Dell Brocade G620 Brocade 8.0.1 Fabric OS Command Reference - Page 719

portCfgLongDistance portCfgLongDistance Configures a port to support long distance links. Synopsis portcfglongdistance [slot/]port [distance_level] [vc_translation_link_init] [-distance distance] | [-buffer buffers] [-framesize frame_size] [-fecenable | -fecdisable] Description Use this command to allocate frame buffer credits to a port or to configure 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. 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 restrictions that may be in place. Refer to "Using Fabric OS Commands" and "Command Availability" for details. 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 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. Operands This command has the following operands: slot Specifies the slot number (for bladed systems only), followed by a slash (/). Brocade Fabric OS Command Reference 695 53-1004112-02