## 4.1 Introduction to I/O infrastructure 

This section describes the I/O features that are available on the IBM z14 Model ZR1 server. The z14 ZR1 servers support PCIe+ I/O drawers only. I/O cage, I/O drawer, or PCIe I/O drawer are not supported. 

Note:  Throughout this chapter, the terms adapter  and card  refer to a PCIe I/O feature that is installed in a PCIe+ I/O drawer. 

## 4.1.1 I/O infrastructure 

IBM extends the use of industry standards on the IBM Z platform by offering a Peripheral Component Interconnect Express Generation 3 (PCIe Gen3) I/O infrastructure. The PCIe I/O infrastructure that is provided by the central processor complex (CPC) improves I/O capability and flexibility, while allowing for the future integration of PCIe adapters and accelerators. 

The PCIe I/O infrastructure in z14 ZR1 consists of the following components: 

GLYPH<SM590000> PCIe fanouts that support 16 GBps I/O bus for CPC drawer connectivity to the PCIe+ I/O drawers. 

GLYPH<SM590000> PCIe fanouts that support Coupling Link Feature Integrated Coupling Adapter Short Reach (ICA SR). 

GLYPH<SM590000> The 8U, 16-slot, and 2-domain PCIe+ I/O drawer for PCIe I/O features. 

The z14 ZR1 I/O infrastructure provides the following benefits: 

GLYPH<SM590000> The bus connecting the CPC drawer to the I/O domain in the PCIe+ I/O drawer bandwidth is 16 GBps. 

GLYPH<SM590000> The PCIe+ I/O drawer also doubles the number of I/O ports compared to an I/O drawer (z13s or earlier only). Up to 32 channels (16 PCIe I/O cards) are supported in the PCIe+ I/O drawer. 

GLYPH<SM590000> Granularity for the storage area network (SAN) and the local area network (LAN): 

– The FICON Express16S+ features two channels per feature for Fibre Channel connection (FICON), High Performance FICON on Z (zHPF), and Fibre Channel Protocol (FCP) storage area networks. 

– The Open Systems Adapter (OSA)-Exp ress6S GbE and the OSA-Express6S 1000BASE-T features includes two ports each (LAN connectivity); the OSA-Express7s 25GbE and the OSA-Express6S 10 GbE features have one port each (LAN connectivity). 

GLYPH<SM590000> Native PCIe features (plugged into the PCIe+ I/O drawer): 

– IBM zHyperLink Express (new for z14 ZR1) 

– 25GbE Remote Direct Memory Access (RDMA) over Converged Ethernet (RoCE) Express2 (new) 

– 10 GbE RoCE Express2 (introduced with z14) 

– Coupling Express Long Reach (CE LR) (available on z14 M0x, z14 ZR1, z13, and z13s) 

– zEnterprise Data Compression (zEDC) Express 

– 10 GbE RDMA over RoCE Express (carry forward only) 

