<div dir="ltr"><div dir="ltr"></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Mon, May 4, 2020 at 3:31 AM Andrew Jeffery <<a href="mailto:andrew@aj.id.au">andrew@aj.id.au</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><br>
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On Thu, 30 Apr 2020, at 17:08, Deepak Kodihalli wrote:<br>
> On 30/04/20 4:21 am, Nancy Yuen wrote:<br>
> > I've talked with some people a while back (long while back) about <br>
> > multiple BMCs in a system. Either for redundancy or managing separate <br>
> > parts of a system. I'm wondering what other people are thinking in <br>
> > this area if at all.<br>
> > <br>
> > We are considering similar designs and I'm looking into options for <br>
> > BMC-BMC communications. Some BMCs may not be externally <br>
> > accessible. Here are some options that we've looked at:<br>
> > <br>
> > 1. i2c/IPMB<br>
> > 2. usbnet/Redfish<br>
> > 3. i2c/MCTP/PLDM or something else?<br>
> > 4. internal network via switch chip/Redfish or MCTP<br>
> > <br>
> > I'd like to reduce our use of IPMI so I want to avoid (1).<br>
> > <br>
> > ----------<br>
> > Nancy<br>
> <br>
> Hi Nancy,<br>
> <br>
> I think it depends on whether the BMCs need to talk to each other for <br>
> platform management, or if they manage their own hosts and we need one <br>
> of the BMCs to broadcast out of band requests and aggregate responses.<br>
> <br>
> For the former I think PLDM over MCTP could be a good fit. This is more <br>
> of an "inband" use-case in my opinion so I'm not sure if Redfish is well <br>
> suited. For the latter, a Redfish based aggregation is a good option.<br>
<br>
I think this looks like the right approach. Certainly some thought would be<br>
required in designing the MCTP networks given the (intentionally) limited<br>
number of endpoint IDs.<br>
<br>
Andrew<br></blockquote><div><br></div><div>Hi Andrew, Deepak,</div><div><br></div><div>Sorry for the delayed response!</div><div><br></div><div>For the purposes of this discussion I have BMCs managing their own host: BMC3<--->BMC2<--->BMC1/controller<--> external. I wrote BMC1 but there maybe some other controller there that isn't strictly a BMC. BMC2 would be "passing through" information between BMC1 and BMC3. But I don't necessarily want BMC2 to do any form of aggregation from information from BMC3. For BMC1/Controller and BMC 2 we are thinking Redfish. </div><div><br></div><div>In my case I'm interested in what ways people are thinking BMC2 and BMC3 should be connected and speaking to each other. Is MCTP/PLDM where everyone is leaning?</div><div><br></div><div><br></div><div><br></div></div></div>