RE: A couple of iFCP questions

[Black_David@emc.com]

> I need to correct my prior message to state that "It is safe to discard
> a translation when there are no N_PORT sessions to the remote N_PORT...".
> The translation MAY be discarded when a PLOGO logout message
> that terminates the N_PORT session is detected.  This is what I meant
> in the original message.  Sorry about the confusion.

And I was a little sloppy in my language.  By "dropping the N_PORT session",
I meant the use of PLOGO to terminate the session.  After doing this, a
Fibre Channel device can use PLOGI to initiate a new connection to the same
target without checking with the fabric nameserver, because it can rely on
state change notification to tell it if a N_PORT ID has become invalid;
there
are FC devices that behave in this fashion.  Probing a remote N_PORT
to see if a session is alive won't catch this situation; something like a
state change notification to force the originator to go back to the fabric
nameserver is necessary.  Reliance on state change notification is also
why the WWPN of the target may not be checked when the new session
is set up.

In any case, this is further down in the details than I really wanted to go
at
this juncture -- I'm satisfied that FC state change notifications can be
used to handle these situations.  The result may have some
"brute force" characteristics to it, and the usual caveats about not
using state change notifications unless they're really necessary applies.

--David
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David L. Black, Senior Technologist
EMC Corporation, 42 South St., Hopkinton, MA  01748
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black_david@emc.com       Mobile: +1 (978) 394-7754
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