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

Fibre Channel networks used for SAN traffic employ switches that operate as trusted devices. End devices log into the switch to which they are attached in order to communicate with the other end devices attached to the Fibre Channel network. Because Fibre Channel links are point-to-point, a Fibre Channel switch controls all storage traffic that an end device sends and receives over the network. As a result, the switch can enforce zoning configurations, ensure that end devices use their assigned addresses, and secure the network from unauthorized access and denial-of-service attacks.

To ensure similar Fibre Channel robustness and security with FCoE in an Ethernet cloud network, the Fibre Channel over Ethernet initialization protocol (FIP) establishes virtual point-to-point links between FCoE end-devices (server ENodes and target storage devices) and FCoE forwarders (FCFs) over transit FCoE-enabled bridges.

Ethernet bridges commonly provide access control list (ACLs) that can emulate a point-to-point link by providing the traffic enforcement required to create a Fibre Channel-level of robustness. In addition, FIP serves as a Layer 2 protocol to:

• Operate between FCoE end-devices and FCFs over intermediate Ethernet bridges to prevent unauthorized access to the network and achieve the required security.
• Allow transit Ethernet bridges to efficiently monitor FIP frames passing between FCoE end-devices and an FCF, and use the FIP snooping data to dynamically configure ACLs on the bridge to only permit traffic authorized by the FCF.

FIP enables FCoE devices to discover one another, initialize and maintain virtual links over an Ethernet network, and access storage devices in a storage area network. FIP satisfies the Fibre Channel requirement for point-to-point connections by creating a unique virtual link for each connection between an FCoE end-device and an FCF via a transit switch.

FIP provides a functionality for discovering and logging in to an FCF. After discovering and logging in, FIP allows FCoE traffic to be sent and received between FCoE end-devices (ENodes) and the FCF. FIP uses its own EtherType and frame format. The below illustration about FIP discovery, depicts the communication that occurs between an ENode server and an FCoE switch (FCF).

FIP performs the following functions:

• FIP virtual local area network (VLAN) discovery: FCoE devices (Enodes) discover the FCoE VLANs on which to transmit and receive FIP and FCoE traffic.
• FIP discovery: FCoE end-devices and FCFs are automatically discovered.
• Initialization: FCoE devices perform fabric login (FLOGI) and fabric discovery (FDISC) to create a virtual link with an FCoE switch.
• Maintenance: A valid virtual link between an FCoE device and an FCoE switch is maintained and the link termination logout (LOGO) functions properly.

Figure 1. FIP Discovery and Login between an ENode and an FCF