Cisco AP775A - Nexus Converged Network Switch 5010 Configuration Manual page 496

Buffer Credit Allocation
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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Note
BB_Credit Buffers for Fabric Switches
This section describes how buffer credits are allocated to Cisco MDS 9000 Fabric switches, and includes
the following topics:
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Cisco MDS 9134 Fabric Switch BB_Credit Buffers
Table 22-16
Table 22-16
BB_Credit Buffer Allocation Type
User-configurable BB_credit buffers on 4-Gbps
mode
Default BB_credit buffers
1. ISL = E port or TE port.
The following considerations apply to BB_credit buffers on 32-port 4-Gbps switches:
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Cisco MDS 9000 Family Fabric Manager Configuration Guide
22-22
By default, 512 performance buffers are preallocated and are shared by all the ports. These buffers
are configurable and the buffers are assigned to the port based on the availability of the buffers in
the shared pool.
There are 2488 extra buffers available as extended BB_credits after allocating all the default
BB_credit buffers for all the ports in ISL mode (5488 - (750 * 4)).
Extended BB_credits are allocated across all ports on the switch. That is, they are not allocated
by port group.
Cisco MDS 9134 Fabric Switch BB_Credit Buffers, page 22-22
Cisco MDS 9124 Fabric Switch BB_Credit Buffers, page 22-23
Cisco MDS 9222i Multiservice Modular Switch BB_Credit Buffers, page 22-23
lists the BB_credit buffer allocation for 32-port 4-Gbps Fibre Channel switches.
32-Port 4-Gbps Switching Module BB_Credit Buffer Allocation Defaults
BB_credit buffers can be configured from a minimum of 1 buffer to a maximum of 61 buffers per
port when the ports are in F mode and in 4-Gbps speed mode.
BB_credit buffers can be configured from a minimum of 2 buffers to a maximum of 64 buffers per
port when the ports are in auto or E mode and in 4-Gbps speed mode.
BB_credit buffers can be configured from a minimum of 64 buffers to a maximum of 64 buffers per
port when a port is in 10-Gbps speed mode. There can be only one port per port group configured
in 10-Gbps mode. The rest of the three ports must be in down state.
BB_credit buffers for Fx port mode connections can be configured from a minimum of 2 buffers to
a maximum of 64 buffers.
Chapter 22 Configuring Generation 2 and Generation 3 Switching Modules
BB_Credit
Buffers Per
Port Group
64
64
OL-17256-03, Cisco MDS NX-OS Release 4.x
BB_Credit Buffers Per Port
1
ISL Fx Port
64 64
16 16