Web Management Guide-R04

Table Of Contents
Chapter 9
| Class of Service
Layer 3/4 Priority Settings
– 260 –
Mapping CoS
Priorities to Internal
DSCP Values
Use the Traffic > Priority > CoS to DSCP page to maps CoS/CFI values in incoming
packets to per-hop behavior and drop precedence values for priority processing.
Command Usage
The default mapping of CoS to PHB values is shown in Table 17 on page 260.
Enter up to eight CoS/CFI paired values, per-hop behavior and drop
precedence.
If a packet arrives with a 802.1Q header but it is not an IP packet, then
the CoS/
CFI-to-PHB/Drop Precedence mapping table is used to generate
priority and
drop precedence values for internal processing. Note that priority tags in the
original packet are not modified by this command.
The internal DSCP consists of three bits for per-hop behavior (PHB) which
determines the queue to which a packet is sent; and two bits for drop
precedence (namely color) which is used to control traffic congestion.
Parameters
These parameters are displayed:
Port – Specifies a port.
CoS – CoS value in ingress packets. (Range: 0-7)
CFI – Canonical Format Indicator. Set to this parameter to “0” to indicate that
the MAC address information carried in the frame is in canonical format.
(Range: 0-1)
PHB – Per-hop behavior, or the priority used for this router hop. (Range: 0-7)
Drop Precedence – Drop precedence used for controlling traffic congestion.
(Range: 0 - Green, 3 - Yellow, 1 - Red)
Table 17: Default Mapping of CoS/CFI to Internal PHB/Drop Precedence
CFI
CoS
0 1
0(0,0)(0,0)
1(1,0)(1,0)
2(2,0)(2,0)
3(3,0)(3,0)
4(4,0)(4,0)
5(5,0)(5,0)
6(6,0)(6,0)
7(7,0)(7,0)