IBM Z9, Planning Manual

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CHPID PATH=30,SHARED
CNTLUNIT CUNUMBR=10,PATH=30,CUADD=0
IODEVICE ADDRESS=VVVV,CUNUMBR=10,PART=LP1
CNTLUNIT CUNUMBR=11,PATH=30,CUADD=1
IODEVICE ADDRESS=WWWW,CUNUMBR=11,PART=LP2
CNTLUNIT CUNUMBR=12,PATH=30,CUADD=2
IODEVICE ADDRESS=XXXX,CUNUMBR=12,PART=LP3
CNTLUNIT CUNUMBR=13,PATH=30,CUADD=3
IODEVICE ADDRESS=YYYY,CUNUMBR=13,PART=LP4
CNTLUNIT CUNUMBR=14,PATH=30,CUADD=4
IODEVICE ADDRESS=ZZZZ,CUNUMBR=14,PART=LP5
Using a Director to Block Ports or Prohibit Dynamic Connections or
Communication: When ESCON or FICON Directors are used in an I/O
configuration, you can prevent channels from establishing logical paths or can
remove established logical paths by either blocking a Director port or by prohibiting
a dynamic connection or communication between two Director ports.
In terms of logical path removal, blocking a Director port connected to a channel
produces a similar outcome to configuring offline a channel or all channel images of
a shared channel. Blocking a Director port connected to a control unit prevents any
logical path from being established to the attached control unit port.
You can more selectively prevent logical paths from being established by prohibiting
a dynamic connection between two ESCON Director ports or dynamic
communication between two FICON Director ports instead of blocking a Director
port. By prohibiting a dynamic connection or communication between two Director
ports, you can control which channels have connectivity to a control unit port rather
than blocking all connectivity to the control unit port.
Prohibiting a dynamic connection or communication between two Director ports
affects all channel images of a shared channel. The system will not establish any
logical paths to the attached control unit port from any of the LPs that share the
ESCON or FICON channel.
You can prohibit dynamic connections or communication between Director ports by
modifying the active configuration table. The active configuration table specifies the
connectivity status of a port relative to the other ports on the Director. When a
Director is first installed, it has a default configuration that allows any-to-any
connectivity (every port can dynamically connect or communicate with every other
port). If you require a different configuration than this, you can define and designate
a different table to be the default configuration used at power-on of the Director.
This table will allow only those dynamic connections or communication necessary to
establish the logical paths the configuration requires. Dynamic connections or
communication necessary to establish other logical paths (for example, those
necessary for backup configurations) would be prohibited by the default
configuration of the Director.
Figure 2-7 on page 2-20 shows an example of prohibiting dynamic connections.
CPC1, CPC2, CPC3, and CPC4 are all production systems and CPC5 is a backup
system to be used only if one of the other CPCs fail. If the default configuration
used by the ESCON Director (ESCD) prohibits all dynamic connections between
CPC5 and the 3990, the 3990 will only be requested to establish a total of 16
logical paths from the channels on CPC1, CPC2, CPC3, and CPC4. If one of four
Chapter 2. Planning Considerations
2-19