H3C Technologies H3C WX6000 Series Access Controllers - Manual (Page 447)

47-1
47
Priority Mapping
When configuring priority mapping, go to these sections for information you are interested in:
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Priority Mapping Overview
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Configuring a Priority Mapping Table
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Configuring the Port Priority
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Configuring Port Priority Trust Mode
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Displaying and Maintaining Priority Mapping
Priority Mapping Overview
When a packet reaches a switch, the switch assigns the packet parameters according to it configuration,
such as 802.1p precedence, DSCP precedence, IP precedence, local precedence, and drop
precedence.
The local precedence and drop precedence are described as follows.
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Local precedence is the precedence that the switch assigns to a packet and it is corresponding to
the number of an outbound queue on the port. Local precedence takes effect only on the local
switch.
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Drop precedence is a parameter that is referred to when dropping packets. The higher the drop
precedence, the more likely a packet is dropped.
The H3C WX6103 access controller switch interface boards provide the following two priority trust
modes:
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Trusting the DSCP precedence of received packets. In this mode, the switch searches the
dscp-dot1p/dp/dscp mapping table based on the DSCP precedence of the received packet for
the 802.1p precedence/drop precedence/DSCP precedence to be used to mark the packet. Then
the switch searches the dot1p-lp mapping table based on the marked 802.1p precedence for the
corresponding local precedence and marks the received packet with the local precedence.
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Trusting the 802.1p precedence of received packets. In this mode, if a packet is received without
an 802.1q tag, the switch takes the priority of the receiving port as the 802.1p precedence of the
packet and then based on the priority searches the dot1p-dp/lp mapping table for the local/drop
precedence for the packet. If packet is received with an 802.1q tag, the switch searches the
dot1p-dp/lp mapping table based on the 802.1p precedence in the tag for local/drop precedence
for the packet.
The default dot1p-lp/dp mapping and dscp-dot1p/dp/dscp mapping provided by the H3C WX6103
access controller switch interface boards are shown in the following two tables.
Table 47-1 The default values of dot1p-lp mapping and dot1p-dp mapping
Imported priority value dot1p-lp mapping dot1p-dp mapping
802.1p precedence (dot1p) Local precedence (lp) Drop precedence (dp)
0 2 0