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P
o 802.1q tag
2)
acket
ure the port to trust port priority. By default, port priority is trusted and the priority of a port
In this mode, the switch replaces the 802.1p priority of the received packet with the port priority,
rt priority of the receiving port in the
802.1p-to-local pr
ng table, and assigns the local p
z
Trusting packet priority
In this mode, the switch searches for the local prec
nce corresponding to the 802.1p priority of the
p
-to-local precedence mapping able and assigns the local precedence to the
p
ket.
T
riority trust mode
After a packet enters a switch, the switch sets the 802.1p priority and local precedence for the packet
according to its own capability and the corresponding rules.
1) For a packet carrying n
When a packet carrying no 802.1q tag reaches the port of a switch, the switch uses the port priority as
the 802.1p precedence value of the received packet, 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.
For an 802.1q tagged p
When an 802.1q tagged packet reaches the port of a switch, you can use the
priority trust
on the
receiving port to configure the port to trust packet priority or use the
priority
command on the receiving
port to config
is 0.
z
Trusting port priority
searches for the local precedence corresponding to the po
ecedence mappi
recedence to the packet.
ede
acket in the 802.1p
ac
t
able 45-5
shows the default 802.1p priority-to-local
ecedence mapping table. You can modify the
default mapping tables at the CLI. For detailed
figuration procedure, refer to
Configuring the
pr
con
Mapping between 802.1p Priority and Local Preced
e
enc
.
Table 45-5
802.1p priority-to-local precedence map
g table
pin
802.1p priority
Local precedence
0 2
1 0
2 1
3 3
4 4
5 5
6 6
7 7
Priority
Protocol
Prot
priority. You can set a new IP precedence or
ocol packets generated by a switch carry their own
DSCP precedence for the specific type of protocol packets to implement QoS.
45-7