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AH0054602-00 A
User’s Guide—Converged Network Adapters
QLogic 41
xxx
Series
iWARP
networking protocol that implements
RDMA for efficient data transfer over IP
networks. iWARP is designed for multiple
environments, including LANs, storage
networks, data center networks, and
WANs.
jumbo frames
Large IP frames used in high-performance
networks to increase performance over
long distances. Jumbo frames generally
means 9,000 bytes for Gigabit
but can refer to anything over the IP
,
which is 1,500 bytes on an Ethernet.
large send offload
See
Layer 2
Refers to the data link layer of the multilay-
ered communication model, Open
Systems Interconnection (OSI). The
function of the data link layer is to move
data across the physical links in a network,
where a switch redirects data messages at
the Layer 2 level using the destination
MAC address to determine the message
destination.
LSO
Large send offload. LSO Ethernet adapter
feature that allows the TCP\IP network
stack to build a large (up to 64KB) TCP
message before sending it to the adapter.
The adapter hardware segments the
message into smaller data packets
(frames) that can be sent over the wire: up
to 1,500 bytes for standard Ethernet
frames and up to 9,000 bytes for jumbo
Ethernet frames. The segmentation
process frees up the server CPU from
having to segment large TCP messages
into smaller packets that will fit inside the
supported frame size.
maximum transmission unit
.
message signaled interrupts
MSI, MSI-X
Message signaled interrupts. One of two
PCI-defined extensions to support
message signaled interrupts (MSIs), in
PCI 2.2 and later and PCI Express. MSIs
are an alternative way of generating an
interrupt through special messages that
allow emulation of a pin assertion or
deassertion.
MSI-X (defined in PCI 3.0) allows a device
to allocate any number of interrupts
between 1 and 2,048 and gives each inter-
rupt separate data and address registers.
Optional features in MSI (64-bit
addressing and interrupt masking) are
mandatory with MSI-X.
MTU
Maximum transmission unit. Refers to the
size (in bytes) of the largest packet (IP
datagram) that a specified layer of a
communications protocol can transfer.
