This command sets the quality of service profile that will be applied to iSCSI flows. iSCSI flows are assigned by default to the highest VPT/DSCP mapped to the highest queue not used for stack management. The user should also take care of configuring the relevant Class of Service parameters for the queue in order to complete the setting.
Setting the VPT/DSCP sets the QoS profile which determines the egress queue to which the frame is mapped. The switch default setting for egress queues scheduling is Weighted Round Robin (WRR).
You may complete the QoS setting by configuring the relevant ports to work in other scheduling and queue management modes via the Class of Service settings. Depending on the platform, these choices may include strict priority for the queue used for iSCSI traffic. The downside of strict priority is that, in certain circumstances (under heavy high priority traffic), other lower priority traffic may get starved. In WRR the queue to which the flow is assigned to can be set to get the required percentage.
| Format | iscsi cos {vpt vpt | dscp dscp} [remark] |
| Mode | Global Config |
| Parameter | Description |
|---|---|
| vpt/dscp | The VLAN Priority Tag or DSCP to assign iSCSI session packets. |
| remark | Mark the iSCSI frames with the configured VPT/DSCP when egressing the switch. |
Example: The following example sets the quality of service profile that will be applied to iSCSI flows.
(switch)(config)#iscsi cos vpt 5 remark
