Brocade Fabric OS Administrator's Guide - Supporting Fabric OS v7.0.1 (53-1002446-01, March 2012)
422 Fabric OS Administrator’s Guide
53-1002446-01
QoS zone-based traffic prioritization
21
High, medium, and low priority flows are allocated to different virtual channels (VCs). High priority
flows receive more VCs than medium priority flows, which receive more VCs than low priority flows.
The virtual channels are allocated as shown in Table 74.
NOTE
If there is a single low priority flow to a destination ID (DID) and several medium priority flows to that
same DID, then it is possible that the medium priority flows would have less bandwidth because they
have to share the medium priority VCs, whereas the low priority flow would have a separate VC.
Trunking considerations before you install the Adaptive Networking
license
NOTE
This section applies only to 8 Gbps and 16 Gbps ports that are not long-distance ports.
If ports are part of an active trunk group before the Adaptive Networking license is added, ISLs are
formed without QoS.
When you install the Adaptive Networking license, QoS is automatically enabled on all ports for
which you have not manually disabled QoS, as the ports in the trunk group are set to QoS enabled
by default.
Adding the license does not immediately affect the trunk groups, however. The trunks continue to
operate without QoS until the next time one of the ISLs is toggled, at which point the toggled ISL
comes up with QoS enabled and splits from the trunk group because of a QoS mismatch.
To preserve existing trunk groups, before you install the Adaptive Networking license, manually
disable QoS on these ports, as described next.
Manually disabling QoS on trunked ports
NOTE
QoS is disabled by default on long-distance 8 Gbps and 16 Gbps ports. The following procedure does
not apply to these ports.
1. Connect to the switch and log in using an account with admin permissions.
2. Display the ISL information using the following command:
islshow
TABLE 74 Virtual channels assigned to QoS priority for zone-based prioritization
Priority Number of VCs VCs assigned
High priority 5 10, 11, 12, 13, 14
Medium priority 4 2, 3, 4, 5
Low priority 2 8, 9