Shared Memory Communications over Remote Direct Memory Access

z/OS® V2R1 Communications Server provides significant performance improvements for TCP protocol workloads on external networks. This solution uses Shared Memory Communications over Remote Direct Memory Access (SMC-R) for TCP connections to remote peers on external networks that also support this function.

Restrictions:

This function does not support external networks that contain a mix of interfaces, where some interfaces specify a VLAN ID and some interfaces do not specify a VLAN ID.

Incompatibilities: This function does not support IPAQENET interfaces that are defined by using the DEVICE, LINK, and HOME statements. Convert your IPAQENET definitions to use the INTERFACE statement to enable this support.

Dependencies:

This function requires the IBM® zEnterprise® EC12 (zEC12) with driver 15, the IBM zEnterprise BC12 (zBC12), or later.
This function requires at least one IBM 10GbE RoCE Express® feature that is configured in the hardware configuration definition (HCD) with a Peripheral Component Interconnect Express (PCIe) function ID (PFID).

Using Shared Memory Communications over Remote Direct Memory Access

To use Shared Memory Communications over Remote Direct Memory Access, perform the appropriate tasks in Table 1.

Table 1. Shared Memory Communications over Remote Direct Memory Access
Task	Reference
If you are using IPv4 QDIO interfaces that are defined with the DEVICE, LINK, and HOME statements, convert those definitions to use the IPAQENET INTERFACE statement.	Steps for converting from IPv4 IPAQENET DEVICE, LINK, and HOME definitions to the IPv4 IPAQENET INTERFACE statement in z/OS Communications Server: IP Configuration Guide
Configure at least one 10GbE RoCE Express feature in HCD.	z/OS Hardware Configuration Definition (HCD) Reference Summary
Select a unique physical network (PNet) ID for each of the networks. Configure the appropriate PNet ID in HCD for each OSD CHPID on a network and configure the PNet ID on each 10GbE RoCE Express interface to be used on that network	z/OS Hardware Configuration Definition (HCD) Reference Summary
Configure SMCR on the GLOBALCONFIG statement in the TCP/IP profile, and specify the PFID and optionally the port number corresponding to each 10GbE RoCE Express interface.	GLOBALCONFIG statement in z/OS Communications Server: IP Configuration Reference
For each IPv4 interface to be used for SMC-R, configure a nonzero subnet mask on the INTERFACE statement in the TCP/IP profile and use the same subnet value as the remote peer stack. For each IPv6 interface to be used for SMC-R, ensure that the interface has at least one associated prefix in common with the remote peer stack.	Shared Memory Communications over Remote Direct Memory Access in z/OS Communications Server: IP Configuration Guide
Optionally, restrict SMC-R from being used by certain server applications by coding the NOSMCR option on the PORT or PORTRANGE statement that defines the server port.	PORT statement and PORTRANGE statement in z/OS Communications Server: IP Configuration Reference
Display whether the stack is enabled for SMC-R by issuing the Netstat CONFIG/-f command.	Netstat: CONFIG/-f report in z/OS Communications Server: IP System Administrator's Commands
Display the status of the 10GbE RoCE Express feature by issuing the D PCIE command.	D PCIE command in z/OS MVS System Commands
Display information about the dynamic 10GbE RoCE Express TRLEs by issuing the D NET,ID=`trle`, or D NET,TRL,TRLE=`trle` command.	DISPLAY ID command and c in z/OS Communications Server: SNA Operation
Display information about a 10GbE RoCE Express interface by issuing the Netstat DEvlinks/-d command for the 10GbE RoCE Express interface.	Netstat DEvlinks/-d report in z/OS Communications Server: IP System Administrator's Commands
Display the PNet ID for an active OSD or 10GbE RoCE Express interface using the Netstat DEvlinks/-d command or by issuing the D NET,ID=`trle` or D NET,TRL,TRLE=`trle` command.	See the following topics: DISPLAY ID command and DISPLAY TRL command in z/OS Communications Server: SNA Operation Netstat DEvlinks/-d report in z/OS Communications Server: IP System Administrator's Commands
Display information about the number of sends, receives, and bytes that went over a 10GbE RoCE Express interface by issuing the Netstat DEvlinks/-d command for the 10GbE RoCE Express interface or by using VTAM® tuning statistics for the 10GbE RoCE Express interface.	See the following topics: Netstat DEvlinks/-d report in z/OS Communications Server: IP System Administrator's Commands MODIFY TNSTAT command in z/OS Communications Server: SNA Operation
Display how many TCP connections are using SMC-R by issuing the Netstat STATS/-S command.	Netstat STATS/-S report in z/OS Communications Server: IP System Administrator's Commands
Display information about which TCP connections are using SMC-R by issuing the Netstat ALL/-A command.	Netstat ALL/-A report in z/OS Communications Server: IP System Administrator's Commands
Display information about storage that is being used by TCP/IP for SMC-R by issuing the D TCPIP,,STOR command.	D TCPIP,,STOR command in z/OS Communications Server: IP System Administrator's Commands
Display information about SMC-R link groups and the associated SMC-R links by issuing the Netstat DEvlinks/-d command with the SMC parameter. Use this information to verify the redundancy level of each SMC-R link group.	Netstat DEvlinks/-d report in z/OS Communications Server: IP System Administrator's Commands