SNIA-SDC23-Jurski-Loewen-Constantine-Orozco-Overcoming-SMBus-limitations-with-I3C.pdf

1、1|2023 SNIA.All Rights Reserved.Virtual ConferenceSeptember 28-29,2021Overcoming SMBus Limitations with I3CPresented by:Janusz Jurski(Intel),Myron Loewen(Solidigm),Anthony Constantine(Intel),Juan Orozco(Intel)Bryan Kelly(Microsoft),Zbigniew Lukwinski(Intel)Co-authors:2|2023 SNIA.All Rights Reserved.

2、AgendaSMBus LimitationsI3C-based SolutionExperimentationSummary&Call to Action3|2023 Storage Developer Conference.Intel,Solidigm,Microsoft.All Rights Reserved.SMBus Limitations4|2023 SNIA.All Rights Reserved.SMBus/I2C Sideband Management Overview SMBus/I2C sideband interface used by all PCIe/CXL for

3、m factors,incl.storage No common I2C/SMBus addressing architecture ARP expected by CEM Spec but often not implemented(ARP optional in SMBus spec)system vendors maintain address databases to avoid collisions vendor-dependent proprietary solutions used instead,typically involving I2C/SMBus MUX Securit

4、y expectations drive MUX-based architectures prevents peer-to-peer communications Legacy use cases simple communication driven by only BMC with quick responses by endpoints(FRU read,temp sensor,etc.)low bandwidth sufficient(typically 100kHz)BMCMUXEndpoint 2Endpoint 1Endpoint 3SMBusSMBus5|2023 SNIA.A

5、ll Rights Reserved.MCTP over SMBus w/MUX&Advanced Use Cases Dont Work MCTP over SMBus expects continuous SMBus expectation not valid in systems with MUX SMBus arbitration does not work over MUX-based I2C/SMBus Endpoints try to transmit when MUX switched away eollowing the specifications,due to no AC

6、K,they retry and drop packets after a couple of milliseconds MCTP over SMBus with MUX generally unusable for:long-running tasks(SPDM,etc.)asynchronous communication(alerts,events,notifications,etc.)streaming from endpoint(telemetry,etc.)large MCTP messages fragmented into many MCTP packets(frequent