Subject: Re: OSA-Express2 Device Addresses
From: Chris Mason (chrismason@belgacom.net)
Date: Sat Aug 29 2009 - 12:06:32 EDT
Tom Take a look at this redpaper for preliminary information regarding VSWITCH. Linux on IBM eServer zSeries and S/390: VSWITCH and VLAN Features of z/VM 4.4 http://www.redbooks.ibm.com/abstracts/redp3719.html This document tells me that zLinux is "fooled" into "thinking" that it is using real QDIO. I would very strongly expect that z/OS together with the z/OS Communications Server IP component as well as z/VSE together with any software providing an IP service would similarly be "fooled" into "thinking" they were using real QDIO. Recall that "fooling" into "thinking" that something *virtual* is *real* is the "raison d' tre" of z/VM and all its forebears. In case you haven't already you may wish to acquaint yourself with the following two manuals: - Open Systems Adapter-Express Customer's Guide and Reference, SA22-7935-10 - OSA-Express Implementation Guide, SG24-5948-05 Here is a pertinent abstract from the redbook: <quote> Question: How many devices should you define? The answer depends on the CHPID type, the number of TCP/IP stacks, the usage of the OSA-Express Network Traffic Analyzer and SNA definitions required. For the number of devices, consider the following: - Any OSD CHPID requires at least three devices (read, write, and datapath) for each TCP/IP stack. For z/OS, only the first TCP/IP stack requires three devices; any additional TCP/IP stack requires only one device (datapath). - If you plan to use the OSA-Express Network Traffic Analyzer (OSAENTA) function, you will need one additional data device. This data device is used to transmit the captured trace data to TCP/IP over a QDIO data device. - Any OSE CHPID requires two devices (read and write) for each TCP/IP. SNA requires one device. </quote> Chris Mason ----- Original Message ----- From: "Tom Rae" <tom_rae@shaw.ca> To: "VSE Discussion List" <vse-l@Lehigh.EDU> Sent: Saturday, August 29, 2009 5:21 AM Subject: Re: OSA-Express2 Device Addresses > Thanks, Mark. > > Initial input that I received suggested that z/VSE did not support virtual > NICs as required to couple to a VSWITCH. I will look into this further, > though, as a VSWITCH does sound more appealing. CP DEFINE NIC is supposed > to create "OSA-type" devices, which z/VSE may recognize as actual OSA > devices. > > The exclusion of xx00-xx02 and xxFE below was just due to the existing OSA > devices at these addresses... no black magic involved! > > Mark Post wrote: >> -snip- >> >>> One of the customers that I support is using vCTCAs to connect multiple >>> z/VSE and Linux guests to their z/VM TCP/IP and SNA SVMs. External >>> connections are provided by QDIO and non-QDIO OSA-Express2 devices (both >>> Gb and 1000Base-T) that are attached to the SVMs. We are looking at >>> providing more efficient, direct network access to the guests by >>> defining additional devices on the OSAs and attaching them directly to >>> the guests. >>> >> >> Why not use a VSWITCH instead? Far less systems programmer effort needed >> to maintain, automatic failover is provided by the VSWITCH controller, >> you can do Link Aggregation if needed, etc. >> >> >>> and that all of the new devices must be in the xx03-xxFD range. >>> >> >> I have never heard of this before. Unless you're saying that 00-02 and >> 0FE-0FF are already in use, but that would be specific to your situation, >> not a generic requirement. >> >>
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