DCFM Professional Plus User Manual (53-1001774-01, June 2010)

DCFM Professional Plus User Manual 373
53-1001774-01
15
QoS configuration
QoS configuration involves configuring packet classification, mapping the priority and traffic class,
controlling congestion, and scheduling. The configuration of these QoS entities consist of CEE Map
and Traffic Class Map configuration.
In a Converged Enhanced Ethernet (CEE) configuration, Enhanced Transmission Selection (ETS)
and Priority-based flow control (PFC) are configured by utilizing a priority table, a priority group
table, and a priority traffic table. The Traffic Class Map is the mapping of user priority to traffic
class.
Enhanced Transmission Selection
Enhanced Transmission Selection (ETS) allows lower priority traffic classes to use available
bandwidth not being used by higher priority traffic classes and maximizes the use of available
bandwidth.
Priority-based flow control
Priority based flow control (PFC) is an enhancement to the existing pause mechanism in Ethernet.
PFC creates eight separate virtual links on the physical link and allows any of these links to be
paused and restarted independently, enabling the network to create a no-drop class of service for
an individual virtual link.
Table 23 shows examples of how priority grouping might be allocated in a 15-priority group
scenario.
TABLE 23
Priority group ID Bandwidth (%) Priority flow control
055 on
125 on
20 off
30 off
45 off
50 off
615 on
70 off
15.0-15.7 Strict priority
No bandwidth % configuration
allowed
on