Features
NetXtreme-E User’s Manual
February 26, 2018 • NetXtreme-E-UG100
Page 22
VXLAN
A Virtual eXtensible Local Area Network (VXLAN), defined in IETF RFC 7348, is used to address the need for
overlay networks within virtualized data centers accommodating multiple tenants. VXLAN is a Layer 2 overlay
or tunneling scheme over a Layer 3 network. Only VMs within the same VXLAN segment can communicate with
each other.
NVGRE/GRE/IP-in-IP/Geneve
Network Virtualization using GRE (NVGRE), defined in IETF RFC 7637, is similar to a VXLAN.
Stateless Offloads
RSS
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.
TPA
Transparent Packet Aggregation (TPA) is a technique where received frames of the same 4 tuple matched
frames are aggregated together and then indicated to the network stack. Each entry in the TPA context is
identified by the 4 tuple: Source IP, destination IP, source TCP port, and destination TCP port. TPA improves
system performance by reducing interrupts for network traffic and lessening CPU overhead.
Header-Payload 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.
UDP Fragmentation Offload
UDP Fragmentation Offload (UFO) is a feature that enables the software stack to offload fragmentation of UDP/
IP datagrams into UDP/IP packets. The support for this feature is only available in the Linux environment. The
following is a potential benefit of UFO:
•
The UFO enables the NIC to handle fragmentation of a UDP datagram into UDP/IP packets. This can result
in the reduction of CPU overhead for transmit side UDP/IP processing.
