Brocade BigIron RX Series Configuration Guide - Manual (Page 562)

484 BigIron RX Series Configuration Guide
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Marking
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• COS to DSCP Mapping – You can change the mapping between 802.1p (COS) values from the
default values shown in
Table 96 through Table 99 . This mapping is used for DSCP marking
when trust level is COS. Refer to “Changing the CoS –> DSCP mappings” on page 487.
• DSCP to DSCP Mapping – You can alter the DSCP value of a packet that is received to a value
configured on the switch. This mapping is used for DSCP marking when trust level is DSCP.
Refer to
“Changing the DSCP –> DSCP mappings” on page 488.
• DSCP to Internal Forwarding Priority Mapping – You can change the mapping between the
DSCP value and the Internal Forwarding priority value from the default values shown in
Table 96 through Table 99 . This mapping is used for COS marking and determining the internal
priority when the trust level is DSCP. Refer to “Changing the DSCP –> internal forwarding
priority mappings” on page 488.
• COS to Internal Forwarding Priority Mapping – You can change the mapping between 802.1p
(COS) values and the Internal Forwarding priority value from the default values shown in
Table 96 through Table 99 . This mapping is used for COS marking and determining the internal
priority when the trust level is COS. “Changing the CoS –> internal forwarding priority
mappings” on page 489.
Marking
Marking is the process of changing the packet’s QoS information (the 802.1p and DSCP
information in a packet) for the next hop. You can mark a packet’s Layer 2 CoS value, its Layer 3
DSCP value, or both values. The Layer 2 CoS or DSCP value the device marks in the packet is the
same value that results from mapping the packet’s QoS value into a Layer 2 CoS or DSCP value.
Marking is optional and is disabled by default. When marking is disabled, the device still performs
mappings for scheduling the packet, but leaves the packet’s QoS values unchanged when the
device forwards the packet.
Configuring DSCP classification by interface
You can configure DSCP classification on an interface to set the DSCP value of every packet that
arrives on the interface to a value that you configure. After the packet’s DSCP value has been set
using this command, it is subject to classification, marking, and scheduling operations that are
configured.
To configure the 1/1 interface to set all packets that arrive on it to a DSCP value of 23, use the
following command.
BigIron RX(config)# interface ethernet 1/1
BigIron RX(config-if-e1000-1/1)# dscp 23
Syntax: [no] dscp <num>
The <num> parameter can be any possible DSCP value from 0 to 63.
Configuring port, MAC, and VLAN-based classification
Assigning QoS priorities to traffic
By default, traffic is forwarded using the best-effort queue (qosp0). However, traffic can be
classified into different priorities, based on the following: