Priority Mapping Overview - 3Com MSR 50 Series Configuration Manual

87
Priority Mapping
Overview
P M
RIORITY
When packets enter the router, the router will allocate a series of parameters such
as 802. 1p priority and local priority for the packets according to its own
supporting condition and corresponding rules.
The local priority is defined as follows:
Local priority: the router allocates priority that is meaningful locally for packets
■
to correspond with the queue number of egress port. Packets with a higher
local priority will be processed first. Refer to your specific device for the process
mode.
The router provides two port priority trust modes:
Packet priority-trusted mode, in which the priority parameters to be assigned
■
to packets are determined by looking up the priority mapping table using the
priorities of the packets.
Port priority-trusted mode, in which the local priorities to be assigned to
■
packets are determined by the priorities of the ports through which the packets
are received.
Port priority trust mode can be configured as required. The packet priority
mapping process on the router is shown in
Figure 471 Priority mapping process when the port priority trust mode is supported
N N
Priority of trusted port Priority of trusted port
Packet Packet
Receiving interface Receiving interface
The router supports dot10-lp priority mapping tables that respectively has
corresponding priority mapping relationships. The priority mapping tables and
their default values are shown as follows.
The default value of mapping table is shown as follows.
APPING
Figure
Priority of trusted packet Priority of trusted packet
Y Y
471.
Under the priority trust mode configured Under the priority trust mode configured
on the receiving port, search priority on the receiving port, search priority
mapping table according to relevant mapping table according to relevant
parameters such as packet allocation parameters such as packet allocation
priority. priority.
Allocate local priority for packets through Allocate local priority for packets through
one-to-one mapping according to the port one-to-one mapping according to the port
priority of receiving port. priority of receiving port.