## Coupling links support 

Integrated Coupling Adapter (ICA) Short Reach and Coupling Express Long Reach (CE LR) coupling link options provide high-speed connectivity at short and longer distances over fiber optic interconnections. Several areas of this book address CE LR and ICA SR characteristics and support. For more information, see 4.6.4, “Parallel Sysplex connectivity” on page 153. 

## Integrated Coupling Adapter 

PCIe Gen3 fanout, which is also known as Integrated Coupling Adapter Short Range (ICA SR), supports a maximum distance of 150 meters (492 feet) and is defined as CHPID type CS5 in IOCP. 

## Coupling Express Long Reach 

The Coupling Express Long Reach (CE LR) link provides point-to-point coupling connectivity at distances of 10 kilometers (6.21 miles) unrepeated and defined as CHPID type CL5 in IOCP. The supported operating systems are listed in Table 7-5 on page 217. 

Note:  IBM z14 ZR1 server does not  support HCA3-O fanout for 12x IFB (FC 0171) and HCA3-O LR fanout for 1x IFB (FC 0170).$^{a}$ As announced previously, z14 Model M0x is the last IBM Z server to support these adapters. 

Enterprises should migrate from HCA3-O and HCA3-O LR adapters to ICA SR or Coupling Express Long Reach (CE LR) adapters on z14 ZR1, z14 M0x, z13, and z13s. For high-speed short-range coupling connectivity, enterprises should migrate to the Integrated Coupling Adapter (ICA SR). 

For long-range coupling connectivity, enterprises should migrate to the new Coupling Express LR coupling adapter. For long-range coupling connectivity that requires a DWDM, enterprises must determine their needed DWDM vendor’s plan to qualify the planned replacement long-range coupling links. 

IBM Z enterprises should plan to migrate from InfiniBand coupling links. For high-speed short-range coupling connectivity, enterprises should migrate to the Integrated Coupling Adapter (ICA SR). 

For long-range coupling connectivity, enterprises should migrate to the new CE LR coupling link. For long-range coupling connectivity that requires a DWDM, enterprises must determine their wanted DWDM vendor’s plan to qualify the CE LR. For more information, see Hardware Announcement 117-031, dated March 2017. 

a. Per previous Statement of Direction. 

## Virtual Flash Memory use by CFCC 

VFM can be used in coupling facility images to provide extended capacity and availability for workloads that use WebSphere MQ Shared Queues structures. The use of VFM can help availability by reducing latency from paging delays that can occur at the start of the workday or during other transitional periods. It is also designed to help eliminate delays that can occur when diagnostic data during failures are collected. 

## CFCC Coupling Thin Interrupts 

The Coupling Thin Interrupts enhancement is delivered with CFCC 19. It improves the performance of a CF partition and improves the dispatching of z/OS LPARs that are awaiting the arrival of returned asynchronous CF requests when used in a shared engine environment. For more information, see “ Coupling Thin Interrupts ” on page 86. The supported operating systems are listed in Table 7-5 on page 217. 

