Port 4-Gbps Fibre Channel Module Bb_Credit Buffers - Cisco AP776A - Nexus Converged Network Switch 5020 Configuration Manual

Chapter 15 Configuring Generation 2 and Generation 3 Switching Modules
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

48-Port 4-Gbps Fibre Channel Module BB_Credit Buffers

Table 15-10
Table 15-10
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.
The following considerations apply to BB_credit buffers on 48-port 4-Gbps Fibre Channel switching
modules:
•
•
•
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:
•
•
•
•
•
•
•
OL-18084-01, Cisco MDS NX-OS Release 4.x
lists the BB_credit buffer allocation for 48-port 4-Gbps Fibre Channel switching modules.
48-Port 4-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 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.
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
BB_Credit Buffers Per Port
Dedicated Rate Mode
4-Gbps Speed
1
ISL
125
250
6000
Figure 15-6)
Cisco MDS 9000 Family CLI Configuration Guide
Buffer Credit Allocation
Shared Rate Mode
4-Gbps Speed
Fx Port Fx Port
16 16
250 16
15-15