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.

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