White Papers

NPIV Proxy Gateway Operations and Capabilities
Benefits of an NPIV Proxy Gateway
The FN IOM with the FC Flex IO module functions as a top-of-rack edge switch that supports Converged Enhanced Ethernet
(CEE) traffic — FCoE for storage, Interprocess Communication (IPC) for servers, and Ethernet LAN (IP cloud) for data — as
well as Fibre Channel (FC) links to one or more SAN fabrics.
Using an NPIV proxy gateway (NPG) helps resolve the following problems in a storage area network:
● Fibre Channel storage networks typically consist of servers connected to edge switches, which are connected to SAN core
switches. As the SAN grows, it is necessary to add more ports and SAN switches. This results in an increase in the required
domain IDs, which may surpass the upper limit of 239 domain IDs supported in the SAN network. An NPG avoids the need
for additional domain IDs because it is deployed outside the SAN and uses the domain IDs of core switches in its FCoE links.
● With the introduction of 10GbE links, FCoE is being implemented for server connections to optimize performance. However,
a SAN traditionally uses Fibre Channel to transmit storage traffic. FCoE servers require an efficient and scalable bridging
feature to access FC storage arrays, which an NPG provides.
NPIV Proxy Gateway Operation
Consider a sample scenario of NPG operation. An M1000e 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 M1000e 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 M1000e chassis Ten-Gigabit Ethernet ports and log in to an
upstream FC core switch through the FC Flex IO module N port. Server fabric login (FLOGI) requests are converted into fabric
discovery (FDISC) requests before being forwarded by the FC Flex IO module 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 M1000e gateway to prevent unauthorized access and data
transmission to the SAN network (see FCoE Transit). 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 M1000e 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.
NPIV Proxy Gateway: Protocol Services
The FN IOM with the FC Flex IO module 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.
FC Flex IO Modules
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