FW V06.XX/HAFM SW V08.02.00 HP StorageWorks SAN High Availability Planning Guide (AA-RS2DD-TE, July 2004)

Planning Considerations for Fibre Channel Topologies
93SAN High Availability Planning Guide
Figure 37: Ring fabric
Ring fabrics are generally more expensive than cascaded fabrics, are also easy to
deploy, provide a simple solution to add additional fabric devices, and can solve
hop-count problems inherent to cascaded fabrics. Ring fabrics also have increased
reliability because traffic can route around a single ISL, director, or switch failure
(subject to hop count limitations).
Like cascaded fabrics, ring fabrics are well suited for applications where data
access is local, but not for applications that require any-to-any connectivity. In
addition, ring fabrics are useful when connecting SANs over a MAN or WAN.
These networks typically use a ring topology.
Mesh Fabric
There are two types of mesh fabrics: full mesh and modified (or partial) mesh. In a
full-mesh topology, every director or switch is directly connected to all directors
and switches in the fabric. The maximum hop count between fabric-attached
devices is one hop. Figure 38 illustrates a full-mesh fabric topology.
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Fabric Connection