Draft Document for Review September 23, 2019 1:36 am 8860ch02.fm Express features also helps to reduce network latency using the SMC-R protocol in z/OS  V2.1 or later. For more information, see RFC 7609. SMC-R is transparent to applications and  can be used for LPAR-to-LPAR communications on a single CPC or for server-to-server  communications across multiple IBM Z CPCs. SMC-R uses existing IBM Z and industry standard communications technology:  Ports in the IBM Z RoCE Express features (also referred to as RNICs) are used as the  physical transport layer for RDMA. For more information about the RoCE Express features and about SMC-R, see the  IBM z15  Technical Guide , SG24-8851, and  IBM z/OS V2R2 Communications Server TCP/IP  Implementation Volume 1 , SG24-8360. Deployment of the RoCE Express features is supported in either point-to-point configuration  or switched configurations. When planning to deploy RoCE Express features in a switched  configuration, the switches must support the following requirements: IBM provides the SMC Applicability Tool (SMCAT) that helps determine the potential gains of  using SMC-R in an environment (see 2.6.5, “SMC Applicability Tool” on page 14). When preparing to deploy the RoCE Express features, consider the following items: When defining a FID in the TCP/IP profile for 10GbE RoCE Express2 or later features, the  port number is no longer applicable. GLYPH<SM590000> RDMA, which is based on queue pair (QP) technology that also uses an InfiniBand  transport service type that is called reliable connected QPs (RC-QPs), which provide  these features: – Represent SMC Links in a logical point-to-point connection. – Transport data over unique RDMA network interface cards (RNICs) that are logically  bound together to form Link Groups. Link Groups are used for high availability and load  balancing needs. GLYPH<SM590000> Single root I/O virtualization (SR-IOV) is a Peripheral Component Interconnectfi Express  (PCIe) standard that define extensions to PCIe specifications. SR-IOV enables sharing of  RoCE Express ports between LPARs in the z15. GLYPH<SM590000> Global Pause function frame (as described in the IEEE 802.3x standard) should be  enabled GLYPH<SM590000> Priority Flow Control (PFC) disabled GLYPH<SM590000> No firewalls, no routing GLYPH<SM590000> For 10GbE RoCE Express2 and later features, the port number is now configured with  the FID number in HCD (or IOCDS) and Port number  must  be configured ( there is no  default ).  GLYPH<SM590000> Port number for 10GbE RoCE Express (FC 0411) is configured in z/OS TCP/IP profile  and does not change.  GLYPH<SM590000> The RoCE Express features are “Native” PCIe features, so the following configuration  items must be provided: – Function ID – Type 24  IBM z15 (8561) Configuration Setup RoCE Express features port configuration: Planning for SMC-R configuration