.Part 1 Architecture HP SAN Design Reference Guide 785351-001

Figure 7 Core-edge fabric (typical depiction)
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Core-edge fabric topologies are typically depicted as shown in Figure 7 (page 30), but can also
be depicted hierarchically as shown in Figure 8 (page 30). Both figures represent the same physical
implementation. How a topology is logically represented can help you understand the potential
performance of a core-edge topology.
Figure 8 Core-edge fabric (hierarchical depiction)
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Core-edge fabric types
The number of ISLs between edge and core switches—typically expressed as a fan-in ratio, such
as 7:1—characterizes the core-edge fabric types. The first number (7) indicates the number of
edge ports. The second number (1) indicates the number of ISLs used by the edge ports to connect
to a core switch in the fabric.
Fat and skinny trees
There are two core-edge fabric topology types: fat tree and skinny tree. Table 1 (page 31) describes
fat and skinny trees.
30 SAN fabric topologies