Dell PowerEdge M420 Configuration Manual page 451

The following commands show how to configure the iSCSI example depicted
in Figure 16-6.
1 Enable iSCSI optimization on the switch.
console#config
console(config)#iscsi enable
2 Configure the switch to associate the DSCP priority 45 (and the queue
that is mapped to it) with detected iSCSI session traffic. The remark
keyword indicates that the switch should add this priority marking on
packets as it forwards them.
console(config)#iscsi cos dscp 45 remark
console(config)#exit
3 The default target port and IP address criteria is used to determine which
packets are snooped for iSCSI session data (ports 860 and 3260; any IP
address), so no additional commands are required.
Configuring iSCSI Optimization
451