ethernet and switches, was Re: [rescue] Mozilla Firefox
swl at catbert.net
Sat Apr 24 15:48:00 CDT 2004
On Apr 23, 2004, at 10:09 PM, ghub005 wrote:
> If on the other hand you're wondering why I used an older loop based
> like 'FC-AL' to refer to a switched SAN topology
I've heard from various sources that switched FC actually preceded
FC-AL, but I think FC-AL may have been standardized by ANSI first.
Now, for the pedantry:
> every link between the switch and the HBA is a loop.
Most links between HBAs and switches are actually point-to-point, with
the HBA port acting as an N_Port (node) and the switch port acting as
an F_Port (fabric). If the link was a loop, the HBA would be an
NL_Port and the switch port would be an FL_Port.
> The terms 'fibre channel switch' and 'FC-AL switch' are the same thing.
Not necessarily, since not all switches support FC-AL. FL_Port (fabric
loop) switch ports can support loop devices (such as older FC tape
drives); F_Port (fabric mode) switch ports only support point-to-point
connections. Most switches will automatically detect loop devices and
change the port to FL_Port, but some (like McData's Intrepid 6064) do
not support FL_Port, so an intermediary switch or gateway is required.
Scotty Logan <scotty at catbert.net>
Never take life seriously - Nobody gets out alive anyway
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