Configuring Queuing
Configuring the Queue Limit for a Specified Fabric Extender
At the Fabric Extender configuration level, you can control the queue limit for a specified Fabric Extender
for egress direction (from the network to the host). You can use a lower queue limit value on the Fabric
Extender to prevent one blocked receiver from affecting traffic that is sent to other noncongested receivers
("head-of-line blocking"). A higher queue limit provides better burst absorption and less head-of-line blocking
protection. You can use the
no
form of this command to allow the Fabric Extender to use all available hardware
space.
At the system level, you can set the queue limit for Fabric Extenders by using the
fex queue-limit
command. However, configuring the queue limit for a specific Fabric Extender will override the queue
limit configuration set at the system level for that Fabric Extender.
Note
You can specify the queue limit for the following Fabric Extenders:
•
Cisco Nexus 2148T Fabric Extender (48x1G 4x10G SFP+ Module)
•
Cisco Nexus 2224TP Fabric Extender (24x1G 2x10G SFP+ Module)
•
Cisco Nexus 2232P Fabric Extender (32x10G SFP+ 8x10G SFP+ Module)
•
Cisco Nexus 2248T Fabric Extender (48x1G 4x10G SFP+ Module)
•
Cisco Nexus N2248TP-E Fabric Extender (48x1G 4x10G Module)
•
Cisco Nexus N2348UPQ Fabric Extender (48x10G SFP+ 6x40G QSFP Module)
Procedure
Purpose
Command or Action
Enters global configuration mode.
switch#
configure terminal
Step 1
Specifies the Fabric Extender and enters the Fabric
Extender mode.
switch(config)#
fex fex-id
Step 2
Configures the queue limit for the specified Fabric
Extender. The queue limit is specified in bytes. The range
switch(config-fex)#
hardware
fex_card_type queue-limit
queue-limit
Step 3
is from 81920 to 652800 for a Cisco Nexus 2148T Fabric
Extender and from 2560 to 652800 for all other supported
Fabric Extenders.
This example shows how to restore the default queue limit on a Cisco Nexus 2248T Fabric Extender:
switch#
configure terminal
switch(config-if)#
fex 101
switch(config-fex)#
hardware N2248T queue-limit 327680
Cisco Nexus 5000 NX-OS Quality of Service Configuration Guide, Release 5.1(3)N2(1)
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Configuring Queuing and Flow Control
Configuring Queuing