RE: ips : Is FirstBurstSize valid when InitialR2T=yes ?

[Eddy Quicksall <Eddy_Quicksall@ivivity.com>]

Draft 10 says:

FirstBurstSize=<number-512-to-(2**24-1)>

So that means you can't send a 0, doesn't it?

Eddy

-----Original Message-----
From: Santosh Rao [mailto:santoshr@cup.hp.com]
Sent: Wednesday, February 06, 2002 3:01 PM
To: Fischer, Michael
Cc: 'Eddy Quicksall'; IPS Reflector
Subject: Re: ips : Is FirstBurstSize valid when InitialR2T=yes ?


IMO, the FirstBurstSize key value negotiated during login is a don't
care if *BOTH* immediate data and un-solicited data have been disabled.

However, if the target knows up-front that it does not support either
immediate or un-solcited and it receives the key FirstBurstSize during
login negotiation, it should return a 0 value as the result of the
negotiation for FirstBurstSize.

(Note that the special semantics of 0 implying no limit is no longer
true for FirstBurstSize and hence, the target can just return 0 iff both
immediata data and un-solicited data are disabled in login negotiation.)

- Santosh


"Fischer, Michael" wrote:
>
> What if the sequence is as follows:
>
> I->T    FirstBurstSize=512; T=0; NSG=CSG;
> T->I    FirstBurstSize=512; T=0; NSG=CSG;
> I->T    InitialR2T=no, ImmediateData=no; T=1; NSG=FULL
>
> If the target does not support InitialR2T=no..  Does login now fail?
There
> does not seem to be a way for the target to say that it requires R2T.  Why
> did the Initiator send FirstBurstSize if it was setting InitialR2T to no?
> There is no negotiation with an AND function.
>
> Michael Fischer
>
> -----Original Message-----
> From: Eddy Quicksall [mailto:Eddy_Quicksall@ivivity.com]
> Sent: Wednesday, February 06, 2002 9:47 AM
> To: Santosh Rao; IPS Reflector
> Subject: RE: ips : Is FirstBurstSize valid when InitialR2T=yes ?
>
> That is how I am interpreting it.
>
> BTW: How about this one ...
>
> I->T FirstBurstSize=512, InitialR2T=no, ImmediateData=no
>
> If the target does not support InitialR2T=no, how should it respond to
> FirstBurstSize?
>
> Should the target do this (for draft >= 9)?
>
> T->I FirstBurstSize=irrelevant, InitialR2T=yes, ImmediateData=no
>
> Eddy
>
> -----Original Message-----
> From: Santosh Rao [mailto:santoshr@cup.hp.com]
> Sent: Tuesday, February 05, 2002 2:56 PM
> To: IPS Reflector
> Subject: ips : Is FirstBurstSize valid when InitialR2T=yes ?
>
> Hello,
>
> Can someone clarify if the login key FirstBurstSize is valid when :
> InitialR2T=yes  and ImmediateData=yes ?
>
> i.e. if immediate data is enabled and un-solicited data is disabled
> during login negotiation, is the value of FirstBurstSize received in the
> login response to be interpreted ?
>
> My current understanding is that FirstBurstSize is inclusive of the
> immediate data portion, and so, if immediate data is enabled, but
> un-solicited data is disabled, then, FirstBurstSize *must* be valid and
> must be <= DataPDULength. (after rev 09, it would be <=
> (MaxRecvPDULength - the header components size)).
>
> For example, a target implementation may offer a FirstBurstSize <
> DataPDULength, in which case, the immediate data size is the
> MIN(DataPDULength, FirstBurstSize, bytes_to_send).
>
> Can someone clarify if this is a correct interpretation or set me right
> on this ?
>
> Thanks,
> Santosh
>
> --
> ##################################
> Santosh Rao
> Software Design Engineer,
> HP-UX iSCSI Driver Team,
> Hewlett Packard, Cupertino.
> email : santoshr@cup.hp.com
> Phone : 408-447-3751
> ##################################

--
##################################
Santosh Rao
Software Design Engineer,
HP-UX iSCSI Driver Team,
Hewlett Packard, Cupertino.
email : santoshr@cup.hp.com
Phone : 408-447-3751
##################################