Reference Guide

In an iSCSI session, a switch connects CNA servers (iSCSI initiators) to a storage array (iSCSI targets) in a storage area network (SAN) or
TCP/IP network. iSCSI optimization running on the switch uses dot1p priority-queue assignments to ensure that iSCSI trac receives
priority treatment.
iSCSI conguration notes
• When you enable iSCSI optimization, the switch auto-detects and auto-congures for Dell EqualLogic storage arrays directly connected
to an interface. iSCSI automatically congures switch parameters after connection to a storage device is veried. You must manually
enable an interface to support a storage device that is directly connected to a port, but not automatically detected by iSCSI.
• By default, iSCSI monitoring sessions listen on TCP ports 860 and 3260. Enable iSCSI session monitoring and the aging time for iSCSI
sessions.
• Congure the CoS/DSCP values applied to ingress iSCSI ows — create a class-iscsi class map in POLICY-CLASS-MAP mode.
• iSCSI operation requires LLDP to be enabled. The DCBX application TLV carries information about the dot1p priorities to use when
sending iSCSI trac. This informational TLV is packaged in LLDP PDUs. You can recongure the 802.1p priority bits advertised in the
TLVs.
Congure iSCSI optimization
The iSCSI protocol provides TCP/IP transport of storage trac between servers and storage arrays in a network using iSCSI commands.
1 Congure an interface or interface range to detect a connected storage device.
interface ethernet node/slot/port:[subport]
interface range ethernet node/slot/port:[subport]-node/slot/port[:subport]
2 Enable the interface to support a storage device that is directly connected to the port and not automatically detected by iSCSI. Use
this command for storage devices that do not support LLDP. In this release, the only valid storage-device-name value is
Compellant. The switch auto-detects and auto-congures Dell EqualLogic storage arrays directly connected to an interface when
you enable iSCSI optimization .
iscsi profile-storage storage-device-name
3 Congure DCBX to use LLDP to send iSCSI application TLVs with the dot1p priorities for iSCSI trac in INTERFACE mode.
lldp tlv-select dcbxp-appln iscsi
4 Return to CONFIGURATION mode.
exit
5 (Optional) If necessary, re-congure the iSCSI TCP ports and IP addresses of target storage devices in CONFIGURATION mode.
Separate TCP port numbers with a comma (0-65535; default 860 and 3260).
iscsi target port tcp-port1 [tcp-port2, ..., tcp-port16] [ip-address ip-address]
6 Congure the QoS policy applied to the ingress iSCSI ows. Apply the service policy to ingress interfaces in CONFIGURATION mode.
(Optional) Reset the default CoS dot1p priority (default 4) and/or the trusted DCSP value used for iSCSI trac. Assign an internal
qos-group queue (0 to 7) to dot1p (0 to 7) and DSCP (0 to 63) values in POLICY-CLASS-MAP mode.
class-map type application class-iscsi
policy-map type application policy-iscsi
class class-iscsi
set qos-group
traffic-class-number
set cos dot1p-priority
set dscp dscp-value
end
service-policy type application policy-iscsi
7 Enable iSCSI monitoring sessions on TCP ports in CONFIGURATION mode.
iscsi session-monitoring enable
8 Set the aging time for the length of iSCSI monitoring sessions in CONFIGURATION mode (5 to 43,200 minutes; default 10).
iscsi aging time [minutes]
532
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