Multiple BMCs in a system: IPMB? Redfish? MCTP?
andrew at aj.id.au
Mon May 4 20:30:10 AEST 2020
On Thu, 30 Apr 2020, at 17:08, Deepak Kodihalli wrote:
> On 30/04/20 4:21 am, Nancy Yuen wrote:
> > 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.
> > 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:
> > 1. i2c/IPMB
> > 2. usbnet/Redfish
> > 3. i2c/MCTP/PLDM or something else?
> > 4. internal network via switch chip/Redfish or MCTP
> > I'd like to reduce our use of IPMI so I want to avoid (1).
> > ----------
> > Nancy
> Hi Nancy,
> I think it depends on whether the BMCs need to talk to each other for
> platform management, or if they manage their own hosts and we need one
> of the BMCs to broadcast out of band requests and aggregate responses.
> For the former I think PLDM over MCTP could be a good fit. This is more
> of an "inband" use-case in my opinion so I'm not sure if Redfish is well
> suited. For the latter, a Redfish based aggregation is a good option.
I think this looks like the right approach. Certainly some thought would be
required in designing the MCTP networks given the (intentionally) limited
number of endpoint IDs.
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