Qos Configuration; Priority-Based Flow Control; Creating A Dcb Map - Brocade Communications Systems StoreFabric SN6500B User Manual

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 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 60
scenario.
TABLE 60

Creating a DCB map

This procedure is applicable only for Fabric OS versions earlier than Fabric OS 7.0.
When you create a DCB map, each of the Class of Service (CoS) options (0-7) must be mapped to
at least one of the Priority Group IDs (0-7) and the total bandwidth percentage must equal 100. All
QoS, DCB map, and Traffic Class map configurations apply to all ports in a LAG.
There can be, at the most, 16 entries in the Priority Group table. Eight of the entries are Strict
Priority entries with a Priority Group ID (15.0 - 15.7) and eight are user-definable entries with a
Priority Group ID of 0-7. See
Brocade Network Advisor SAN User Manual
53-1002696-01
shows examples of how priority grouping might be allocated in a 15-priority group
Priority grouping allocated in a 15-priority group example
Priority group ID
0
1
2
3
4
5
6
7
15.0-15.7
No bandwidth % configuration
Table 60
Bandwidth (%)
55
25
0
0
5
0
15
0
Strict priority
allowed
for an example of priority group configuration.
16

QoS configuration

Priority flow control
on
on
off
off
off
off
on
off
on
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