Fibre Channel Interfaces
S e n d d o c u m e n t a t i o n c o m m e n t s t o m d s f e e d b a c k - d o c @ c i s c o . c o m
When a module is removed and replaced with the same type of module, the configuration is retained. If
a different type of module is inserted, then the original configuration is no longer retained.
A brief description of each interface mode follows.
In expansion port (E port) mode, an interface functions as a fabric expansion port. This port may be
connected to another E port to create an Inter-Switch Link (ISL) between two switches. E ports carry
frames between switches for configuration and fabric management. They serve as a conduit between
switches for frames destined to remote N ports and NL ports. E ports support class 2, class 3, and class
An E port connected to another switch may also be configured to form a PortChannel (see
We recommend that you configure E ports on 16-port modules. If you must configure an E port on a
32-port oversubscribed module, then you can only use the first port in a group of four ports (for example,
ports 1 through 4, 5 through 8, and so forth). The other three ports cannot be used.
In fabric port (F port) mode, an interface functions as a fabric port. This port may be connected to a
peripheral device (host or disk) operating as an N port. An F port can be attached to only one N port. F
ports support class 2 and class 3 service.
In fabric loop port (FL port) mode, an interface functions as a fabric loop port. This port may be
connected to one or more NL ports (including FL ports in other switches) to form a public arbitrated
loop. If more than one FL port is detected on the arbitrated loop during initialization, only one FL port
becomes operational and the other FL ports enter nonparticipating mode. FL ports support class 2 and
class 3 service.
FL port mode is not supported on 4-port 10-Gbps switching module interfaces.
An NP port is a port on a device that is in NPV mode and connected to the core switch via a F port. NP
ports behave like N ports except that in addition to providing N port behavior, they also function as
proxies for multiple, physical N ports.
For more details about NP ports and NPV, see
Cisco MDS 9000 Family CLI Configuration Guide
Chapter 13, "Configuring N Port Virtualization."
OL-16184-01, Cisco MDS SAN-OS Release 3.x