Reference Guide

As examples, “QOSH3_HighPriorityTraffic” and “QOSL1_LowPriorityZone” are both valid QoS zone names.
Each priority level is allocated to different virtual channels (VCs). High-priority flows receive more fabric resources than medium-priority
flows, which receive more resources than low-priority flows. For example, you could assign online transaction processing (OLTP) to a
high priority zone and backup traffic to a low priority zone. The flow id allows you to have control over the VC assignment and balancing
the flows throughout the fabric.
The id range is as follows:
∙ 1–5 for high-priority traffic, which corresponds to VCs 10–14.
∙ 1–4 for medium-priority traffic, which corresponds to VCs 2–5. Note, however, that the virtual channels for medium-priority
traffic are always allocated by a round-robin scheme, regardless of the id value.
∙ 1–2 for low-priority traffic, which corresponds to VCs 8 and 9.
The following figure shows a fabric with two hosts (H1, H2) and three targets (S1, S2, S3). The traffic prioritization is as follows:
∙ Traffic between H1 and S1 is high priority.
∙ Traffic between H1 and S3 and between H2 and S3 is low priority.
∙ All other traffic is medium priority, which is the default.
FIGURE 56 QoS traffic prioritization
For this fabric, you could set up the following QoS zones:
QOSH_Zone1 Members: H1, S1
QOSL_Zone3 Members: H1, H2, S3
Optimizing Fabric Behavior
Brocade Fabric OS Administration Guide, 8.0.1
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