HP StorageWorks 2/16V Brocade Web Tools Administrator's Guide - Supporting Fab - Page 189

Chapter Administering Extended Fabrics 13 In this chapter This chapter contains the following information: • "About extended link buffer allocation," next • "Configuring a port for long distance" on page 169 About extended link buffer allocation As the distance between switches and the link speed increases, additional buffer-to-buffer credits are required to maintain maximum performance. The number of credits reserved for a port depends on the switch model and on the extended ISL mode for which it is configured. NOTE Because buffer credits are a switch resource, you must own the switch in order to modify Extended Fabric settings on a port. The Extended Fabric tab of the Switch Administration window displays information about the port speed, long-distance setting, and buffer credits, as shown in Figure 75 on page 168. Use this tab to configure the long-distance setting of a port. For detailed information on managing extended fabrics, see the Fabric OS Administrator's Guide. NOTE You do not need to use the Extended Fabrics feature unless the link is used over long distances. The Extended Fabric tab displays the following information: • Port Number • Buffer Limited-Indicates whether the port is buffer limited. A buffer-limited port can come online with fewer buffer credits allocated than its configuration specifies, allowing it to operate at a reduced bandwidth instead of being disabled for lack of buffers. Buffer-limited operation is supported for the L0 and LD extended ISL modes only and is persistent across reboots, switch disabling and enabling, and port disabling and enabling. • Port Speed-The port speed is displayed as follows: - 1G-1 Gbit/sec - 2G-2 Gbit/sec - 4G-4 Gbit/sec - N1-Negotiated 1 Gbit/sec - N2-Negotiated 2 Gbit/sec - N4-Negotiated 4 Gbit/sec Web Tools Administrator's Guide 167 Publication Number: 53-1000435-01