HP A7533A - Brocade 4Gb SAN Switch Base, Administrator'S Manual

Page: 364 / 576

362 Optimizing fabric behavior
The switch automatically sets the priority for the host,target pairs specified in the zones based on the
priority level in the zone name.
NOTE: QoS can be used for device pairs that exist within the same fabric only. QoS priority information
is not passed over EX_ or VEX_Ports and should not be used for devices in separate fabrics.
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.
For example, Figure 56 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_Zone1Members: H1, S1
QOSL_Zone3Members: H1, H2, S3
QoS on E_Ports
In addition to configuring the hosts and targets in a zone, you must also enable QoS on individual E_Ports
that might carry traffic between the given host and target pairs. Path selection between the host,target pairs
is governed by FSPF rules and is not affected by QoS priorities. By default, QoS is enabled on E_Ports in
port configuration. For example, in Figure 57 , QoS should be enabled on the encircled E_Ports.
7
12
3
14
15
16
8
13
Domain 1 Domain 3
Domain 4 Domain 2
H1
1 9
S3
S2
S1
H2
= High priority
= Medium priority
= Low priority