Dell MXL 10/40GbE Processing of Data Traffic

Processing of Data Traffic

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.

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.

If FC Flex IO modules are installed, the I/O Aggregator does not perform FIP snooping because the FIP

frames are terminated on the switch for NPIV operations. However, on MXL Switches, you can configure

the switch to operate in FIP Snooping or NPIV mode.

If the MXL 10/40GbE 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. On the Aggregator, if the

FC module is present, the uplink ports are not automatically set up as FCF or bridge ports. The FC Flex

module cannot function as both an NPIV proxy gateway and a FIP snooping bridge at the same time.

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.

1036 FC Flex IO Modules