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 the iSCSI optimization feature uses the VLAN priority or IP DSCP mapping to
determine the traffic class queue. By default, iSCSI flows are assigned to dot1p priority 4. To map incoming
iSCSI traffic on an interface to a dot1p priority-queue other than 4, use the
QoS dot1p-priority
command
(refer to
QoS dot1p Traffic Classification and Queue Assignment
). Dell Networking recommends setting the
CoS dot1p priority-queue to 0 (zero).
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 -
iSCSI Optimization
545
Summary of Contents for S4048T
Page 1: ...Dell Configuration Guide for the S4048T ON System 9 10 0 1 ...
Page 98: ... saveenv 7 Reload the system uBoot mode reset Management 98 ...
Page 113: ...Total CFM Pkts 10303 CCM Pkts 0 LBM Pkts 0 LTM Pkts 3 LBR Pkts 0 LTR Pkts 0 802 1ag 113 ...
Page 411: ...mode transit no disable Force10 Resilient Ring Protocol FRRP 411 ...
Page 590: ...Figure 67 Inspecting the LAG Configuration Link Aggregation Control Protocol LACP 590 ...
Page 646: ...Figure 87 Configuring Interfaces for MSDP Multicast Source Discovery Protocol MSDP 646 ...
Page 647: ...Figure 88 Configuring OSPF and BGP for MSDP Multicast Source Discovery Protocol MSDP 647 ...
Page 653: ...Figure 91 MSDP Default Peer Scenario 2 Multicast Source Discovery Protocol MSDP 653 ...
Page 654: ...Figure 92 MSDP Default Peer Scenario 3 Multicast Source Discovery Protocol MSDP 654 ...
Page 955: ...Figure 119 Single and Double Tag First byte TPID Match Service Provider Bridging 955 ...