CLI Reference Guide-R05

Chapter 20 | Class of Service Commands
Priority Commands (Layer 3 and 4)
– 573 –
Default Setting
Command Mode
Global Configuration
Command Usage
◆ The default mapping of CoS to PHB values shown in Table 112 is based on the
recommended settings in IEEE 802.1p for mapping CoS values to output
queues.
◆ Enter a value pair for the internal per-hop behavior and drop precedence,
followed by the keyword “from” and then up to eight CoS/CFI paired values
separated by spaces.
◆ 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.
◆ The specified mapping applies to all interfaces.
Example
Console(config)#qos map cos-dscp 0 0 from 0 1
Console(config)#
Table 112: 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)