Zoning; Multi-Switch Fabrics - HP StorageWorks Director 2/140 Installation Manual

Zoning

The director supports a name server zoning feature that partitions attached devices into
restricted-access groups called zones. Devices in the same zone can recognize and communicate
with each other through switched port-to-port connections. Devices in separate zones cannot
communicate with each other.
Zoning is configured by authorizing or restricting access to name server information associated with
device N_Ports that attach to director fabric ports (F_Ports). A zone member is specified by the port
number to which a device is attached, or by the eight-byte (16-digit) World Wide Name (WWN)
assigned to the host bus adapter (HBA) or Fibre Channel interface installed in a device. A device
can belong to multiple zones.
CAUTION: If zoning is implemented by port number, a change to the director fiber-optic cable
configuration disrupts zone operation and may incorrectly include or exclude a device from a zone.
If zoning is implemented by WWN, removal and replacement of a device HBA or Fibre Channel
interface (thereby changing the device WWN) disrupts zone operation and may incorrectly include
or exclude a device from a zone.
In Open Fabric mode, only zoning by WWN is supported. Zoning by port numbers is not
supported.
Zones are grouped into zone sets. A zone set is a group of zones that is enabled (activated) or
disabled across all directors and edge switches in a multi-switch fabric. Only one zone set can be
enabled at one time.

Multi-switch fabrics

A Fibre Channel topology that consists of one or more interconnected directors or switch elements is
called a fabric. Operational software provides the ability to interconnect directors (through
expansion port (E_Port) connections) to form a multi-switch fabric. The data transmission path
through the fabric is typically determined by fabric elements and is user-transparent. Subject to
zoning restrictions, devices attached to any interconnected director can communicate with each
other through the fabric.
Because a multi-switch fabric is typically complex, maintenance personnel should be aware that
several factors can degrade fabric performance or cause connectivity failures. These factors include:
• Domain ID assignment—Each director in a fabric is identified by a unique domain ID that
ranges from 1 through 31. A domain ID of 0 is invalid. If two operational fabrics join, they
determine if any domain ID conflicts exist between the fabrics. If one or more conflicts exist, the
E_Ports that form the interswitch link (ISL) segment to prevent the fabrics from joining.
• Zoning—In a multi-switch fabric is configured on a fabric-wide basis, and a change to the
zoning configuration is applied to all directors and switch elements in the fabric. To ensure
zoning is consistent across a fabric, the following rules are enforced when two fabrics (zoned or
unzoned) join:
16 Overview