FICON Administrator's Guide v6.4.0 (53-1001771-01, June 2010)

24 FICON Administrator’s Guide
53-1001771-01
Control Unit Port (CUP) overview
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FIGURE 9 FICON CUP
Figure 9 is a simplified representation of a FICON environment and how CUP fits into that
environment. FICON directors have the embedded port “FE” for the CUP port. On FICON directors
that have 256 or more ports, this has caused a slight dilemma. This logical “FE” overlaps the
physical “FE” port, so the physical “FE” and “FF” ports cannot be used on these directors for FICON
connectivity. They may still be used for port swaps or for a FICON/FCP intermix, however, they
cannot be generated in HCD for FICON connectivity. In a FICON environment, only one RMF LPAR
should attempt to access the CUP port at any one time, and it is still best practice to have two or
more CHPIDs with access to the CUP. However, too much activity to the FICON CUP can cause
missing interrupts, leading to the potential for having a boxed device.
FICON CUP restrictions
The following restrictions apply to Brocade FICON directors having at least 256 ports when FMS
mode is enabled and CUP protocol is used to manage the switch:
• FICON Management Server mode (FMS mode) must be enabled on the switch to enable CUP
management features. When this mode is enabled, Fabric OS prevents local switch commands
from interfering with host-based management commands by initiating serialized access to
switch parameters.
ATTENTION
Once FMS mode is enabled, do not bind FE/FF to any ports using either the portAddress or
wwnAddress commands.
• The switch is advertised to the mainframe by CUP as a 256-port switch (due to CUP protocol
limitation).