iSCSI : Status SNACK mandatory ?

[Santosh Rao <santoshr@cup.hp.com>]

Rev 06 seems to indicate that Status SNACK is still mandatory (?). 

I thought the group had consensus that Status SNACK recovery must not be
mandated and Julian had agreed to make it optional. (See
http://ips.pdl.cs.cmu.edu/mail/msg04008.html).

The following text in rev 06 seems to indicate that target support for
Status SNACK is still mandatory :

Section 2.16
"iSCSI targets MUST support Status SNACK and MAY support Data SNACK."

Section 6.7.2 :
"The initiator MAY request the missing responses through SNACK, in which
case the target MUST reissue them."

Some clarifications on whether SNACK recovery schemes are going to be
optional would be helpful.

- Santosh



Ayman Ghanem wrote:
> 
> Is Status SNACK reject going to be added as a reason for a reject PDU?. If
> not, what is the appropriate behavior on a target receiving a status SNACK
> that it can not fulfill?. Should it terminate the connection?.
> 
> -Ayman
> 
> > -----Original Message-----
> > From: owner-ips@ece.cmu.edu [mailto:owner-ips@ece.cmu.edu]On Behalf Of
> > julian_satran@il.ibm.com
> > Sent: Friday, April 27, 2001 4:59 AM
> > To: ips@ece.cmu.edu
> > Subject: Re: iSCSI : target session login behaviour
> >
> >
> >
> >
> > SNACK rejected has been removed from the SCSI Response - Julo

> > Steph,
> >
> > The iSCSI draft is unclear today about the exact mechanism through which
> > the target indicates "invalid parameters" in response to a received
> > command.
> >
> > 1) Should it use a REJECT PDU or respond with the appropriate response
> > for that PDU indicating a response code of "Invalid Parameters" and a
> > "first bad byte" offset that indicates which parameter the target
> > disliked.
> >
> > IMO, an "Invalid Parameters" response in the response codes is
> > appropriate for SCSI Command and SCSI Task Mgmt commands. [coupled with
> > a "first bad byte" offset.]
> >
> > This is missing today.
> >
> > 2) Also, as discussed above, a general "No Addional Explanation" type of
> > status code in the login response would cover the "misc" category.
> >
> > 3) There are cases of ambiguity in the usage of REJECT or SCSI Response.
> > Take the case of a "SNACK Reject". It is present in both the SCSI
> > Response (SNACK Rejected) and REJECT PDU reason code (Data SNACK
> > Reject). Which mechanism is to be used in this case ?
> >
> > 4) There is no "Status SNACK Rejected" in the REJECT PDU.
> >
> > Regards,
> > Santosh
> >  - santoshr.vcf
> >
> >
> >
> >
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