Portcfglongdistance - Brocade Communications Systems 8 Command Reference Manual

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portCfgLongDistance

portCfgLongDistance
Configures a port to support long distance links.
Synopsis portcfglongdistance [slot/]port [distance_level] [vc_translation_link_init] [desired_distance]
Description Use this command to allocate sufficient numbers of full size frame buffers on a particular port or to
support a specified long distance link. The port can only be used as an E_Port. Changes made by
this command are persistent across switch reboots and power cycles. This configuration can be
cleared but not set on VE/VEX_Ports.
Long distance configuration allows native FC ports to run WAN/LAN connections. It ensures that
the full bandwidth of a link or trunk can be utilized for a particular long distance configuration. The
receiving port must have sufficient buffers available, so that the transmitting port can stuff the link
with enough frames to fill the entire length of the link. As the distance between switches and the
link speed increases, additional buffer-to-buffer credits are required to maintain maximum
performance. If a port is configured as a long distance port, the remaining ports of that port group
could be disabled, fail to initialize, or move to "buffer limited" mode due to a lack of frame buffer
credits.
The number of credits reserved for a port depends on the switch model and on the extended fabric
mode for which it is configured. Not all distance modes are supported by all platforms. For
example, the FC10-6 only supports LO and LS up to 120 km at 10 Gbps, and the maximum
supported distance can vary greatly depending on switch platform and available buffers. Refer to
the Fabric OS Administrator's Guide for details on platform-specific buffer credit models, long
distance mode support, and maximum distance supported for specific hardware configurations.
Notes This command requires an Extended Fabrics license.
The execution of this command is subject to Virtual Fabric or Admin Domain restrictions that may
be in place. Refer to chapter 1, "Using Fabric OS commands" and Appendix A, "Command
Availability" for details.
The long distance modes L0.5, L1, and L2 are no longer supported in v5.3.0 and later.
A long-distance link can also be configured to be part of a trunk group. Refer to portCfgTrunkPort
help for details.
When a port is configured as a long-distance port, the output of portShow and switchShow displays
the long-distance level. Refer to portShow help and switchShow help for details.
The portCfgISLMode and portCfgLongDistance LE, LD, or LS levels y can be enabled at the same
time. Such an ISL uses the R_RDY mode of flow control over the long distance link. While using
R_RDY mode flow control, an E_Port cannot form trunk groups of long-distance links even if the
trunking is enabled. This feature is not backward compatible with firmware versions that do not
support it.
Ctrl-D cancels the configuration update.
The Fabric OS port configuration commands are not supported on FCoE ports.
658 Fabric OS Command Reference
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