Task 15: Plan A Multiswitch Fabric (Optional) - McDATA StorageWorks 2/140 - Director Switch Planning Manual

Task 15: Plan a Multiswitch Fabric (Optional)

If a multiswitch fabric topology is to be implemented, carefully plan
the physical characteristics and performance objectives of the
topology, including the proposed number of fabric elements,
characteristics of attached devices, cost, nondisruptive growth
requirements, and service requirements. Refer to
Planning for Multiswitch Fabric
Considerations for detailed information.
When two or more fabric elements are connected through ISLs to
form a fabric, the elements must have compatible operating
parameters, compatible name server zoning configurations, and
unique domain identifications (IDs). Planning for a fabric must be
carefully coordinated with planning for zoned configurations. The
following factors should be considered when planning for a
multiswitch fabric:
• Fabric topology limits - Consider the practical number of fabric
elements (theoretical maximum of 31, practical limit of 24),
number of ISLs per element, hop count (maximum of three), and
distance limitations (limited by port type and cable availability).
• Multiple ISLs for bandwidth and load balancing - Consider
using multiple ISLs to increase the total bandwidth available
between two fabric elements. If heavy traffic between devices is
expected, also consider multiple ISLs to create multiple
minimum-hop paths for load balancing.
If multiple ISL connections are planned, ensure the
OpenTrunking feature key is ordered with the Element Manager
application. This feature automatically provides dynamic load
balancing across multiple ISLs in a fabric environment.
• Principal switch selection - If required, plan which fabric
element is to be assigned principal switch duties for the fabric.
• Critical operations - Consider routing paths that transfer data for
critical operations directly through one director or fabric switch
and not through the fabric.
Planning and implementing a multiswitch fabric is a complex and
difficult task. Obtain planning assistance from McDATA's
professional services organization before implementing a fabric
topology.
Configuration Planning Tasks
Fabric
Support, and General Fabric Design
Configuration Planning Tasks
Topologies,
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