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There are different types of Fibre Channel ports, what are they and what type of port does the NetApp filer have?

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Applies to

Data ONTAP 7 and earlier

Question(s) and Answer(s)

There are different types of Fibre Channel ports, what are they and what type of port does the NetApp filer have?

Step

Quick Reference

Short Name Descriptive Name Device Type Port Function
N-port Node Port Node port used to connect a node to a Fibre Chanel switch
F-port Fabric Port Switches Switch port used to connect the Fibre Channel fabric to a node
L-port Loop Port Nodes Node port used to connect a node to a Fibre Channel loop
NL-port Node Loop Nodes Node port which connects to both loops and switches
FL-port Fabric + Loop Port Switches Switch port which connects to both loops and switches
E-port Expansion Port Switches Used to cascade fibre channel switches together
G-port General Port Switches General purpose port which can be configured to emulate other port type
U-port Universal port Switches Intial port state on a switch before anything has connected and it changes personality to an operation state (E-port, F-port, fl-port) or a transitional state like a g-port

Detailed Reference

The filer is an N*_port.

An N_port is a Fibre Channel device (as opposed to switch element) that communicates using the point-to-point link level protocol. It can be attached to either another N_port, or to an F_port.

An NL_port is an FC device (as opposed to switch element) that communicates using the arbitrated loop link level protocol. It can be attached to a set of other NL_ports and at most one FL_port.

An N*_port is a port that may be either an N_port or an NL_port. (note that an NL_port that does not support point-to-point is still considered an N*_port, and an N_port that does not support arbitrated loop is stil considered an N*_port)

Below are explanations of the mediatype for filer ports:

+ p2p: The port can only behave like an N_port, it can't behave like an NL_port
+ loop: The port can only behave like an NL_port, it can't behave like an N_port
+ auto: Depending on the exact behavior of the port on the other end of the link, the filer *might* be able to behave like either an N_port or an NL_port.

Note that there is no standard interoperable definition in fiber channel (FC) for autodetecting topology. This is a vendor specific implementation (by QLogic). Per BURT: 69209, we already know that QLogic's autodetect doesn't interoperate with the Emulex Win2K miniport driver.

An F*_port is a port that may be either an F_port or an FL_port. (note that an FL_port that does not support point-to-point is still considered an F*_port, and an F_port that does not support arbitrated loop is stil considered an F*_port)

Note: that there is additional terminology for ports that must be used as switch-to-switch links (E*_ports) and for ports that may be used as either switch to switch links or can be the port on a fabric that connects to an N*_port (I think these are G*_ports).