FW 05.01.00 and SW 07.01.00 HP StorageWorks SAN High Availability Planning Guide (AA-RS2DC-TE, June 2003)

Planning Considerations for Fibre Channel Topologies
79SAN High Availability Planning Guide
Fabric elements cooperate to receive data from the N_Port of an attached device,
route the data through the proper director or switch fabric ports (F_Ports), and
deliver the data to the N_Port of a destination device. The data transmission path
through the fabric is typically determined by the fabric elements and is transparent
to the user. Subject to zoning restrictions, devices attached to any of the
interconnected directors or switches can communicate with each other through the
fabric.
A multi-switch fabric is typically complex and provides the facilities to maintain
routing to all device N_Ports attached to the fabric, handle flow control, and
satisfy the requirements of the classes of Fibre Channel service that are supported.
Fabric Topology Limits
Operation of multiple directors or switches in a fabric topology is subject to the
following topology limits. Consider the impact of these limits when planning the
fabric.
■ Fabric Elements — Each fabric element is defined by a unique domain
identification (domain ID) that ranges between 1 and 31. A domain ID of 0 is
invalid. Therefore, the theoretical limit of interconnected directors or switches
supported in a single fabric is 31.
For additional information, refer to “Large Fabric Design Implications” on
page 107. For the latest supported topology limits, refer to
http://h18000.www1.hp.com/products/stora geworks/san/documentation.html
or contact your local HP sales representative.
■ Heterogeneous fabric — Vendor interoperability in the fabric environment is
supported; therefore, fabric elements can include directors, edge switches, and
open-fabric compliant products supplied by original equipment manufacturers
(OEMs). To determine if interoperability is supported for a product, or if
communication restrictions apply, refer to the supporting publications for the
product or contact your HP representative.
■ Number of ISLs — The Director 2/64 supports 32 ISLs and the
Director 2/140 supports 70 ISLs. Edge Switches 2/16, 2/24, and 2/32 support
all ports. For redundancy, at least two ISLs should connect any pair of
director-class fabric elements. For information, contact your local HP sales
representative or refer to the following website:
http://h18000.www1.hp.com/products/stora geworks/san/documentation.html .