Configuring Buffer-To-Buffer Credits - Cisco AP776A - Nexus Converged Network Switch 5020 Configuration Manual

Chapter 13 Configuring Interfaces
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
The receive BB_credit (fcrxbbcredit) value may be configured for each FC interface. In most cases, you
do not need to modify the default configuration.
The receive BB_credit values depend on the module type and the port mode, as follows:
For 16-port switching modules and full rate ports, the default value is 16 for Fx mode and 255 for E or
TE modes. The maximum value is 255 in all modes. This value can be changed as required.
For 32-port switching modules and host-optimized ports, the default value is 12 for Fx, E, and TE modes.
These values cannot be changed.
For Generation 2 and Generation 3 switching modules, see the
In the Cisco MDS 9100 Series, the groups of ports on the left outlined in white are full line rate. The
Note
other ports are host-optimized. Each group of 4 host-optimized ports have the same features as for the
32-port switching module.

Configuring Buffer-to-Buffer Credits

To configure BB_credits for a Fibre Channel interface, follow these steps:
Command
Step 1
switch# config t
switch(config)#
Step 2
switch(config)# interface fc1/1
switch(config-if)#
Step 3
switch(config-if)# switchport fcrxbbcredit
default
switch(config-if)# switchport fcrxbbcredit 5
switch(config-if)# switchport fcrxbbcredit 5
mode E
switch(config-if)# switchport fcrxbbcredit 5
mode Fx
Step 4
switch(config-if# do show int fc1/1
OL-18084-01, Cisco MDS NX-OS Release 4.x
"Buffer Pools" section on page
Purpose
Enters configuration mode.
Selects a Fibre Channel interface and enters
interface configuration submode.
Applies the default operational value to the
selected interface. The operational value depends
on the port mode. The default values are assigned
based on the port capabilities.
Assigns a BB_credit of 5 to the selected interface.
The range to assign BB_credits is between 1 and
255.
Assigns this value if the port is operating in E or
TE mode. The range to assign BB_credits is
between 1 and 255.
Assigns this value if the port is operating in F or
FL mode. The range to assign BB_credits is
between 1 and 255.
Displays the receive and transmit BB_credit
along with other pertinent interface information
for this interface.
Note The BB_credit values are correct at the
time the registers are read. They are
useful to verify situations when the data
traffic is slow.
Cisco MDS 9000 Family CLI Configuration Guide
Buffer Credits
15-9.
13-35