Marking; Configuring Dscp Classification By Interface; Configuring Port, Mac, And Vlan-Based Classification - Dell PowerConnect B-RX Configuration Manual

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Marking

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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:
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The following sections describe how to change the priority for each of the items listed above.
Although it is possible for a packet to qualify for an adjusted QoS priority based on more than one of
the criteria above, the system determines the priority it will use for forwarding as described in
"Processing of classified traffic"
472
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 89 through Table 92. This mapping is used for COS marking and determining the internal
priority when the trust level is COS.
mappings" on page 477.
Incoming port (sometimes called the ingress port)
Port-based VLAN membership
Static MAC entry
"Changing the CoS –> internal forwarding priority
on page 469.
BigIron RX Series Configuration Guide
53-1001986-01