Brocade FICON Administrator's Guide v7.1.0 (53-1002753-01, March 2013)

FICON Administrator’s Guide 27
53-1002753-01
Addressing modes
2
• If addresses 0xFE or 0XFF have been assigned to physical ports, those ports must be disabled
before FMS can be enabled.
• For FICON CUP, FMS mode is enabled on the logical switch and not the chassis. For example, in
a Virtual Fabrics environment on the Brocade 6510 switch and the Brocade DCX 8510-4 and
DCX 8510-8 Backbones, you must set FMS mode independently on each logical switch. FMS
mode is currently limited to four logical switches per chassis.
• Each logical switch has its own configuration data, such as the initial program load (IPL) file,
configuration data elements (PDCM, PIB, port address names, mode register, key counter),
and CUP configuration files.
Addressing modes
There are three 256-area addressing modes that provide extended functionality in dynamically
created partitions:
• Mode 0 or 10-bit addressing.
• Mode 1 or zero-based addressing.
• Mode 2 or port-based addressing.
Mode 0 (10-bit addressing)
This mode is called “Disabled” in the Brocade Network Advisor. It is not Supported For FICON, but
can be used for mainframe FCP channels associated with zLinux or zVM partitions.
Mode 0 uses the two upper bits in the ALPA to address up to 1024 ports in a single logical switch.
Since a 64-port blade is the highest port count blade available and eight slots is the highest slot
count available in a Brocade chassis, the practical address limit is 512 ports. Since NPIV also uses
these bits, this address mode leaves just 6 bits for NPIV. Therefore, the maximum NPIV logins is
limited to 64 (63 practical), not 256.
Mode 1 (zero-based addressing)
This is the recommended mode for FICON. In this addressing mode, port numbers are assigned
starting with 00 as the ports are moved into the logical switch. Typically, several ports are moved at
once, resulting in a port address assignment starting with 00 for the bottom port in the left-most
port column on the blade in the lowest slot number. Starting from port 00, addresses increment by
one as ports progress up the blade and to the bottom port of the right port column. Numbers then
increment to the top port of the column, and then on to the next blade. This is different than how
port addresses are assigned in a chassis that is not enabled for virtual fabrics.
The ALPA is always 0x00. Therefore zero-based addressing limits the maximum switch size to 256
ports. Since zero-based addressing does not use any of the ALPA bits and may be preferred for
native FCP with zVM to allow up to 256 (255 practical) NPIV logins.