Brocade Communications Systems 8 Command Reference Manual page 168

2
configure
Data Field Size
Sequence-Level Switching
Disable Device Probing
Suppress Class F Traffic
Per-frame Route Priority
Long Distance Fabric
BB Credit
Insistent Domain ID Mode
Virtual Channel Settings
The switch enables fine-tuning for a specific application by configuring the parameters for eight
virtual channels. The first two virtual channels are reserved for switch internal functions and are
not available for modification.
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The data field size specifies the largest possible value, in bytes, for the size of
a type 1 (data) frame. The switch advertises this value to other switches in
the fabric during construction of the fabric as well as to other devices when
they connect to the fabric. Setting this parameter to a value smaller than
2112 might result in decreased performance.
When sequence-level switching is set to 1, frames of the same sequence
from a particular source are transmitted as a group. When this feature is set
to 0, frames are transmitted interleaved among multiple sequences.
Under normal conditions, sequence-level switching should be disabled for
better performance. However, some host adapters have performance issues
when receiving interleaved frames from multiple sequences. When there are
such devices attached to the fabric, sequence-level switching should be
enabled.
When disable device probing is set to 1, devices that do not register with the
Name Server will not be present in the Name Server data base. Set this mode
only if the switch's N_Port discovery process (PLOGI, PRLI, INQUIRY) causes
an attached device to fail.
By default, the switch can send Class F frames. When this option is turned on,
Class F traffic is converted to Class 2 traffic before being transmitted.
In addition to the eight virtual channels used in frame routing priority, support
is also available for per-frame-based prioritization when this value is set.
When Per-frame Route Priority is set to 1, the virtual channel ID is used in
conjunction with a frame header to form the final virtual channel ID.
When this mode is set to 1, ISLs in a fabric can be up to 100 km long. The
exact distance level is determined by the per-port configuration on the
E_Ports of each ISL. Both E_Ports in an ISL must be configured to run the
same long-distance level; otherwise, the fabric will be segmented.
An Extended Fabrics license is required to set this mode.
The buffer-to-buffer (BB) credit represents the number of buffers available to
attached devices for frame receipt. The range of allowed values varies
depending on other system settings (see Unicast-only Operation). BB credits
are not supported on 4G platforms. Refer to the Fabric OS Administrator's
Guide for more information on platform-specific BB Credit limitations.
When this mode is set, the switch attempts to acquire from the fabric the
domain number programmed in its "Switch Fabric Settings." If the operation
fails, the switch will segment from the fabric.
Fabric OS Command Reference
53-1001764-02