HP Brocade BladeSystem 4/12 Brocade OS Command Reference Manual Supporting Fab - Page 470

2 portCfgLongDistance portCfgLongDistance Configures a port to support long distance links. Synopsis portcfglongdistance [slotnumber/] portnumber [distance_level] [vc_translation_link_init] [desired_distance] Description Use this command to allocate enough full size frame buffers on a particular port to support a long distance link up to 500 Km. 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 credit 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. Refer to the FOS Administrator's Guide for details on platform-specific buffer credit models, long distance mode support, and maximum distance supported for specific hardware configurations. Operands This command has the following operands: slotnumber Specify the slot number (for bladed systems only), followed by a slash (/). portnumber Specify the number of the port to be configured relative to its slot for bladed systems. Use switchShow to display a list of valid ports. This operand is required. distance_level Specify a long distance level (the numerical value representing each distance_level is shown in parentheses): L0 (0) Specify L0 to configure the port as a regular port. A total of 20 full-size frame buffers are reserved for data traffic, regardless of the port's operating speed; therefore, the maximum supported link distance is up to 10 Km at 1 Gbps, up to 5 Km at 2 Gbps, up to 2 Km at 4 Gbps and up to 1 km at 8 Gbps, respectively. LE (3) Specify LE mode to configure an E_Ports distance greater than 5 Km and up to 10 Km. A total of 5, 10, or 20 full-size frame buffers are reserved for data traffic at port speeds of 1 Gbps, 2 Gbps, 4 Gbps, or 8 Gbps, respectively. LE does not require an Extended Fabrics license. LD (5) Specify LD for automatic long-distance configuration. The buffer credits for the given E_Port are automatically configured based on the actual link distance. Up to a total of 250 full-size frame buffers are reserved depending on the distance measured during E_Port initialization. Fabric OS v6.0 supports up to 500 km at 1 Gbps, up to 250 km at 2 Gbps, and up to 100 km at 4 Gbps and 8 Gbps, respectively. If a value for desired_distance is specified, it is used as the upper limit to the measured distance. 444 Fabric OS Command Reference 53-1000599-01