Re: iSCSI : target session login behaviour

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

"BURBRIDGE,MATTHEW (HP-UnitedKingdom,ex2)" wrote:
> 
> Hari,
> 
> In response to your email
> 
> Either:
> 
> The two HBAs are operating independantly (i.e. sessions do not span HBAs)
> and therefore should have some form of differentiation: e.g. a different
> iSCSI Initiator name, 


One would hope that such mis-abuse of the Initiator Name (WWUI) is not
repeated as was done with the FC Node WWN. The Initiator & Target Names
(WWUI) are explicitly defined in the name-disc draft as :

"The terms "initiator name" and "target name", when used in this
document, refer to iSCSI Node Names."

<snip snip>

"The Initiator Name corresponds to the logical operating system on which
the initiator is running, and the Target Name corresponds to the target
Storage Node entity."

<snip snip>

"An iSCSI Name really names a logical software entity, and is not tied
to a port or other hardware that can be changed.  For instance, an
Initiator Name should name the iSCSI initiator driver, and not a
particular NIC or HBA card.  When multiple NICs are used, they should
generally all present the same iSCSI Initiator Name to the targets,
since they are really to the same entity.  In most operating systems,
the named entity is the operating system image.  Most hosts will have a
single OS running; some of the really big ones could have multiples. 

A target name should similarly not be tied to hardware interfaces that
can be changed.  A Target Name should identify the logical  target,and
must be the same for the target regardless of the physical porton which
it is addressed.  This gives iSCSI initiators an easy way to determine
that two targets it has discovered are really two paths to the same
target." 

The wording above should be strengthened from "should" to "MUST".
Failure to do so could result in the same mis-abuse as has occured with
FC Node WWNs.

Ex : 
"For instance, an Initiator Name MUST name the iSCSI initiator driver,
and not a particular NIC or HBA card."

"When multiple NICs are used, they MUST present the same iSCSI Initiator
Name to the targets, since they are really to the same entity."

- Santosh

> > -----Original Message-----
> > From: Mudaliar, Hari [mailto:Hari_Mudaliar@adaptec.com]
> > Sent: 26 April 2001 00:57
> > To: 'Santosh Rao'; Mudaliar, Hari
> > Cc: IPS Reflector
> > Subject: RE: iSCSI : target session login behaviour
> >
> >
> > Santosh,
> >       I get your point. But what if there is more than one
> > iSCSI Host bus
> > adapter in a system? The Initiator Name will be the same and
> > ISID MAY turn
> > out to be the same (unless the ISIDs are apportioned between
> > the initiators
> > through some configuration method). This assumes that
> > multiple sessions can
> > exist between one initiator system (containing multiple iSCSI off-load
> > engines/HBAs) and a target.
> >
> > - Hari
begin:vcard 
n:Rao;Santosh 
tel;work:408-447-3751
x-mozilla-html:FALSE
org:Hewlett Packard, Cupertino.;SISL
adr:;;19420, Homestead Road, M\S 43LN,	;Cupertino.;CA.;95014.;USA.
version:2.1
email;internet:santoshr@cup.hp.com
title:Software Design Engineer
x-mozilla-cpt:;21088
fn:Santosh Rao
end:vcard