Command Line Interface Guide

552 iSCSI Optimization Commands
Parameter Description
Default Configuration
By default, frames are not remarked. The default vpt setting for iSCSI is 4,
which the default classofservice dot1p mapping assigns to queue 2.
Command Mode
Global Configuration mode.
User Guidelines
The remark option only applies to DSCP values. Remarking is not available
for vpt values.
By default, iSCSI flows are assigned to the highest VPT/DSCP value that is
mapped to the highest queue not used for stack management or the voice
VLAN. Make sure you configure the relevant Class of Service parameters for
the queue in order to complete the setting.
Configuring the VPT/DSCP value sets the QoS profile which selects the
egress queue to which the frame is mapped. The default setting for egress
queues scheduling is Weighted Round Robin (WRR).
You may alter the QoS setting by configuring the relevant ports to work in
other scheduling and queue management modes via the Class of Service
settings. These choices may include strict priority for the queue used for
iSCSI traffic. The downside of strict priority is that, in certain circumstances
Parameter Description
enable Enables application of preferential QoS treatment to iSCSI
frames.
disable Disables application of preferential QoS treatment to iSCSI
frames.
vpt/dscp The VLAN Priority Tag or DSCP value to assign received iSCSI
session packets.
remark Mark the iSCSI frames with the configured DSCP when
egressing the switch.
2CSPC4.XModular-SWUM201.book Page 552 Monday, October 3, 2011 2:21 PM