Guidelines for Using SMB Direct support on Windows 2019 using RDMA over converged Ethernet (RoCE) v2
General Guidelines and Limitations:
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Cisco UCS Manager release 4.1.x and later releases support Microsoft SMB Direct with RoCEv2 on Microsoft Windows Server 2019. Cisco recommends that you have all KB updates from Microsoft for your Windows Server 2019.
Note
RoCEv2 is not supported on Microsoft Windows Server 2016.
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Cisco recommends you check UCS Hardware and Software Compatibility specific to your UCS Manager release to determine support for Microsoft SMB Direct with RoCEv2 on Microsoft Windows 2019.
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Microsoft SMB Direct with RoCEv2 is supported only with fourth generation Cisco UCS VIC 1400 Series adapters. It is not supported with UCS VIC 12xx Series and 13xx Series adapters. SMB Direct with RoCEv2 is supported on all UCS Fabric Interconnects.
Note
RoCE v1 is not supported with any fourth generation Cisco UCS VIC 1400 Series adapters.
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RoCEv2 configuration is supported only between Cisco adapters. Interoperability between Cisco adapters and third party adapters is not supported.
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RoCEv2 supports two RoCEv2 enabled vNIC per adapter and four virtual ports per adapter interface, independent of SET switch configuration.
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RoCEv2 cannot be used on the same vNIC interface as NVGRE, NetFlow, and VMQ features.
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RoCEv2 cannot be used with usNIC.
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RoCEv2-enabled vNIC interfaces must have the no-drop QoS system class enabled in UCS Manager.
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The RoCE Properties queue pairs setting must for be a minimum of 4 queue pairs.
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Maximum number of queue pairs per adapter is 2048.
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The QoS No Drop class configuration must be properly configured on upstream switches such as Cisco Nexus 9000 series switches. QoS configurations will vary between different upstream switches
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The maximum number of memory regions per rNIC interface is 131072.
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UCS Manager does not support fabric failover for vNICs with RoCEv2 enabled.
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SMB Direct with RoCEv2 is supported on both IPv4 and IPv6.
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RoCEv2 cannot be used with GENEVE offload.
MTU Properties:
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In older versions of the VIC driver, the MTU was derived from either a UCS Manager service profile or from the Cisco IMC vNIC MTU setting in standalone mode. This behavior changed for 4th generation VIC 1400 Series adapters, where MTU is controlled from the Windows OS Jumbo Packet advanced property. A value configured from UCS Manager or Cisco IMC has no effect.
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The RoCEv2 MTU value is always power-of-two and its maximum limit is 4096.
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RoCEv2 MTU is derived from the Ethernet MTU.
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RoCEv2 MTU is the highest power-of-two that is less than the Ethernet MTU. For example:
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if the Ethernet value is 1500, then the RoCEv2 MTU value is 1024
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if the Ethernet value is 4096, then the RoCEv2 MTU value is 4096
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if the Ethernet value is 9000, then the RoCEv2 MTU value is 4096
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Windows NDPKI Modes of Operation:
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Cisco's implementation of Network Direct Kernel Provider Interface (NDPKI) supports two modes of operation: Mode 1 and Mode 2. Modes 1 and 2 relate to the implementation of Network Direct Kernel Provider Interface (NDKPI): Mode 1 is native RDMA, and Mode 2 involves configuration for the virtual port with RDMA. Cisco does not support NDPKI Mode 3 operation.
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The recommended default adapter policy for RoCEv2 Mode1 is Win-HPN-SMBd .
The recommended default adapter policy for RoCEv2 Mode2 is MQ-SMBd.
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RoCEv2 enabled vNICs for Mode2 operation require the QoS host control policy set to full.
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Mode 2 is inclusive of Mode 1: Mode 1 must be enabled to operate Mode 2.
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On Windows. the RoCEv2 interface supports MSI & MSIx interrupt modes. By default, it is in MSIx interrupt mode. Cisco recommends you avoid changing interrupt mode when the interface is configured with RoCEv2 properties.
Downgrade Limitations:
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Cisco recommends you remove the RoCEv2 configuration before downgrading to any non-supported RoCEv2 release. If the configuration is not removed or disabled, downgrade will fail.