Administrator Guide

• If you congured ow-control, iSCSI uses the current conguration. If you did not congure ow-control, iSCSI auto-congures ow
control.
• iSCSI monitoring sessions — the switch monitors and tracks active iSCSI sessions in connections on the switch, including port
information and iSCSI session information.
• iSCSI QoS — A user-congured iSCSI class of service (CoS) prole is applied to all iSCSI trac. Classier rules are used to direct the
iSCSI data trac to queues that can be given preferential QoS treatment over other data passing through the switch. Preferential
treatment helps to avoid session interruptions during times of congestion that would otherwise cause dropped iSCSI packets.
• iSCSI DCBx TLVs are supported.
The following gure shows iSCSI optimization between servers in a server enclosure and a storage array in which an Aggregator connects
installed servers (iSCSI initiators) to a storage array (iSCSI targets) in a SAN network. iSCSI optimization running on the Aggregator is
congured to use dot1p priority-queue assignments to ensure that iSCSI trac in these sessions receives priority treatment when
forwarded on Aggregator hardware.
Figure 59. iSCSI Optimization Example
Monitoring iSCSI Trac Flows
The switch snoops iSCSI session-establishment and termination packets by installing classier 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 identies IP packets to or from these ports as iSCSI trac.
iSCSI Optimization
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