Cisco MDS 9000 Series Configuration Manual page 121

Chapter 4 Configuring Interface Buffers
S e n d d o c u m e n t a t i o n c o m m e n t s t o m d s f e e d b a c k - d o c @ c i s c o . c o m
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4/44-Port 8-Gbps Host-Optimized Fibre Channel Module BB_Credit Buffers
Table 4-3
Table 4-3
BB_Credit Buffer Allocation
Default BB_credit buffers
Maximum BB_credit buffers
Total number of BB_credit buffers per module
The following guidelines apply to BB_credit buffers on 4/44-port 8-Gbps Fibre Channel switching
modules:
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Each port group on the 24-port 8-Gbps Fibre Channel switching module consists of 12 ports. The ports
in shared rate mode in a port group can have a maximum bandwidth oversubscription of 10:1 considering
that each port group has 12.8-Gbps bandwidth.
The following example configurations are supported by the 4/44-port 8-Gbps Fibre Channel switching
modules:
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OL-19445-02, Cisco MDS NX-OS Release 4.2(x)
Three ports with dedicated rate mode and 4-Gbps speed
lists the BB_credit buffer allocation for the 4/44-port 8-Gbps Fibre Channel switching module.
4/44-Port 8-Gbps Switching Module BB_Credit Buffer Allocation
BB_credit buffers for ISL connections can be configured from a minimum of 2 buffers to a
maximum of 500 buffers for dedicated 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 32 buffers for shared rate mode.
Performance buffers are not supported on this module.
Twelve ports with shared rate mode and 4-Gbps speed (5:1 oversubscription) (default)
One port with dedicated rate mode and 8-Gbps speed plus
eleven ports with shared rate mode and 4-Gbps speed (10:1 oversubscription)
One port with dedicated rate mode and 4-Gbps speed plus
three ports with dedicated rate mode and 3-Gbps speed plus
eight ports with shared rate mode and 4-Gbps speed (2:1 oversubscription)
Twelve ports with dedicated rate mode and 1-Gbps speed
BB_Credit Buffers Per Port
Dedicated Rate Mode
8-Gbps Speed
ISL Fx Port
125 32
250 250
6000
Cisco MDS 9000 Family NX-OS Interfaces Configuration Guide
Buffer Pools
Shared Rate Mode
8-Gbps Speed
Fx Port
32
32
4-9