a. Minimum fiber bandwidths in MHz/km for multimode fiber optic links are included in parentheses, where  applicable. b. With OSA-Express5S, the only link rate supported is 1000 Mbps. 25GbE RoCE Express2.1 (FC 0450) is installed in the PCIe+ I/O drawer and is supported  only on IBM z15 servers. The 25GbE RoCE Express2.1 is a native PCIe feature. It does not  use a CHPID and is defined by using the IOCP  FUNCTION  statement or in the hardware  configuration definition (HCD). Switch configuration for RoCE Express2.1:  If the IBM 25GbE RoCE Express2.1  features are connected to 25GbE switches, the switches must meet the following  requirements: The 25GbE RoCE Express2.1 feature does not support auto-negotiation to any other  speed and runs in full duplex mode only.  10GbE and 25GbE RoCE features should not be mixed in a z/OS SMC-R Link Group.  Mixing same speed RoCE features in the same z/OS SMC-R link group is allowed. The maximum supported unrepeated distance, point-to-point, is 100 meters (328 feet). A  client-supplied cable is required. Two types of cables can be used for connecting the port to  the selected 25GbE switch or to the 25GbE RoCE Express2.1 feature on the attached server: On IBM z15 servers, both ports are supported by z/OS and can be shared by up to 126  partitions (LPARs) per PCHID. The 25GbE RoCE Express2.1 feature uses SR optics and  supports the use of a multimode fiber optic cable that ends with an LC Duplex connector. Both  point-to-point connections and switched connections with an enterprise-class 25GbE switch  are supported. GLYPH<SM590000> Global Pause function enabled GLYPH<SM590000> Priority flow control (PFC) disabled GLYPH<SM590000> No firewalls, no routing, and no IEDN GLYPH<SM590000> OM3 50-micron multimode fiber optic cable that is rated at 2000 MHz-km that ends with an  LC Duplex connector, which supports 70 meters (229 feet) GLYPH<SM590000> OM4 50-micron multimode fiber optic cable that is rated at 4700 MHz-km that ends with an  LC Duplex connector, which supports 100 meters (328 feet) 190  IBM z15 (8561) Technical Guide 25GbE RoCE Express2.1 OSA-Express5S 10GbE LR 0415 10 SM 9 µm 10 km (6.8 miles) OSA-Express5S 10GbE SR 0416 10 MM 62.5 µm MM 50 µm 33 m (200) 82 m (500) 300 m (2000) OSA-Express5S GbE LX 0413 1.25 SM 9 µm 5 km (3.1 miles) OSA-Express5S GbE SX 0414 1.25 MM 62.5 µm MM 50 µm 275 m (200) 550 m (500) OSA-Express5S 1000BASE-T b 0417 100 or 1000 Mbps Cat 5, Cat 6 unshielded twisted  pair (UTP) 100 m Channel feature Feature  code Bit rate in Gbps Cable type Maximum unrepeated  distance$^{a}$ (MHz - km)