Users Guide

Fabric OS Administrator’s Guide 319
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Account management and Virtual Fabrics
11
ATTENTION
If you disable a base switch, all of the logical ISLs are broken and the logical switches cannot
communicate with each other unless they are connected by a physical ISL.
Base fabric
Base switch ports on different chassis can be connected together to form a fabric, called a base
fabric. Similar to other logical switches, the base switches must have the same FID to be
connected. If the base switches have different FIDs, the link between the switches is disabled.
The base fabric follows normal routing policies. As long as physical connectivity is available, the
base fabric maintains connectivity for the logical fabrics.
Logical ports
As shown in Figure 31, logical ISLs are formed to connect logical switches. A logical port represents
the ports at each end of a logical ISL. A logical port is a software construct only and does not
correspond to any physical port.
Most port commands are not supported on logical ports. For example, you cannot change the state
or configuration of a logical port.
The World Wide Name (WWN) for logical ports is in NAA=5 format, using the following syntax:
5n:nn:nn:nz:zz:zz:zx:xx
The NAA=5 syntax uses the following variables:
• nnnnnn is the Brocade Organizationally Unique Identifier (OUI).
• zzzzzz is the logical fabric serial number.
• xxx is the logical port number, in the range 0 through FFF.
Logical fabric formation
Fabric formation is not based on connectivity, but on the FIDs of the logical switches. The basic
order of fabric formation is as follows:
1. Base fabric forms.
2. Logical fabrics form when the base fabric is stable.
3. Traffic is initiated between the logical switches.
4. Devices begin recognizing one another.
Account management and Virtual Fabrics
When user accounts are created, they are assigned a list of logical fabrics to which they can log in and
a home logical fabric (home FID). When you connect to a physical chassis, the home FID defines the
logical switch to which you are logged in by default. You can change to a different logical switch
context, as described in “Changing the context to a different logical fabric” on page 334.