IBM SAN32M1, Installation And Service Manual

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SAN32M1 Fabric Switch Installation and Service Manual 8
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Domain ID assignment
- Each switch in a fabric is identified by a
unique domain ID that ranges from 1 through 31. A domain ID of
0 is invalid. If two operational fabrics join, they determine if any
domain ID conflicts exist between the fabrics. If one or more
conflicts exist, the E_Ports that form the interswitch link (ISL)
segment to prevent the fabrics from joining.
• Zoning - In a multiswitch fabric, zoning is configured on a
fabric-wide basis, and any change to the zoning configuration is
applied to all switches in the fabric. To ensure zoning is consistent
across a fabric, the following rules are enforced when two fabrics
(zoned or unzoned) join:
— Fabric A unzoned and Fabric B unzoned - The fabrics join
successfully, and the resulting fabric remains unzoned.
— Fabric A zoned and Fabric B unzoned - The fabrics join
successfully, and fabric B automatically inherits the zoning
configuration from fabric A.
— Fabric A unzoned and Fabric B zoned - The fabrics join
successfully, and fabric A automatically inherits the zoning
configuration from fabric B.
— Fabric A zoned and Fabric B zoned - The fabrics join
successfully only if the zone configurations can be merged. If
the fabrics cannot join, the connecting ports segment and the
fabrics remain independent.
Zone configurations for two fabrics are compatible (the zones can
join) if the active zone set name is identical for each fabric, and if
zones with the same name have identical elements.
• Port segmentation - When an ISL activates, the switches
exchange operating parameters to determine if they are
compatible and can join to form a single fabric. If incompatible,
the connecting E_Port at each switch segments to prevent the
creation of a single fabric. A segmented link transmits only Class
F traffic; the link does not transmit Class 2 or Class 3 traffic. The
following conditions cause ports to segment:
— Incompatible operating parameters - Either the resource
allocation time-out value (R_A_TOV) or error-detect time-out
value (E_D_TOV) is inconsistent between switches. To prevent
port segmentation, the same E_D_TOV and R_A_TOV must
be specified for each switch.