Technical data

Fabric OS Administrator’s Guide A-1
Publication Number: 53-0000518-09
Appendix
A
Configuring the PID Format
Port identifiers (called PIDs) are used by the routing and zoning services in Fibre Channel fabrics to
identify ports in the network. All devices in a fabric must use the same PID format, so when you add
new equipment to your SAN, you might need to change the PID format on legacy equipment.
About PIDs and PID Binding
The PID is a 24-bit address built from three 8-bit fields:
• domain
• area_ID
• AL_PA
Many scenarios cause a device to receive a new PID; for example, unplugging the device from one port
and plugging it into a different port as part of fabric maintenance, or changing the domain ID of a
switch, which might be necessary when merging fabrics, or changing compatibility mode settings.
Some device drivers use the PID to map logical disk drives to physical Fibre Channel counterparts.
Most drivers can either change PID mappings dynamically (called dynamic PID binding) or use the
WWN of the Fibre Channel disk for mapping (called WWN binding).
Some older device drivers behave as if a PID uniquely identifies a device (they use static PID binding).
These device drivers should be updated, if possible, to use WWN or dynamic PID binding instead,
because static PID binding creates problems in many routine maintenance scenarios. Fortunately, very
few device drivers still behave this way. Many current device drivers enable you to select static PID
binding as well as WWN binding. You should only select static binding if there is a compelling reason,
and only after you have evaluated the impact of doing so.
Summary of PID Formats
SilkWorm switches employ these types of PID formats:
• VC encoded
This is the format defined by the SilkWorm 1000 series. Connections to these switches are not
supported in Fabric OS v4.0.0 and later.
• native
Introduced with the SilkWorm 2000 series, this format supports up to 16 ports per switch.