IBM 990 Reference Manual page 49

Two important networking technology advancements are
announced in z/VM 4.4 and Linux on z990:
• The high performance adapter interrupt handling fi rst
introduced with HiperSockets is now available for both
OSA-Express in QDIO mode (CHPID=OSD) and FICON
Express (CHPID=FCP). This advancement provides a
more effi cient technique for I/O interruptions designed
to reduce path lengths and overhead in both the host
operating system and in the adapter. This benefi ts OSA-
Express TCP/IP support in both Linux for zSeries and
z/VM.
• The z990's support of virtual machine technology has
been enhanced to include a new performance assist
for virtualization of adapter interruptions. This new z990
performance assist is available to V=V guests (pageable
guests) that support QDIO on z/VM 4.4. The deployment
of adapter interruptions improves effi ciency and per-
formance by reducing z/VM Control Program overhead
when handling Linux guest virtual servers.
HiperSockets
HiperSockets can be used for communication between
Linux images and Linux or z/OS images, whether Linux is
running in an IFL LPAR, natively or under z/VM.
Virtual Local Area Networks (VLANs), IEEE standard
802.1q, is offered for HiperSockets in a Linux on zSeries
environment. VLANs can reduce overhead by allowing
networks to be organized for optimum traffi c fl ow; the
network is organized by traffi c patterns rather than physi-
cal location. This enhancement permits traffi c to fl ow on
a VLAN connection both over HiperSockets and between
HiperSockets and an OSA-Express GbE, 1000BASE-T Eth-
ernet, or Fast Ethernet feature.
Internet Protocol Version 4 (IPv4) broadcast packets
are now supported over HiperSockets. TCP/IP applica-
tions that support IPv4 broadcast, such as OMPROUTE
when running Routing Information Protocol Version 1
(RIPv1), can send and receive broadcast packets over
HiperSockets interfaces. This support is exclusive to z990.
You can transparently bridge traffi c between a HiperSockets
and an external OSA-Express network attachment. New
Linux Layer 2 Switch (Linux L2S) support can help simplify
network addressing between HiperSockets and OSA-
Express. You can now seamlessly integrate HiperSockets-
connected operating systems into external networks,
without requiring intervening network routing overhead,
thus increasing performance and simplifying confi guration.
The currently available distributions; SUSE SLES 7, SUSE
SLES 8, Red Hat 7.1 and Red Hat 7.2 support z990
compatibility and exploitation of 30 LPARs and 2 Logical
Channel SubSystems. Support to further exploit z990 func-
tions will be delivered as an Open Source Contribution
via www.software.ibm.com/developerworks/opensource/
linux390/index.shtm. IBM is working with its distribution
partners to provide these functions in future distribution
releases.
Fibre Channel Protocol (FCP channel) Support for Linux
Support for FCP channels enables zSeries servers to
connect to select Fibre Channel Switches and FCP/SCSI
devices under Linux on zSeries. This expanded attachabil-
ity provides a larger selection of storage solutions for Linux
implementations.
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