Re: iSCSI: Connection termination conditions

["Nandakumar Ramamurthy" <nramamur@npd.hcltech.com>]

Hi Mallikarjun,

Agreed that there exists a distinction between a TCP connection
and an iSCSI connection.  IMHO, an iSCSI logout should precede sending
TCP FINs.  Section 2.2.6 must offer a clearer explanation in this regard.

As the section is entitled "iSCSI Connection Termination", there should be
more
focus on termination of an iSCSI connection. A separate section
entitled "TCP Connection Termination" could probably speak about TCP related
intricacies.

My understanding of iSCSI connection termination is :

An intentional and graceful iSCSI connection termination MUST occur
only through the iSCSI logout process ( either implicit or explicit ).
This is not clear from section 2.2.6.
( Are the 2 situations specified in my earlier mail valid? )

Section 3.13.5 states :
"If the Status Class is not 0, the initiator and target MUST close the TCP
connection."
Does this constitute a graceful TCP connection termination?

What are the other interpretations for a "graceful" iSCSI connection
termination?

Can "graceful" connection termination happen when it is not in full-feature
phase?  How?
Please describe the related mechanism.

Thanks,
Nandakumar
Member Technical Staff
HCL Technologies, Chennai, INDIA.
http://san.hcltech.com


----- Original Message -----
From: "Mallikarjun C." <cbm@rose.hp.com>
To: <ips@ece.cmu.edu>
Sent: Monday, January 14, 2002 11:44 PM
Subject: Re: iSCSI: Connection termination conditions


> Nandakumar,
>
> As the preceding sentence indicates, the "graceful connection
> shutdown" being referred to is the TCP connection termination.
>
> All the text is saying is that the an intentional and graceful
> transport connection termination must also be "graceful" wrt iSCSI.
> The first sentence in this section requires rewording for rev10,
> and I suggest ignoring it for now.
>
> Thanks.
> --
> Mallikarjun
>
>
> Mallikarjun Chadalapaka
> Networked Storage Architecture
> Network Storage Solutions Organization
> MS 5668 Hewlett-Packard, Roseville.
> cbm@rose.hp.com
>
>
> Nandakumar Ramamurthy wrote:
> >
> > Hi All,
> >
> > Section 2.2.6 specifies two conditions for connection termination :
> >
> > "Graceful connection shutdowns MUST only occur when there are no
> >  outstanding tasks that have allegiance to the connection and when the
> > connection is not in full-feature phase."
> >
> > The above statement is ambiguous as to what a graceful connection
> > shutdown is and the conditions in which this may occur. Can "graceful
> > connection shutdown" be elaborated upon?
> >
> > My interpretation is that there could be 2 possible cases when graceful
> > connection termination may occur. They are as follows:
> >
> > 1) A connection logout with no outstanding allegiant tasks is the first
> > condition.
> > In this case, the state of the connection is full feature.
> >
> > 2) The second case is when the connection is shutdown and the connection
> > state is not in full feature phase i.e., in SecurityNegotiation or
> > LoginOperationalNegotiation
> > phase.
> >
> > Is that the correct interpretation?
> >
> > Thanks,
> > Nandakumar
> > Member Technical Staff
> > HCL Technologies, Chennai, INDIA.
> > http://san.hcltech.com
>