Users Guide

Monitoring iSCSI Traffic Flows
The switch snoops iSCSI session-establishment and termination packets by installing classifier rules that trap iSCSI protocol packets to the
CPU for examination.
Devices that initiate iSCSI sessions usually use well-known TCP ports 3260 or 860 to contact targets. When you enable iSCSI optimization,
by default the switch identifies IP packets to or from these ports as iSCSI traffic.
You can configure the switch to monitor traffic for additional port numbers or a combination of port number and target IP address, and
you can remove the well-known port numbers from monitoring.
Application of Quality of Service to iSCSI Traffic Flows
You can configure iSCSI CoS mode. This mode controls whether CoS (dot1p priority) queue assignment and/or packet marking is
performed on iSCSI traffic.
When you enable iSCSI CoS mode, the CoS policy is applied to iSCSI traffic. When you disable iSCSI CoS mode, iSCSI sessions and
connections are still detected and displayed in the status tables, but no CoS policy is applied to iSCSI traffic.
You can configure whether iSCSI frames are re-marked to contain the configured VLAN priority tag or IP DSCP when forwarded through
the switch.
NOTE: On a switch in which a large proportion of traffic is iSCSI, CoS queue assignments may interfere with other network
control-plane traffic, such as ARP or LACP. Balance preferential treatment of iSCSI traffic against the needs of other critical
data in the network.
Information Monitored in iSCSI Traffic Flows
iSCSI optimization examines the following data in packets and uses the data to track the session and create the classifier entries that
enable QoS treatment.
• Initiator’s IP Address
• Target’s IP Address
• ISID (Initiator defined session identifier)
• Initiator’s IQN (iSCSI qualified name)
• Target’s IQN
• Initiator’s TCP Port
• Target’s TCP Port
• Connection ID
• Aging
• Up Time
If no iSCSI traffic is detected for a session during a user-configurable aging period, the session data is cleared.
If more than 256 simultaneous sessions are logged continuously, the following message displays indicating the queue rate limit has been
reached:
%STKUNIT2-M:CP %iSCSI-5-ISCSI_OPT_MAX_SESS_EXCEEDED: New iSCSI Session Ignored: ISID -
400001370000 InitiatorName - iqn.1991-05.com.microsoft:dt-brcd-cna-2 TargetName -
iqn.2001-05.com.equallogic:4-52aed6-b90d9446c-162466364804fa49-wj-v1 TSIH - 0"
iSCSI Optimization
395