Brocade Communications Systems Network Advisor 12.3.0, Руководство пользователя

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620 Brocade Network Advisor SAN User Manual
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QoS configuration
16
QoS configuration
QoS configuration involves configuring packet classification, mapping the priority and traffic class,
controlling congestion, and scheduling. The configuration of these QoS entities consists of DCB
Map and Traffic Class Map configuration.
In a Data Center Bridging (DCB) 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.
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
(CoS) for an individual virtual link.
Table 61 shows examples of how priority grouping might be allocated in a 15-priority group
scenario.
TABLE 61
Priority grouping allocated in a 15-priority group example
Priority group ID Bandwidth (%) Priority flow control
0 55 on
1 25 on
2 0 off
3 0 off
4 5 off
5 0 off
6 15 on
7 0 off
15.0-15.7 Strict priority
No bandwidth % configuration
allowed
on