HP AP775A Cisco MDS 9000 Family Fabric Manager Configuration Guide - Release 4 - Page 491

Chapter 22 Configuring Generation 2 and Generation 3 Switching Modules Buffer Credit Allocation Send documentation comments to [email protected] 48-Port 4-Gbps Fibre Channel Module BB_Credit Buffers Table 22-11 lists the BB_credit buffer allocation for 48-port 4-Gbps Fibre Channel switching modules. Table 22-11 48-Port 4-Gbps Switching Module BB_Credit Buffer Allocation BB_Credit Buffer Allocation Default BB_credit buffers Maximum BB_credit buffers Total number of BB_credit buffers per module 1. ISL = E port or TE port. BB_Credit Buffers Per Port Dedicated Rate Mode 4-Gbps Speed ISL1 Fx Port 125 16 250 250 6000 Shared Rate Mode 4-Gbps Speed Fx Port 16 16 The following considerations apply to BB_credit buffers on 48-port 4-Gbps Fibre Channel switching modules: • BB_credit buffers for ISL connections can be configured from a minimum of 2 buffers to a maximum of 250 buffers for dedicated rate mode or 16 buffers for shared rate mode. • BB_credit buffers for Fx port mode connections can be configured. The minimum is 2 buffers and the maximum of 250 buffers for dedicated rate mode or 16 buffers for shared rate mode. • Performance buffers are not supported on this module. Each port group on the 48-port 4-Gbps Fibre Channel switching module consists of 12 ports. The ports in shared rate mode have bandwidth oversubscription of 2:1 by default. However, some configurations of the shared ports in a port group can have maximum bandwidth oversubscription of 4:1 (considering that each port group has 12.8-Gbps bandwidth). The following example configurations are supported by the 48-port 4-Gbps Fibre Channel switching modules: • Twelve ports with shared rate mode and 4-Gbps speed (4:1 oversubscription) (default) • One port with dedicated rate mode and 4-Gbps speed plus 11 ports with shared rate mode and 4-Gbps speed (5:1 oversubscription) • One port with dedicated rate mode and 4-Gbps speed plus 11 ports with shared rate mode and 2-Gbps speed (2.5:1 oversubscription) • Two ports with dedicated rate mode and 2-Gbps speed plus 10 ports with shared rate mode and 4-Gbps speed (5:1 oversubscription) • Two ports with dedicated rate mode and 2-Gbps speed plus 10 ports with shared rate mode and 2-Gbps speed (2.5:1 oversubscription) • Twelve ports with dedicated rate mode and 1-Gbps speed • Three ports with dedicated rate mode and 4-Gbps speed plus four ports with shared rate mode and 1-Gbps speed plus five ports put out-of-service (see Figure 22-8) OL-17256-03, Cisco MDS NX-OS Release 4.x Cisco MDS 9000 Family Fabric Manager Configuration Guide 22-17