Dell PowerEdge FN I/O Module Configuration Guide 9.10(0.0)

The Dell Networking OS determines the module type that is plugged into the slot. Based on the module type, the software performs the appropriate tasks. The FC Flex IO module encapsulates and decapsulates the FCoE frames. The module directly switches any non-FCoE or non-FIP traffic, and only FCoE frames are processed and transmitted out of the Ethernet network.

When the external device sends FCoE data frames to the switch that contains the FC Flex IO module, the destination MAC address represents one of the Ethernet MAC addresses assigned to FC ports. Based on the destination address, the FCoE header is removed from the incoming packet and the FC frame is transmitted out of the FC port. The flow control mechanism is performed using per-priority flow control to ensure that frame loss does not occur owing to congestion of frames.

Operation of the FIP Application

The NPIV proxy gateway terminates the FIP sessions and responses to FIP messages. The FIP packets are intercepted by the FC Flex IO module and sent to the Dell Networking OS for further analysis. The FIP application responds to the FIP VLAN discovery request from the host based on the configured FCoE VLANs. For every ENode and VN_Port that is logged in, the FIP application responds to keepalive messages for the virtual channel. If the FC link becomes inactive or a logging off of the switch occurs, the FIP engine sends clear virtual link (CVL) messages to the host. The FIP application also responds to solicited advertisements from the end-device. In addition, the FIP application periodically sends advertisement packets to the end-devices for each FCF that is part of the NPIV proxy gateway.

On FN IOM switches, you can configure the switch to operate in FIP Snooping or NPIV mode.

If the FN IOM Switch functions in the NPIV mode and you attempt to set the uplink port to be an FCF or a bridge port, a warning message displays and the settings are not saved.

Operation of the NPIV Proxy Gateway

The NPIV application on the FC Flex IO module manages the FC functionalities configured in Dell Networking OS. After the FC link comes up, the gateway sends the initial FLOGI request to the connected switch using the switch and port WWN methods. After a successful login, the NPIV gateway sends a notification to inform the CNA that the FCF available to log in. The source address of the FIP advertisement and FIP discovery advertisement response contain the MAC address of the FC Flex IO module port. Depending on the number of login sessions on a particular FCF, the NPIV gateway can load-balance the login sessions from ENodes.

The NPIV application performs the FLOGI to FDISC conversion and sends the new FC frame on the associated FC ports. After the external switch responds to the FLOGI request, the NPIV gateway establishes the NPIV session and sends the frame to the FIP application. The FIP application establishes virtual links to convert FCoE FLOGI accept messages into FIP FLOGI accept messages. The corresponding ACL for the accept message is then applied. If a FIP timeout from ENode or VN_PORT occurs, the NPIV application performs the FC fabric logout to the external FC switch. The NPIV application manages the sessions between the FCoE and the FC domain.