96257 Sun Confidential: Internal Only B-75
Revision A
B
FICON Channel Extension
Guidelines
This appendix provides information about FICON channel extensions for the VSM system.
Content includes:
• “Definition of Terms” on page B-76
• “General Channel Extension Considerations”, including:
- “Understand Channel Extension Performance Limitations” on page B-77
- “Channel Extenders Are Invisible to Other Devices” on page B-77
- “Channel Extenders Can Cause Timing Problems” on page B-77
- “Channel Extenders Can Insert Fake I/O Errors” on page B-77
- “Avoid RECLAIMs and DRAINs on Channel-Extended RTDs” on page B-77
- “Avoid RECALLs on Channel-Extended RTDs” on page B-77
- “Avoid Syncsort Apps That Use Long Chains on Channel-Extended VTDs” on page B-
77
• “FICON Topologies” on page B-78
• “Placement of Extension Equipment” on page B-78
• “Interoperability Testing” on page B-78
• “FICON Channel Extension – Sample Configurations” on page B-79
• “McData/CNT Channel Extension Interoperability”, including:
- “Set Buffer-to-Buffer Credits at Director Ports” on page B-81
- “Set Extension-Attached Director Ports to Fixed Speeds” on page B-81
- “Set Extension Ports to Fixed Speeds When Extending a VTSS-to-VTSS Channel Link
(CLINK) or a VTSS-to-RTD Link” on page B-82
- “ISL Failover Is Supported Only in Shuttle Mode” on page B-82
- “Avoiding Host Protocol Timeouts” on page B-82
- “Performance Considerations” on page B-82
• “Cisco Systems Channel Extension Interoperability” on page B-83.
Note: Always consult your selected vendor’s release documentation for their extension
products, and guidelines for proper application of those products.
