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<p class="MsoNormal">Redfish defines computer system to be multiple chassis or multiple blades within a chassis. It would be good to clarify if you are referring to “System” as:<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<ul style="margin-top:0in" type="disc">
<li class="MsoListParagraph" style="margin-left:0in;mso-list:l0 level1 lfo4">Multiple chassis with their own BMCs ( Storage, Compute, GPU etc )
<o:p></o:p></li><li class="MsoListParagraph" style="margin-left:0in;mso-list:l0 level1 lfo4">Multiple Blades with their own BMC within a chassis.
<o:p></o:p></li></ul>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Neeraj<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal"><b>From:</b> openbmc <openbmc-bounces+neladk=microsoft.com@lists.ozlabs.org>
<b>On Behalf Of </b>Vijay Khemka<br>
<b>Sent:</b> Wednesday, April 29, 2020 5:16 PM<br>
<b>To:</b> Nancy Yuen <yuenn@google.com>; OpenBMC Maillist <openbmc@lists.ozlabs.org><br>
<b>Subject:</b> [EXTERNAL] Re: Multiple BMCs in a system: IPMB? Redfish? MCTP?<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Hi Nancy,<o:p></o:p></p>
<p class="MsoNormal">We are currently using (1) in our current multi host design. Option (3) also looks good.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Regards<o:p></o:p></p>
<p class="MsoNormal">-Vijay<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal"><b><span style="font-size:12.0pt;color:black">From: </span></b><span style="font-size:12.0pt;color:black">openbmc <<a href="mailto:openbmc-bounces+vijaykhemka=fb.com@lists.ozlabs.org">openbmc-bounces+vijaykhemka=fb.com@lists.ozlabs.org</a>>
on behalf of Nancy Yuen <<a href="mailto:yuenn@google.com">yuenn@google.com</a>><br>
<b>Date: </b>Wednesday, April 29, 2020 at 3:53 PM<br>
<b>To: </b>OpenBMC Maillist <<a href="mailto:openbmc@lists.ozlabs.org">openbmc@lists.ozlabs.org</a>><br>
<b>Subject: </b>Multiple BMCs in a system: IPMB? Redfish? MCTP?<o:p></o:p></span></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">I've talked with some people a while back (long while back) about multiple BMCs in a system. Either for redundancy or managing separate parts of a system. I'm wondering what other people are thinking in this area if at all.<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">We are considering similar designs and I'm looking into options for BMC-BMC communications. Some BMCs may not be externally accessible. Here are some options that we've looked at:<o:p></o:p></p>
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<ol start="1" type="1">
<li class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;mso-list:l2 level1 lfo3">
i2c/IPMB<o:p></o:p></li><li class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;mso-list:l2 level1 lfo3">
usbnet/Redfish<o:p></o:p></li><li class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;mso-list:l2 level1 lfo3">
i2c/MCTP/PLDM or something else?<o:p></o:p></li><li class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;mso-list:l2 level1 lfo3">
internal network via switch chip/Redfish or MCTP<o:p></o:p></li></ol>
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<p class="MsoNormal"> I'd like to reduce our use of IPMI so I want to avoid (1).<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">----------<br>
Nancy<o:p></o:p></p>
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