## Coupling links support 

Coupling connectivity in support of Parallel Sysplex environments is provided on the z14 server by the following features: 

GLYPH<SM590000> Internal Coupling (IC) links that are operating at memory speed. 

GLYPH<SM590000> Integrated Coupling Adapter Short Reach 

GLYPH<SM590000> Coupling Express Long Reach 

GLYPH<SM590000> IFB coupling links: 

– HCA3-O, 12x Parallel SysplexInfiniBand (IFB) coupling links. 

– HCA3-O, 1x Parallel Sysplex In finiBand (IFB) coupling links. 

Note $^{a}$: z14 is the last high-end IBM Z server to support Parallel Sysplex InfiniBand (PSIFB) coupling links; z13s is the last midrange IBM Z server to support them. IBM Z enterprises should plan to migrate off from PSIFB links. 

a. All statements regarding IBM plans, directions, and intent are subject to change or withdrawal without notice. Any reliance on these statements of general direction is at the relying party’s sole risk and will not create liability or obligation for IBM. 

All coupling link types can be used to carry STP messages. 

## Integrated Coupling Adapter Short Reach 

The Integrated Coupling Adapter Short Reach (ICA SR) feature (introduced with IBM z13) is a two-port fanout that is used for short distance coupling connectivity. It uses PCIe Gen3 technology, with x16 lanes that are bifurcated into x8 lanes for coupling. 

The ICA SR is designed to drive distances up to 150 m and support a link data rate of 8 GBps. The ICA SR fanout takes one PCIe I/O fanout slot in the z14 CPC drawer. It is used for coupling connectivity between z14, z13, and z13s CPCs, and cannot be connected to HCA3-O or HCA3-O LR coupling fanouts. The ICA SR is compatible with another ICA SR only. 

## Coupling Express Long Reach 

z14 introduces the new Coupling Express Long Range (CE LR), which is a two-port feature that is used for long-distance coupling connectivity and defined as coupling channel type, CL5. Unlike the 1x IFB InfiniBand coupling links, which were plugged into the CPC drawer, the CE LR link is plugged in a PCIe I/O drawer slot, which uses industry standard I/O technology. 

Compared to the HCAO-3 LR feature, which has 4-port and 4-link increments, the CE LR link allows for more granularity when scaling up or completing maintenance. Link performance is similar to the InfiniBand 1x coupling link and uses identical Single Mode fiber. The CE LR link provides point-to-point coupling connectivity at distances of 10 km unrepeated and 100 km with a qualified dense wavelength division multiplexing (DWDM) device. 

## IFB coupling links 

The following Parallel Sysplex coupling links use IFB: 

GLYPH<SM590000> 12x InfiniBand coupling links (HCA3-O) are used for local connections up to 150 meters (492 feet). The 12x IFB link (HCA3-O) connects between z14, z13, z13s, zEC12, and zBC12 servers. It cannot be connected to an ICA SR. 

GLYPH<SM590000> 1x InfiniBand coupling links (HCA3-O LR) are used for extended distance connections between z14, z13, z13s, zEC12, and zBC12 servers. The HCA3-O LR 1X InfiniBand links have a bandwidth of 5 Gbps, use single mode fiber, and cannot be connected to a CE LR. 

