Brocade Fabric OS Administrator's Guide Supporting Fabric OS v6.3.0 (53-1001336-02, November 2009)

Fabric OS Administrator’s Guide 427

53-1001336-02

QoS: SID/DID traffic prioritization

where id is a flow identifier that designates a specific virtual channel for the traffic flow and xxxxx is

the user-defined portion of the name. For example, the following are valid QoS zone names:

QOSH3_HighPriorityTraffic

QOSL1_LowPriorityZone

The switch automatically sets the priority for the “host,target” pairs specified in the zones based on

the priority level (H or L) in the zone name.

The flow id allows you to have control over the VC assignment and control over balancing the flows

throughout the fabric. The id is from 1–5 for high priority traffic, which corresponds to VCs 10–14.

For low priority traffic, the id is from 1–2, which corresponds to VCs 8 and 9. The id is optional; if it

is not specified, the virtual channels are allocated using a round-robin scheme.

NOTE

If a QoS zone name prefix is specified in an LSAN zone (a zone beginning with prefix "LSAN_"), the

QoS tag is ignored. Only the first prefix in a zone name is recognized. For example, a zone with the

name "LSAN_QOSH_zone1" is recognized as an LSAN zone and not a QoS zone.

See “QoS over FC routers” on page 428 for additional considerations when using QoS to prioritize

traffic between device pairs in different edge fabrics.

For example, Figure 64 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 64 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

Domain 1 Domain 3

Domain 4

Domain 2

= High priority

= Medium priority

= Low priority