Re: iscsi: unsolicited data question

[Priya Viswambharan <priya@npd.hcltech.com>]

Hi Arul,

Unsolicited data can be sent as immediate data or through 
DATA OUT PDUs or both depending on the negotiation done. 

"Immediate unsolicited data only" means that if there is 
unsolicited data to be sent, it can be sent only as 
immediate data - DATA OUT PDUs or combination of immediate 
data and DATA Out for unsolicited data is disallowed in 
this case.

Thanks
Priya

>
> [Arul Ponnusamy] I think "immediate data" implies that it
> is unsolicited. Infact the table in the section 11.12
> says explicitly "Immediate unsolicited data only".
>
>
>  -----Original Message-----
> From: Karthik Selvan [mailto:kselvan@marantinetworks.com]
> Sent: Friday, June 14, 2002 12:46 AM
> To: 'Arul Ponnusamy'; 'Ranganathan, Deva'; 'Julian
> Satran' Cc: ips@ece.cmu.edu
> Subject: RE: iscsi: unsolicited data question
>
>
>
>
>
> Hi,
>         1) I have the same doubt as Deva. i.e Solicited
> mode and unsolicited mode differ only with respect to the
> first outgoing data burst.
>
> Unsolicited mode:
> R2T is not needed only for the first outgoing data burst.
> The subsequent data MUST be solicited.
> Solicited mode:
> all data outs (including the first data out) MUST be
> solicited.
>
> Is this correct?
>
> <karthik>Yes
>
> 2) As per section 9.8 and 11.10, for WRITE operations
> without explicit Initial R2T, the InitialR2T MUST have
> negotiated to NO.
>
>   <karthik> yes
>
>  But as per 11.12 says that if InitialR2T=yes and
> ImmediateData=yes, then Immediate unsolicited data only
> allowed.
>
> <karthik> Draft Section 11.2 clearly says that
> "If ImmediateData is set to Yes and InitialR2t is to
> Yes(default), then only immediate data are accepted in
> the first burst."
>
>  So it is not  ambigous.  (The word "immediate data"
> makes the difference) Please refer previous postings in
> the mailing list. You can get detailed answers.
>
> Hope this helps
> karthik selvan
>
>
>
> -----Original Message-----
> From: Ranganathan, Deva
> [mailto:Deva_Ranganathan@adaptec.com] Sent: Thursday,
> June 13, 2002 6:59 PM
> To: 'Julian Satran'
> Cc: ips@ece.cmu.edu
> Subject: RE: iscsi: unsolicited data question
>
>
> "tells me that a target, at all times during a data
> sequence transfer, can be
>
> one or the other, but not both (non R2T for the initial
> data out, R2T for the
> remaining data).  Is this correct?"
>
> really? I thought thatit is permissible to have non-R2T
> for the initial data out and R2T for
> remaining. i.e for a 64K transfer, the first 32K can be
> the first burst size of data and
> the next 32K will be solicited by the target through R2T.
> Am I missing something?
>
>
> -Deva
>
>
>
> -----Original Message-----
> From: Julian Satran [mailto:Julian_Satran@il.ibm.com]
> Sent: Wednesday, June 12, 2002 6:05 AM
> To: Dennis Young
> Cc: ips@ece.cmu.edu; owner-ips@ece.cmu.edu
> Subject: Re: iscsi: unsolicited data question
>
>
>
> yes - julo
>
>
>
> 	Dennis Young <dyoung@rhapsodynetworks.com>
> Sent by: owner-ips@ece.cmu.edu
>
>
> 06/12/2002 06:20 AM
> Please respond to Dennis Young
>
>
>
>         To:        ips@ece.cmu.edu
>         cc:
>         Subject:        iscsi: unsolicited data question
>
>
>
>
> I have a question which has been asked before, but I
> couldn't find a direct answer in the archive.  The table
> on page 200 of draft 12 doesn't directly answer this
> question either.
>
> The first paragraph on page 36 of draft 12 says "Targets
> operate in either solicitied (R2T) data mode or
> unsolicited (non R2T) data mode." tells me that a target,
> at all times during a data sequence transfer, can be
>
> one or the other, but not both (non R2T for the initial
> data out, R2T for the
> remaining data).  Is this correct?
>
> Thanks,
> Dennis
>
> ---snip from an old email dated 3/30/2001---
>
> " Hi Julian
> Sorry if I'm covering old ground... Is it possible to use
> unsolicited data for the first burst and then request any
> remaining data using R2T? For example, if the target has
> a previously allocated buffer available (length defined
> by FirstBurstSize) for unsolicited data, then once the
> initiator has sent unsolicited data up to and including
> this amount then the remaining data (if any) can be
> requested using R2T once the target has the buffer space
> available.
> ...Matthew Burbridge Hewlett Packard, Bristol Telnet: 312
> 7010 E-mail: matthewb@bri.hp.com "

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