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

Consider a sample scenario of NPG operation. An FX2 server chassis configured as an NPG does not join a SAN fabric, but functions as an FCoE-FC bridge that forwards storage traffic between servers and core SAN switches. The core switches forward SAN traffic to and from FC storage arrays.

An FX2 chassis FC port is configured as an N (node) port that logs in to an F (fabric) port on the upstream FC core switch and creates a channel for N-port identifier virtualization. NPIV allows multiple N-port fabric logins at the same time on a single, physical Fibre Channel link.

Converged Network Adapter (CNA) ports on servers connect to the FX2 chassis Ten-Gigabit Ethernet ports and log in to an upstream FC core switch through the N port. Server fabric login (FLOGI) requests are converted into fabric discovery (FDISC) requests before being forwarded to the FC core switch.

Servers use CNA ports to connect over FCoE to an Ethernet port in ENode mode on the NPIV proxy gateway. FCoE transit with FIP snooping is automatically enabled and configured on the FX2 gateway to prevent unauthorized access and data transmission to the SAN network. FIP is used by server CNAs to discover an FCoE switch operating as an FCoE forwarder (FCF).

The NPIV proxy gateway aggregates multiple locally connected server CNA ports into one or more upstream N port links, conserving the number of ports required on an upstream FC core switch while providing an FCoE-to-FC bridging functionality. The upstream N ports on an FX2 can connect to the same or multiple fabrics.

Using an FCoE map applied to downstream (server-facing) Ethernet ports and upstream (fabric-facing) FC ports, you can configure the association between a SAN fabric and the FCoE VLAN that connects servers over the NPIV proxy gateway to FC switches in the fabric. An FCoE map virtualizes the upstream SAN fabric as an FCF to downstream CNA ports on FCoE-enabled servers as follows:

• As soon as an FC N port comes online ( no shutdown command), the NPG starts sending FIP multicast advertisements, which contain the fabric name derived from the 64-bit worldwide name (WWN) of the principal SAN switch. (The principal switch in a fabric is the FC switch with the lowest domain ID.)
• When you apply the FCoE map to a server-facing Ethernet port in ENode mode, ACLs are automatically configured to allow only FCoE traffic from servers that perform a successful FLOGI on the FC switch. All other traffic on the VLAN is denied.

You can specify one or more upstream N ports in an FCoE map. The FCoE map also contains the VLAN ID of the dedicated VLAN used to transmit FCoE traffic between the SAN fabric and servers.

The Aggregator with the NPG provides the following protocol services:

• Fibre Channel service to create N ports and log in to an upstream FC switch.
• FCoE service to perform:
  • Virtualization of FC N ports on an NPG so that they appear as FCoE FCFs to downstream servers.
  • NPIV service to perform the association and aggregation of FCoE servers to upstream F ports on core switches (through N ports on the NPG). Conversion of server FLOGIs and FDISCs, which are received over the Aggregator with the ENode ports, are converted into FDISCs addressed to the upstream F ports on core switches.

The Aggregator with the NPG provides the following functionality in a storage area network:

• FIP Snooping bridge that provides security for FCoE traffic using ACLs.
• FCoE gateway that provides FCoE-to-FC bridging. N-port virtualization using FCoE maps exposes upstream F ports as FCF ports to downstream server-facing ENode ports on the NPG.

The following table describes the terms used in an NPG configuration on the Aggregator.

DCB Maps

A Data Center Bridging (DCB) map is used to configure DCB functionality, such as PFC and ETS, on the Aggregator with the Ethernet ports that support CEE traffic and are DCBx-enabled, by default.

By default, no PFC and ETS settings in a DCB map are applied to the Aggregator with the Ethernet ports when they are enabled. On an Aggregator with the NPG, you must configure PFC and ETS parameters in a DCB map and then apply the map to server-facing Ethernet ports.

FCoE Maps

An FCoE map is used to identify the SAN fabric to which FCoE storage traffic is sent. Using an FCoE map, an Aggregator with the NPG operates as an FCoE-FC bridge between an FC SAN and FCoE network by providing FCoE-enabled servers and switches with the necessary parameters to log in to a SAN fabric.

An FCoE map applies the following parameters on server-facing Ethernet and fabric-facing FC ports on the Aggregator:

• The dedicated FCoE VLAN used to transport FCoE storage traffic.
• The FC-MAP value used to generate a fabric-provided MAC address.
• The association between the FCoE VLAN ID and FC fabric ID where the desired storage arrays are installed. Each Fibre Channel fabric serves as an isolated SAN topology within the same physical network.
• The priority used by a server to select an upstream FCoE forwarder (FCF priority).
• FIP keepalive (FKA) advertisement timeout.

When you configure an Aggregator with the NPG, FCoE transit with FIP snooping is automatically enabled and configured using the parameters in the FCoE map applied to server-facing Ethernet and fabric-facing FC interfaces.

After you apply an FCoE map on an FC port, when you enable the port ( no shutdown), the NPG starts sending FIP multicast advertisements on behalf of the FC port to downstream servers in order to advertise the availability of a new FCF port on the FCoE VLAN. The FIP advertisement also contains a keepalive message to maintain connectivity between a SAN fabric and downstream servers.