IBM DS8900F Introduction And Planning Manual page 120

The maximum distance might be greater than 10 km (6.2 miles) when a link extender provides target
initiator functions or controller emulation functions.
Note: Do not use link extenders with emulation functions on links over which Remote Mirror and Copy
operations are performed. Link extenders with emulation functions introduce more path delay.
• Because the Fibre Channel architecture allows any channel initiator to access any Fibre Channel device,
without access restrictions, a security exposure can occur. Have your technical service representative
set the Fibre Channel access modes to the correct setting. See the IBM DS8000 Host Systems
Attachment Guide for more information about Fibre Channel access modes.
• Storage systems can connect to IBM SAN Volume Controller host systems. See the IBM DS8000 Host
Systems Attachment Guide for more information.
Attention: Signal-loss tolerance for Fibre Channel links that run at 8 or 16 Gbps are reduced by
-1.4 dB as compared to links that run at 4 Gbps. Take necessary steps to ensure that links are
within the signal-loss parameters that are listed when you plan a move from 4 Gbps FC to 8 or 16
Gbps FC adapters with existing infrastructure. Using more than two patch panels or other link
connectors between two 8 or 16 Gbps ports at maximum distance of 10 km might result in greater
link loss than is acceptable. Signal loss tolerance with measurements, including all connectors and
patch panel connections, are:
• Loss per 10 km for 16 Gbps speed is -6.4 dB.
• Loss per 10 km for 8 Gbps speed is -6.4 dB.
• Loss per 10 km for 4 Gbps speed is -7.8 dB.
OM3 Fibre Channel cables are required to support 8 Gbps host adapters.
106 IBM DS8900F: DS8900F Introduction and Planning Guide