Users Guide

Fabric OS Administrator’s Guide 323
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Limitations and restrictions of Virtual Fabrics
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The maximum number of logical switches per chassis varies depending on the switch model.
Table 61 lists the supported platforms and the maximum number of logical switches (including the
default logical switch) supported on each.
Refer to “Supported port configurations in Brocade Backbones” on page 321 for restrictions on the
default logical switch.
If a blade slot is being decommissioned and has ports configured in logical switches, it is
recommended that the logical port assignments be removed from that blade before removing the
blade. This ensures a seamless transition for any new port or AP blade that might occupy that slot
in the future. This does not apply if you are simply replacing a blade of the same type.
Restrictions on XISLs
The Allow XISL Use option under the configure command, allows a logical switch to use XISLs in the
base switch as well as any standard ISLs that are connected to that logical switch. To allow or
disallow XISL use for a logical switch, see “Configuring a logical switch to use XISLs” on page 333.
The following restrictions apply to XISL use. XISL use is not permitted in any of the following
scenarios:
• The logical switch has ICL ports.
• The logical switch is the default logical switch in the Brocade DCX, DCX-4S, or DCX 8510 family.
• The logical switch is a base switch.
• The logical switch is an edge switch for an FC router.
In this case, if the logical switch is enabled, you cannot allow XISL use. If the logical switch is
disabled or has not yet joined the edge fabric, you can allow XISL use; however, fabric
segmentation occurs when the logical switch is enabled or is connected to an edge fabric.
NOTE
Using XISL and fmsmode at the same time is permitted, but this combination will only work in a
one-hop topology.
TABLE 61 Maximum number of logical switches per chassis
Platform Maximum number of logical switches
Brocade DCX 8
Brocade DCX-4S 8
Brocade DCX 8510 family 8
Brocade 5300 4
Brocade 5100 3
Brocade 6510 4
Brocade 6520 4
Brocade 7800 4
Brocade VA-40FC 3