Parallel Sysplex Coupling And Server Time Protocol Connectivity - IBM z13s Technical Manual

For communications between LPARs in the same z13s server, HiperSockets eliminates the
need to use I/O subsystem features and to traverse an external network. Connection to
HiperSockets offers significant value in server consolidation by connecting many virtual
servers. It can be used instead of certain coupling link configurations in a Parallel Sysplex.
HiperSockets is extended to allow integration with IEDN, which extends the reach of the
HiperSockets network outside the CPC to the entire ensemble, and displays it as a single
Layer 2 network.
10GbE RoCE Express
The 10 Gigabit Ethernet (10GbE) RoCE Express feature is a RDMA-capable network
interface card. The 10GbE RoCE Express feature is supported on z13, z13s, zEC12, and
zBC12 servers, and is used in the PCIe I/O drawer. Each feature has one PCIe adapter. A
maximum of 16 features can be installed.
The 10GbE RoCE Express feature uses a short reach (SR) laser as the optical transceiver,
and supports the use of a multimode fiber optic cable that terminates with an LC Duplex
connector. Both a point-to-point connection and a switched connection with an
enterprise-class 10 GbE switch are supported.
Support is provided by z/OS, which supports one port per feature, dedicated to one partition
in zEC12 and zBC12. With z13s servers, both ports, shared by up to 31 partitions, are
supported.
For more information, see Appendix D, "Shared Memory Communications" on page 475.
Shared Memory Communications - Direct Memory Access
In addition to supporting SMC-R, z13s support is a new protocol called SMC-D over ISM.
Unlike SMC-R, SMC-D has no dependency on the RoCE Express feature. SMC-D provides
low latency communications within a CPC by using shared memory.
SMC-R, by using RDMA, can vastly improve the transaction, throughput, and CPU
consumption rates for unchanged TCP/IP applications. Direct memory access (DMA) can
provide comparable benefits on an internal LAN.
z Systems now supports a new ISM virtual PCIe (vPCIe) device to enable optimized
cross-LPAR TCP communications using SMC-D. SMC-D maintains the socket-API
transparency aspect of SMC-R so that applications that use TCP/IP communications can
benefit immediately without requiring any application software or IP topology changes. For
more information, see D.3, "Shared Memory Communications - Direct Memory Access" on
page 489.
Note: SMC-D does not support Coupling facilities or access to the IEDN network. In
addition, SMC protocols do not currently support multiple IP subnets.

1.3.7 Parallel Sysplex Coupling and Server Time Protocol connectivity

Support for Parallel Sysplex includes the Coupling Facility Control Code and coupling links.
Coupling links support
The z13s CPC drawer supports up to 8 PCIe Gen3 fanouts and up to four IFB fanouts for
Parallel Sysplex coupling links. A z13s Model N20 with optional second CPC drawer supports
a total of 16 PCIe Gen3 fanouts and 8 IFB fanout slots (four per CPC drawer). Coupling
20
IBM z13s Technical Guide