R21xx-HP FlexFabric 11900 ACL and QoS Configuration Guide

26
Priority trust mode on a port
The priority trust mode on a port determines which priority is used for priority mapping table lookup. Port
priority was introduced to use for priority mapping in addition to the priority fields carried in packets. The
Switch Series provides the following priority trust modes:
• Using the 802.1p priority carried in packets for priority mapping.
Table 3 Priority mapping results of trusting the 802.1p priority (when the default dot1p-lp priority
mapping table is used)
802.1p priority carried in
p
ackets
Local precedence Queue ID
0 2 2
1 0 0
2 1 1
3 3 3
4 4 4
5 5 5
6 6 6
7 7 7
NOTE:
W
hen the 802.1p priority carried in packets is trusted, the port priority is used for priority mappin
g
for
packets which do not carry VLAN tags (namely, do not carry 802.1p priorities). Table 3 shows the
priority
mapping results.
• Using the DSCP carried in packets for priority mapping.
Table 4 Priority mapping results of trusting the DSCP (when the default dscp-dot1p and dot1p-lp
priority mapping tables are used)
DSCP value carried in
p
ackets Local
p
recedence Queue ID
0 to 7 2 2
8 to 15 0 0
16 to 23 1 1
24 to 31 3 3
32 to 39 4 4
40 to 47 5 5
48 to 55 6 6
56 to 63 7 7
The priority mapping process varies with the priority trust modes. For more information, see the
subsequent section.