About Performance Buffers; Configuring Performance Buffers; About Extended Bb_Credits - Cisco AP776A - Nexus Converged Network Switch 5020 Configuration Manual

Buffer Credits
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
This example shows the output of the do show int fc1/1 command:
intfc1/1 is up

About Performance Buffers

Performance buffers are not supported on the Cisco MDS 9124 Fabric Switch, the Cisco Fabric Switch
Note
for HP c-Class BladeSystem, and the Cisco Fabric Switch for IBM BladeCenter.
Regardless of the configured receive BB_credit value, additional buffers, called performance buffers,
improve switch port performance. Instead of relying on the built-in switch algorithm, you can manually
configure the performance buffer value for specific applications (for example, forwarding frames over
FCIP interfaces).
For each physical Fibre Channel interface in any switch in the Cisco MDS 9000 Family, you can specify
the amount of performance buffers allocated in addition to the configured receive BB_credit value.
The default performance buffer value is 0. If you use the default option, the built-in algorithm is used.
If you do not specify this command, the default option is automatically used.

Configuring Performance Buffers

To configure performance buffers for a Fibre Channel interface, follow these steps:
Command
Step 1
switch# config t
Step 2
switch(config)# interface fc1/1
switch(config-if)#
Step 3
switch(config-if)# switchport
fcrxbbcredit performance-buffers 45
switch(config-if)# switchport
fcrxbbcredit performance-buffers default
Note Use the show interface bbcredit command to display performance buffer values and other BB_credit
information.

About Extended BB_credits

You can use the extended BB_credits flow control mechanism in addition to BB_credits for long haul
links.
This section includes the following topics:
•
Cisco MDS 9000 Family CLI Configuration Guide
13-36
...
16 receive B2B credit remaining
3 transmit B2B credit remaining
Extended BB_credits on Generation 1 Switching Modules, page 13-37
Chapter 13
Purpose
Enters configuration mode.
Selects a Fibre Channel interface and enters interface
configuration submode.
Assigns a performance buffer of 45 to the selected
interface. The value ranges from 1 to 145.
Reverts to the factory default of using the built-in
algorithm.
OL-18084-01, Cisco MDS NX-OS Release 4.x
Configuring Interfaces