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?
|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|
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).