Re: iscsi : query based login negotiation.

[Sandeep Joshi <sandeepj@research.bell-labs.com>]

Another alternative is to let the the initiator send 
"DataPDULength=0".  The target can then select & send
a lower value it prefers.

See Appendix D
  A value of 0 indicates no limit (the largest possible number)

This would work for DataPDULength, MaxBurst and FirstBurst.

-Sandeep

Santosh Rao wrote:
> 
> Julian,
> 
> I have another question on the subject of login negotiation, which was
> brought up earlier in a previous mail. I've enclosed the mail below
> [with irrelevant portions snipped out.]
> 
> Could you please clarify if the below described behaviour is possible ?
> 
> Thanks,
> Santosh
> 
> Santosh Rao wrote:
> >
> > Julian,
> >
> > Another value-add of the "responder picks the negotiation result model"
> > is that the initiator can use the following "query based" negotiation
> > model to always use the values the target is capable of offering :
> >
> > I -> T : DataPDULength=?
> > T -> I : DataPDULength=64K
> >
> > Both sides agree to use a DataPDULength of 64K.
> 
> > I suggest that we allow the above "query based model", since this is
> > more efficient to use when an initiator has no key limitations and would
> > like to use the value a target can offer. In order to allow the "query
> > based model", you would need to state in the draft that a key value of
> > "?" over-rides the default, implying the target offered value would be
> > the result of the negotiation.
> >
> > In particular, the "query based model" is quite useful when an initiator
> > wishes to function with the target's maximal supported values for keys
> > like DataPDULength, FirstBurstSize, MaxBurstSize, MaxOutStandingR2T,
> > LogoutLoginMinTime, LogoutLoginMaxTime, etc without expressing any
> > limitations on its own key value.
> >
> > Comments ?
> >
> > Thanks,
> > Santosh
> 
> --
> ##################################
> Santosh Rao
> Software Design Engineer,
> HP-UX iSCSI Driver Team,
> Hewlett Packard, Cupertino.
> email : santoshr@cup.hp.com
> Phone : 408-447-3751
> ##################################