Forcing the drop precedence of a packet, Configuring qos, Configuring a force priority – Brocade Multi-Service IronWare QoS and Traffic Management Configuration Guide (Supporting R05.6.00) User Manual
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Multi-Service IronWare QoS and Traffic Management Configuration Guide
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Forcing the drop precedence of a packet
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Forcing the drop precedence of a packet
Once a packet’s ingress drop precedence has been mapped, the values that will be used for
processing on the device are determined by either forcing or merging.
There are a variety of commands to “force” the drop precedence of a packet based on the following
criteria:
•
Forced to a drop precedence configured for a specific ingress port. The drop-precedence force
command is configured at the interface where you want it to be applied.
•
Forced to a drop precedence that is obtained from the DSCP priority bits. The qos dscp force
command is configured at the interface where you want it to be applied.
•
Forced to a drop precedence that is obtained from the PCP priority bits. The qos pcp force
command is configured at the interface where you want it to be applied.
•
Forced to a drop precedence that is based on an ACL match. The drop-precedence-force
keyword can be used within an ACL to apply a priority to specified traffic.
If multiple commands containing the force keyword are specified, the command with the highest
precedence will take effect as determined by the following order.
1. ACL match
2. Physical port’s drop precedence value
3. DSCP value in an incoming IPv4 packet
4. PCP value in a tagged frame or PCP
Details of how to configure the force commands are provided in
“Configuring a force priority”
Configuring QoS
The QoS configuration process involves separate procedures for Ingress and Egress QoS
Processing as described in the following major sections.
Configuring QoS procedures applicable to
Ingress and Egress
The following procedures are required to configure procedures applicable to both Ingress and
Egress QoS Processing on a Brocade device:
•
Support for QoS Configurations on LAG Ports – If you are configuring the enhanced QoS feature
on ports within a LAG, refer to
“Configuring port-level QoS commands on LAG ports”
Configuring a force priority
In situations where there are conflicting priority values for packets on an Ingress port, that conflict
can be resolved by performing a priority merge or by using a force command to direct the device to
use a particular value above other values. A force command can be configured for each of the
following: