Dell C1048P Port Extender Networking Configuration Guide for the C9000 Series - Page 575

The following message displays when you enable iSCSI on a switch and describes the configuration changes that are automatically performed: %SYSTEM:CP %IFMGR-5-IFM_ISCSI_ENABLE: iSCSI has been enabled causing flow control to be enabled on all interfaces. EQL detection and enabling iscsi profile-compellent on an interface may cause some automatic configurations to occur like jumbo frames on all ports and no storm control and spanning tree port-fast on the port of detection. You can reconfigure any of the auto-provisioned configuration settings that result when you enable iSCSI on a switch. When you disable the iSCSI feature, iSCSI resources are released and the detection of EqualLogic arrays using LLDP is disabled. Disabling iSCSI does not remove the MTU, flow control, portfast, or storm control configuration applied as a result of enabling iSCSI. NOTE: By default, CAM allocation for iSCSI is set to 0. This disables session monitoring. Synchronizing iSCSI Sessions Learned on VLT-Lags with VLT-Peer The following behavior occurs during synchronization of iSCSI sessions. • If the iSCSI login request packet is received on a port belonging to a VLT lag, the information is synced to the VLT peer and the connection is associated with this interface. • Additional updates to connections (including aging updates) that are learnt on VLT lag members are synced to the peer. • When receiving an iSCSI login request on a non-VLT interface followed by a response from a VLT interface, the session is not synced since it is initially learnt on a non-VLT interface through the request packet. • The peer that sees the login response packet generates a new connection log. If the login response packet uses the ICL path, it is seen by both the peers, which in turn generate logs for this connection. 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. 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) iSCSI Optimization 575