Egress traffic processing exiting a device, Creating an egress encode policy map – 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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Egress Traffic processing exiting a device
4
•
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 IPv4v6 packet
4. EXP value in an incoming MPLS packet
5. PCP value in a tagged frame or PCP field or .1ad DE
Details of how to configure the force commands are provided in
“Configuring a force priority”
Egress Traffic processing exiting a device
The QoS operation on Egress Traffic of a Brocade device involves marking packets as they leave a
device on the egress port. As the packets are prepared to exit the device you can set the PCP,
DSCP, and EXP values in the packet headers. This process is described in
.
FIGURE 3
Logic flow of Egress QoS processing
Creating an egress encode policy map
The QoS value that a packet carries in its header when it exits a Brocade device on an egress
interface is determined by a specified mapping. Unless configured, this value once determined is
placed in an internal queue by using one of the default maps described in
on page 79. Alternately, the following commands can be used to define an alternate mapping:
•
pcp encode-map encode-map-name – This command allows you to map the internal priority
and drop precedence values of a packet into the PCP code point.
•
dscp encode-map encode-map-name – This command allows you to map the internal priority
and drop precedence values of a packet into the DSCP code point.
NOTE
DSCP encoding and decoding are not supported for MPLS packets.
•
exp encode-map encode-map-name – This command allows you to map the internal priority
and drop precedence values of a packet into the EXP code point.
Internal Packet with
attached Internal Priority
Drop Precedence
Count
Map Internal
Priority to
Egress Packet
Priority
To Egress Port