.SAN design reference guide Vol. 1-5 785350-001

SAN scaling and routing

This section describes two methods for increasing the size of SANs:

• Increase the Fibre Channel switch capability within a fabric.

• Connect independent fabrics using a Fibre Channel router, Virtual Fabrics with IFR, or VSANs

with IVR.

Switch scaling

The switches that make up fabrics define the fabric limits. This section describes the relationship

between switches.

Switch scaling limits

Adding ports to a fabric means increasing the number of switches in the fabric or increasing the

number of ports per switch. For large fabrics, adding ports may not be possible unless the limits

for total port count and total switch count are increased.

Each Fibre Channel switch product line has its own limits for total port count and switch count. You

must ensure that a new or modified SAN design complies with these limits.

NOTE: Other limits, such as hop counts and link distances, also apply. For more information,

see:

• “B-series switches and fabric rules” (page 91)

• “C-series switches and fabric rules” (page 123)

• “H-series switches and fabric rules” (page 140)

For a SAN design to meet the total port count and total switch count limits, the following

configuration restrictions are enforced:

• The fabric size limit for total port or total switch count must not be exceeded.

• The use of several small switches to reach a high total port count number is not acceptable if

the design exceeds the total switch count limit.

• The use of several high-port-count switches is not acceptable if the design exceeds the total

port count limit.

For fabric configurations, HP defines the maximum supported port and switch counts.

Fabric services limits

Fabric services provide coordination between all switches in a fabric. Increasing fabric size

increases the overhead associated with coordination. Fabric services include:

• Fabric Login Server

• State Change

• Notification Server

• Name/Directory Server

• Zone Server

• Key Server

• Time Server

• Simple Name Service

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