410 Fabric OS Administrator’s Guide
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QoS zones
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High availability considerations for traffic prioritization

If the standby CP is running a Fabric OS version earlier than 6.3.0 and is synchronized with the
active CP, then QoS zones using D,I notation cannot be created. If the standby CP is not
synchronized or if no standby CP exists, then the QoS zone creation succeeds.
If QoS zones using D,I notation exist in either the defined or active configuration and the standby
CP tries to synchronize with the active CP, the synchronization fails if the standby CP is running a
Fabric OS version earlier than 6.3.0. Synchronization can succeed only if the QoS D,I zones are
removed.

Supported configurations for traffic prioritization

Note the following configuration rules for traffic prioritization:
All switches in the fabric must be running Fabric OS v6.0.0 or later.
ATTENTION
If QoS traffic crosses an ISL for a switch running a firmware version earlier than Fabric OS
v6.0.0, the frames are dropped.
By default, all devices are assigned medium priority.
-To be assigned high or low priority, hosts and targets must be connected to one of the
following:
Brocade 300
Brocade 5100
Brocade 5300
Brocade 5410
Brocade 5424
Brocade 5450
Brocade 5460
Brocade 5470
Brocade 5480
Brocade 7800
Brocade 8000
Brocade VA-40FC
FC8-16, FC8-32, or FC8-48 port blade in the Brocade DCX or DCX-4S platform.
-To preserve the priority level across ISLs, the switches must be running Fabric OS v6.0.0 or
later and must be one of the following platforms: Brocade 300, 4100, 4900, 5000, 5100,
5300, 5410, 5424, 5450, 5480, 7500, 7500E, 7600, 7800, 8000, VA-40FC, 48000,
Brocade DCX, or DCX-4S.
QoS is enabled by default on 8 Gbps ports. QoS is disabled by default on all 4 Gbps ports and
long-distance 8 Gbps ports.

Upgrade considerations for traffic prioritization

This section applies only to 4 Gbps ports and long-distance 8 Gbps ports.