HP Mainframe Connectivity Design Guide

NOTE: The minimum number of BB_credits listed in Table 84 (page 135) is based on transmitting
full FC frames with a data payload of 2,112 bytes. Many mainframe applications do not use full
FC frames, and therefore, require more BB_credits than are listed to maintain performance. For
more information, contact an HP storage representative.
B-series directors
Table 85 (page 136) lists the B-series FICON director extended fabric settings for maintaining
performance with extended fabric ISLs.
Table 85 B-series FICON director extended fabric settings
SettingExtended fabric item
1 Gb/s, 2 Gb/s, 4 Gb/s, 8 Gb/s, 10 Gb/s, and 16 Gb/sSupported ISL port speeds
1 hopMaximum number of hops
300 kmMaximum ISL distance
This setting is application dependent.
BB_credits
For information about setting BB_credits, see HP StorageWorks Fabric OS Administrator
Guide, available at http://h20000.www2.hp.com/bizsupport/TechSupport/
DocumentIndex.jsp?contentType=SupportManual&lang=en&cc=us&docIndexId=179111&
taskId=101&prodTypeId=12169&prodSeriesId=1143936.
An Extended Fabric license is required for distance selections other than L0 and LE. The
B-series FICON directors can configure additional BB_credits based on the extended fabric
ISL mode or the distance configured for the port.
When using B-series FICON directors with extended fabric ISLs, consider the following:
• An extended fabric license is required for B-series switches when extending a fabric beyond
10 km.
• Select the ISL mode based on the WDM architecture. See Table 83 (page 133).
For active protocol handling, use portCfgISLMode slot/port, 1.◦
◦ For passive protocol handling, use portCfgISLMode slot/port, 0.
CAUTION: Do not enable portCfgISLMode and portCfgLongDistance L0.5, L1, or L2
mode at the same time. Doing so causes fabric segmentation to occur. However, you can enable
portCfgISLMode and portCfgLongDistance LE, LD, or LS mode at the same time.
B-series trunking considerations follow:
• An ISL trunking license is required.
• Trunking is supported at 2 Gb/s, 4 Gb/s, 8 Gb/s, or 16 Gb/s (1 Gb/s and 10 Gb/s are
not supported).
• Trunking deskew timers can accommodate a maximum difference of 400 m (deskew value of
200) between the shortest and longest ISLs in a trunk.
• For optimal performance, HP recommends a maximum ISL length difference of 30 m.
• Trunking is not supported with ports configured for portCfgISLMode slot/port, 1 (R_RDY mode).
For information about trunking distance rules, see HP StorageWorks Fabric OS Administrator
Guide.
C-series directors
Table 86 (page 137) lists the C-series FICON director extended fabric settings for maintaining
performance with extended fabric ISLs.
136 FICON and FICON SAN extension