Priority-based flow control, Creating a dcb map – Brocade Network Advisor SAN + IP User Manual v12.1.0 User Manual
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Brocade Network Advisor SAN + IP User Manual
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QoS configuration
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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.
shows examples of how priority grouping might be allocated in a 15-priority group
scenario.
Creating a DCB map
The procedure in this section applies 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. Refer to
for an example of priority group configuration.
NOTE
The 10 Gbps DCB/FC switch module can have only one DCB map.
1. Select Configure > DCB.
The DCB Configuration dialog box displays, showing the status of all DCB-related hardware and
functions.
2. Select a switch, and click Edit.
3. Click the QoS tab on the Edit Switch dialog box.
The QoS dialog box displays, as shown in
Figure 246
.
TABLE 90
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