RE: iSCSI: key negotiation - Unrecognized value?

[pat_thaler@agilent.com]

Santosh,

If it is during Login Phase, then the target can't send a Reject PDU to
indicate protocol error because only Login Request and Login Response PDUs
are allowed. 

A Login Response with a status class of Initiator Error and a status detail
of Initiator Error seems reasonable. None of the other status details seem
to quite fit the description. An invalid value isn't a missing parameter.

That would be consistant with the text on Negotiation Failures. 

I don't think it should respond to the key with not understood, but a
response to the key of Reject would be reasonable and doing so might make it
easier to debug the negotiation problem.

Regards,
Pat

-----Original Message-----
From: Santosh Rao [mailto:santoshr@cup.hp.com]
Sent: Wednesday, February 20, 2002 12:08 PM
To: IPS Reflector
Subject: Re: iSCSI: key negotiation - Unrecognized value?


Hello,

It seems like there are several possible responses on seeing a numeric
key being offered with a non-numeric key value. (ex :
"MaxBurstSize=yes", or "MaxConnections=yes").

1) Target ignores the received key, without affecting basic function. 
It responds to the key with NotUnderstood. 
Login negotiation outcome is then initiator implementation dependent.
Most likely, the initiator will terminate the TCP connection and error
back to the caller indicating that it could not open an iscsi
connection.  

2) Target may respond with a Reject PDU response indicating a "protocol
error". No login response is sent in this case (?). 

3) Target responds with a login response pdu indicating a
status_class_detail of 0x0207 (Missing Parameter).

4) Target may react to this error as a "format error" and close the TCP
connection. 

In all the cases, the end result is TCP connection termination. However,
the response (2) is the least desirable, since no long response is
generated.

I believe that (1) coupled with (3) is the most desirable behaviour. 

Regards,
Santosh



Julian Satran wrote:
> 
> If it is not a list element the it is Reject. If it is a list element
> and you recognize others then ignore the "bad" value else "Reject".
> 
> Regards,
> Julo
> 
>  "KRUEGER,MARJORIE (HP-Roseville,ex1)"
>  <marjorie_krueger@hp.com>                     To:        "Ips
>  Sent by: owner-ips@ece.cmu.edu        Reflector (E-mail)"
>                                        <ips@ece.cmu.edu>
>  20-02-02 03:22                                cc:
>                                                Subject:        iSCSI:
>                                        key negotiation - Unrecognized
>                                        value?
> 
> 
> 
> What is the proper response if you recognize a key, but are offered a
> value
> that you don't recognize?  For instance, what if MaxConnections=yes is
> offered?
> 
> Where is that specified in the document?
> 
> Marjorie Krueger
> Networked Storage Architecture
> Networked Storage Solutions Org.
> Hewlett-Packard
> tel: +1 916 785 2656
> fax: +1 916 785 0391
> email: marjorie_krueger@hp.com

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