Brocade FICON Administrator’s Guide (Supporting Fabric OS v7.3.0) - Manual (Page 50)

frame header. High, medium, and low priority frames are allocated to different virtual channels (VCs).
High priority frames receive more VCs than medium priority frames, which receive more VCs than low
priority frames. The virtual channels are allocated according to the CS_CTL value.
NOTE
Check with your host and storage manufacturer to determine if they support Fibre Channel CS_CTL
prioritization on their devices.
The Fabric OS Administrator's Guide provides additional information on this feature and steps to
enable CS_CTL-based frame prioritization on your switch using the portCfgQos command.
The configureChassis command allows you to set chassis-level configuration parameters, such as
cfgload, custom, system, and Fabric OS attributes, to be used by ASIC drivers. The following
procedure uses the Fabric OS attribute, CS_CTL QoS Mode, to change CS_CTL values mapped to
VCs for priority levels from default to auto mode. While default mode maps CS_CTL values 1-8 (low),
9-16 (medium), and 17-24 (high) to specific VCs, auto mode maps CS_CTL values 1 (low), 2
(medium), and 3 (high) to VCs based on the ASIC supported by your platform. For DCX 8510-4, DCX
8510-8, and 6510 models, a single CS_CTL value is mapped to multiple VCs.
To enable auto mode for CS_CTL to VC mapping on a FICON switch, use the following steps.
NOTE
This process is disruptive as you must reboot the chassis to reset the configuration in the ASIC. You
cannot enable CS_CTL mapping on individual ports until this is done. If auto mode is selected, you
must select auto mode for each chassis in the fabric. Not doing so will mean different virtual channels
(VCs) will be used across the fabric with undesirable results.
1. Connect to the switch and log in to an account that has admin permissions.
2. Launch the configureChassis command.
3. Select no when prompted to modify cfgload attributes, custom attributes, and system attributes,
then select yes to modify Fabric OS attributes.
root> configurechassis
Configure...
cfgload attributes (yes, y, no, n): [no]
Custom attributes (yes, y, no, n): [no]
system attributes (yes, y, no, n): [no]
fos attributes (yes, y, no, n): [no] y
4. Select 1 (auto mode) when prompted to configure CS_CTL QoS mode.
CSCTL QoS Mode (0 = default; 1 = auto mode): (0..1) [0] 1
5. Reboot the switch or chassis.
6. To verify if auto mode or default mode is set for the chassis, enter the configShow --all
command.
root> configshow -all | grep fos.csctlMode
fos.csctlMode:1
• If auto mode is set, the following should display in the command output:
fos.csctlMode:1
• If default mode is set, the following should display in the command output:
fos.csctlMode:0
To return to default mode, follow the preceding steps, but select 0 (default mode) for CS_CTL
QoS mode when modifying fos attributes through the configureChassis command.
Administering FICON Fabrics
48 FICON Administrator's Guide
53-1003144-01