:
The header-payload split enables compact and efficient caching of packet headers into host CPU caches. This can
result in a receive side TCP/IP performance improvement.
Header-payload splitting enables page flipping and zero copy operations by the host TCP/IP stack. This can further
improve the performance of the receive path.
4.5.6 VLAN Tag Insertion and Removal
On the TX Path, the Ethernet controller is capable of inserting IEEE 802.1Q-compliant VLAN tags into transmitted frames
and extracting the VLAN tags from received frames.
On the RX path, receiving VLAN-tagged (IEEE 802.1q-compliant) packets is supported by the Ethernet controller. If a
function is configured to strip VLAN tag, then the VLAN tag is stripped from the IEEE 802.1q-compliant packet at reception
and placed in a receive completion record.
4.5.7 Packet Steering
4.5.7.1 Receive Side Scaling (RSS)
RSS is a scalable networking technology that enables receive packet processing to be balanced across multiple processors
in the system while maintaining in-order delivery of the data. RSS enables different packets, received by a single network
adapter, to be processed on different CPUs/cores in parallel while preserving in-order delivery of TCP connections.
Receive Side Scaling (RSS) uses a Toeplitz algorithm which uses 4-tuple match on the received frames and forwards it to
a deterministic CPU for frame processing. This allows streamlined frame processing and balances CPU utilization. An
indirection table is used to map the stream to a CPU.
Symmetric RSS allows the mapping of packets of a given TCP or UDP flow to the same receive queue.
4.5.7.2 Accelerated Receive Flow Steering
Accelerated RFS (aRFS, or RFS) is an Ethernet controller feature that improves packet reception efficiency by delivering
packets to queues based on CPU locality of the application. This reduces memory access latency and improves
performance. Accelerated RFS takes precedence over RSS when enabled and configured. If the incoming flow does not
match any existing n-tuple filters, it is steered according to the RSS hash.
4.5.8 Data Center Bridging
Data Center Bridging (DCB) is a set of protocols and capabilities (for example, DCBX, LLDP, ETS, and PFC) for use in a
data center environment. The NetXtreme-E family of Ethernet controllers support for priority flow control is described in
section on Priority Flow Control.