Specifications

Chapter 3. Pre-installation planning 25
3.4 Switch numbering
Each FICON Director in a fabric must have a unique switch address (Domain ID) and a
unique Switch ID. This Switch ID is used in IOCDS to define the link between the FICON
channel and CU. The Switch ID can be any value between x’00” to x’FF’, while the switch
address range may be restricted by the FICON Director firmware.
The valid switch address range for a McDATA Director is between x‘61’ to x’7F’. When
defining the switch number and link addresses in the IOCP definitions, ensure that you use
values within this range.
The switch address is built for the Director by adding an offset of x’60’ to the switch Domain
ID, which is entered as a decimal value when the Director is configured.
While 0 is an invalid Domain ID, the switch ID number can range between 1 to 31. So, a total
of 31 Domain IDs is available.
This means, defining a Domain ID of 1 in the Director builds a switch address of x’61’ and a
Domain ID of 31 results in a switch address of x’7F’.
It is important to point out that some definition terms used in the IOCP and HCD are carried
over from the ESCON environment. An example of the terms used, and how they relate to the
FICON environment are shown in Figure 3-3.
Figure 3-3 Term usage with FICON Directors
򐂰 The Switch ID has to be assigned by the user, and must be unique within the scope of the
definitions (IOCP and HCD).
򐂰 The switch address is assigned by the manufacturer, and may be customized to a different
value and must be unique within the fabric.
We recommend that the Switch ID be set to the same value as the switch address of the
FICON Director, which is defined to the FICON Director at installation time. This will simplifies
the configuration and reduce confusion by having a common designation across all
definitions.
FICON
Switch
LP1-1 LP2-2 LP3-3
zSeries
Switch ID 13
Switch @ 13
Control
Unit
FICON
Switch
Switch ID 14
Switch @ 14
FICON
Channel
ISL
Switch/Director number
Switch
Switch ID
Switch #
Director
Director #
LSN (Logical Switch Number)
Switch/Director address
Switch address
Switch @
Director address
Director @
Domain ID
Domain
Fibre Channel switch address
Switch CUP Device (FICON switch)
Switch Device Number
Port @ 27
Port address
Port
Port ID
Port @
Entry switch
Cascaded switch
Link address
Control
Unit
I
O
C
P
/
H
C
D
Switch configuration