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• 640 TCP/IP stacks
• Concurrent LIC update
• SC Duplex connector
• Single mode fi ber (9 micron)
• An unrepeated distance of up to 10 km (6.2 miles)
Checksum Offl oad is supported in the z/OS, z/OS.e and
Linux on zSeries environments.
The 10 Gigabit Ethernet (10 GbE) feature does not support
auto-negotiation to any other speed. The 10 GbE supports
64B/66B coding, whereas GbE supports 8B/10B coding.
The OSA-Express2 10 GbE feature is exclusive to the z890
and z990, and requires the October 2004 level of Licensed
Internal Code.
New functions in OSA-Express2
In a continuing effort to enhance the functions of the Open
Systems Adapters and respond to customer requirements,
IBM zSeries has enhanced the OSA-Express2 over OSA-
Express features with the following improvements:
Improved virtualization – now 640 TCP/IP stacks
If you have a need to host more Linux images, increasing
the number of TCP/IP stacks may be a solution. The OSA-
Express2 features support up to 640 connections (TCP/IP
stacks) per logical partition (LPAR) per dedicated CHPID,
or up to 640 total stacks across multiple LPARs using a
shared or spanned CHPID. This is 4 times the number of
connections that could be supported on the previous OSA-
Express features which were limited to 160 total stacks.
This support is exclusive on z890 and z990 servers and
the OSA-Express2 features in QDIO mode. This support
requires the October 2004 level of Licensed Internal Code
and is supported by z/OS, z/OS.e, z/VM and Linux on
zSeries environments.
Large send for TCP/IP traffi c
Large send, also referred to as TCP segmentation offl oad,
is designed to improve performance by offl oading TCP
packet processing from the z890 and z990 servers to the
OSA-Express2 features. This offl oad allows the zSeries
server to send large blocks of data (64 kilobytes), instead
of 1492 byte packets, to the OSA-Express2 feature. The
OSA-Express2 features then separate the 64 KB block into
standard Ethernet packets (1492 bytes) to be sent out on
the LAN. This applies only to outbound traffi c, IPv4 or IPv6,
and to unicasts. Large send support can help reduce host
processor utilization, returning CPU cycles for other appli-
cation use, while increasing network effi ciencies.
Large send support is exclusive to z890 and z990 servers
with the OSA-Express2 features, when in QDIO mode, and
is supported on Linux for zSeries (requires the October
2004 level of Licensed Internal Code).
OSA-Express2 large send for the z/OS environment –
preview
Previewing large send for TCP/IP traffi c
z/OS Communications Server plans to exploit OSA-
Express2 large send (also referred to as TCP segmenta-
tion offl oad). Large send can improve performance by
offl oading outbound TCP segmentation processing from
the host to OSA-Express2 by employing a more effi cient
memory transfer into OSA-Express2. The z/OS Communi-
cations Server support is planned for TCP/IP IPv4 traffi c
only and z/OS and z/OS.e 1.7. In addition, a z/OS and
z/OS.e 1.6 PTF is planned to be provided.
Large send support applies to the OSA-Express2 features
(Gigabit Ethernet SX and LX, 10 Gigabit Ethernet LR), sup-
ports QDIO mode only (CHPID type OSD), and is exclu-
sive to z990 and z890. Large send support was previously
announced for the Linux on zSeries environment.