RE: ISCSI: Login Parameters - Defaults?

[Black_David@emc.com]

Kevin,

Part of what's going on here is that a robust implementation
minimizes assumptions about what the other party to the communication
will do - this is part of the usual IETF admonition to be
conservative in what is sent and liberal in what is accepted.
If the default value is for convenience/preference and your
implementation can cope if the other side happens to use a different
default, then there's no need to negotiate that key.  OTOH, if us
of the default is important to your implementation for some reason,
it is incumbent upon you to negotiate it.  It is not robust
to assume that the other side will use the default in the absence
of negotiation and then complain that it's the other implementation's
fault that things went wrong when it didn't use the specified
default -- it was your responsibility to negotiate the key if
you cared about its value.  Yes, this results in potentially
verbose negotiations, but it reduces the possibility for confusion
about what's supposed to happen as a result.

Thanks,
--David

-----Original Message-----
From: Julian Satran [mailto:Julian_Satran@il.ibm.com]
Sent: Thursday, April 25, 2002 3:33 PM
To: LEMAY,KEVIN (A-Roseville,ex1)
Cc: ips@ece.cmu.edu
Subject: RE: ISCSI: Login Parameters - Defaults?



I am trying again - If you are happy with the dafualt don't do anything. If
you want to change it you must negotiate - not just answer to an implied
offer. 

Julo 


"LEMAY,KEVIN (A-Roseville,ex1)" <kevin_lemay@agilent.com> 
04/25/2002 10:04 PM 
Please respond to "LEMAY,KEVIN (A-Roseville,ex1)" 
        
        To:        Julian Satran/Haifa/IBM@IBMIL 
        cc:        ips@ece.cmu.edu 
        Subject:        RE: ISCSI: Login Parameters - Defaults? 

       


Julian,

But defaults are an implicit offer. If I do not offer the key the I am
assuming the default.

Can you re-word the sentence to incorporate what you just explained in the
e-mail... This is much clearer, at least to me.

Kevin


-----Original Message-----
From: Julian Satran [mailto:Julian_Satran@il.ibm.com]
Sent: Thursday, April 25, 2002 11:47 AM
To: LEMAY,KEVIN (A-Roseville,ex1)
Cc: ips@ece.cmu.edu
Subject: Re: ISCSI: Login Parameters - Defaults?



It means only that regardless of the fact that a default is available if you
state first a key=value you are the originator and the other party MUST
respond unless specified otherwise (as in booleans). In other words there is
no such think as an implicit offer of the current or default value. 

Julo 



                "LEMAY,KEVIN (A-Roseville,ex1)" <kevin_lemay@agilent.com> 


04/25/2002 07:01 PM 
Please respond to "LEMAY,KEVIN (A-Roseville,ex1)" 


       
       To:        Julian Satran/Haifa/IBM@IBMIL 
       cc:        ips@ece.cmu.edu 
       Subject:        ISCSI: Login Parameters - Defaults? 

      


Page 64 in iSCSI v12 says,

"All negotiations are stateless and explicit (i.e., the result MUST be
based only on newly exchanged values). There is no such thing as implicit
offers. If an explicit offer is not made then a reply cannot be expected."

It is unclear to me how this is supposed to work. Does this mean that I must
negotiate every key pair? This is confusing because chapter 11 still
contains default values.

If I do not negotiate a parameter, is it assumed to be set at the default or
must I negotiate every parameter ?

If I must negotiate every parameter, then the "default" value should be
removed or renamed to "suggested setting".

Thanks,

Kevin Lemay