H3C Technologies H3C S3100 Series Switches - Manual (Page 586)

1-7
For incoming 802.1q tagged packets, you can configure the switch to trust packet priority with the
priority trust command or to trust port priority with the undo priority trust command. By default, the
S3100 series switches trust port priority.
z 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, and assigns the local precedence to the packet.
z Trusting packet priority
After configuring to trust packet priority, you can specify the trusted priority type, which can be 802.1p
priority, DSCP precedence, or IP precedence. With trusting packet priority enabled, the switch trusts the
802.1p priority of received packets.
Table 1-5 describes the three trusted packet priority types.
Table 1-5 Description on the three trusted packet priority types
Trusted priority type Description
802.1p priority
The switch searches for the local precedence corresponding to the
802.1p priority of the packet in the 802.1p-to-local precedence mapping
table and assigns the local precedence to the packet.
DSCP precedence
The switch searches for the local precedence corresponding to the
DSCP value of the packet in the DSCP-to-local precedence mapping
table and assigns the local precedence to the packet.
IP precedence
The switch searches for the local precedence corresponding to the IP
precedence of the packet in the IP-to-local precedence mapping table
and assigns the local precedence to the packet.
The S3100 series switches provide 802.1p-to-local-precedence, DSCP-to-local-precedence, and
IP-to-local-precedence mapping tables for priority mapping. Table 1-6 through Table 1-8 list the default
settings of these tables. You can configure these default priority mapping tables at the CLI. For detailed
configuration, refer to Configuring Priority Trust Mode .
Table 1-6 CoS-precedence-to-local-precedence mapping table
CoS Local precedence
0 1
1 0
2 0
3 1
4 2
5 2
6 3
7 3