Users Guide

12–Marvell Teaming Services
Teaming and Other Advanced Networking Properties
Doc No. BC0054508-00 Rev. R
January 21, 2021 Page 170 Copyright © 2021 Marvell
Checksum Offload
Checksum Offload is a property of the Marvell network adapters that allows the
TCP/IP/UDP checksums for send and receive traffic to be calculated by the
adapter hardware rather than by the host CPU. In high-traffic situations, this can
allow a system to handle more connections more efficiently than if the host CPU
were forced to calculate the checksums. This property is inherently a hardware
property and would not benefit from a software-only implementation. An adapter
that supports Checksum Offload advertises this capability to the operating system
so that the checksum does not need to be calculated in the protocol stack.
Checksum Offload is only supported for IPv4 at this time.
IEEE 802.1p QoS Tagging
The IEEE 802.1p standard includes a 3-bit field (supporting a maximum of
8 priority levels), which allows for traffic prioritization.
Large Send Offload
Large Send Offload (LSO) is a feature provided by Marvell network adapters that
prevents an upper level protocol such as TCP from breaking a large data packet
into a series of smaller packets with headers appended to them. The protocol
stack need only generate a single header for a data packet as large as 64 KB, and
the adapter hardware breaks the data buffer into appropriately-sized Ethernet
frames with the correctly sequenced header (based on the single header originally
provided).
Jumbo Frames
The use of jumbo frames was originally proposed by Alteon Networks, Inc. in 1998
and increased the maximum size of an Ethernet frame to a maximum size of 9600
bytes. Though never formally adopted by the IEEE 802.3 Working Group, support
for jumbo frames has been implemented in Marvell 57xx and 57xxx adapters. The
QLASP intermediate driver supports jumbo frames, provided that all of the
physical adapters in the team also support jumbo frames and the same size is set
on all adapters in the team.