Introduction To Priority Mapping Tables - H3C S5810 Series Operation Manual

When an 802.1q tagged packet reaches the port of a switch, you can specify a priority trust mode for the
port, trusting port priority or trusting packet priority.
Trusting packet priority
In this mode, the switch searches for the set of precedence values corresponding to the trusted type
(802.1p precedence or DSCP precedence) of priority of the packet in the corresponding priority
mapping tables and assigns the set of matching precedence values to the packet.
Trusting port priority
In this mode, the switch replaces the 802.1p priority of the received packet with the port priority,
searches for the local precedence corresponding to the port priority of the receiving port in the
802.1p-to-local precedence mapping table, assigns the local precedence to the packet, and enqueues
the packet according to the local precedence value.
You can configure the priority trust mode of a port as required. The priority mapping process on a switch
is as shown in
Figure 3-1 Priority mapping process in the case of supporting trusting port priority
An S5810 series switch can trust one of the following two priority types:
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 dscp-lp mapping table based on the marked DSCP precedence for the
corresponding local precedence and marks the received packet with the local precedence.
Trusting the 802.1p precedence of received packets. In this mode, 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.

Introduction to Priority Mapping Tables

The device provides various types of priority mapping table, as listed below.
dot1p-dscp: 802.1p-precedence-to-DSCP mapping table.
dot1p-lp: 802.1p-precedence-to-local-precedence mapping table.
dscp-dot1p: DSCP-to-802.1p-precedence mapping table, which is applicable to only IP packets.
dscp-lp: DSCP-to-local-precedence mapping table, which is applicable to only IP packets.
Table 3-1 through
Figure 3-1.
Table 3-2 list the default priority mapping tables.
3-2