HiperSockets

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 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 trafﬁc 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.