3 – Planning
Multiple Chassis Fabrics
3-2 59042-00 A
3.2
Multiple Chassis Fabrics
By connecting switches together you can expand the number of available ports for
devices. Each switch in the fabric is identified by a unique domain ID, and the
fabric will automatically resolve domain ID conflicts. Because the ports are
self-configuring, you can connect SANbox2 and other FC-SW-2 compliant
switches together in a wide variety of topologies.
3.2.1
Domain ID, Principal Priority, and Domain ID Lock
The following switch configuration settings affect multiple chassis fabrics:
■Domain ID
■Principal priority
■Domain ID lock
The domain ID is a unique number from 1–239 that identifies each switch in a
fabric. The principal priority is a number (1–255) that determines the principal
switch which manages domain ID assignments for the fabric. The switch with the
highest principal priority (1 is high, 255 is low) becomes the principal switch. If the
principal priority is the same for all switches in a fabric, the switch with the lowest
WWN becomes the principal switch. The domain ID lock allows (FALSE) or
prevents (TRUE) the reassignment of the domain ID on that switch. Switches
come from the factory with the domain ID set to 1, the domain ID lock set to
FALSE, and the principal priority set to 254. Refer to the SANbox2 Switch
Management User’s Guide for information about changing the domain ID using
SANbox Manager. Refer to the ”Set Config Command” on pageB-24 for
information about changing the default domain ID domain ID lock, and principal
priority settings.
If you connect a set of SANbox2 switches then power them up together, the
principal switch will reassign any domain ID conflicts and establish the fabric. For
any switch with a domain ID conflict and a domain ID lock set to TRUE, that switch
will isolate as a separate fabric.
An unresolved domain ID conflict means that the switch with the higher WWN will
isolate as a separate fabric, and the Logged-In LEDs on both switches will flash to
show the affected ports. If you connect a new switch with its domain ID unlocked
(domain ID lock = FALSE) to an existing fabric and a domainID conflict occurs,
the new switch will isolate as a separate fabric. However, you can remedy this by
resetting the new switch or taking it offline then back online. The principal switch
will reassign the domain ID and the switch will join the fabric.