[Css-csts] protocol question

Tue Dec 6 14:30:29 EST 2005

Hi Ray,

I cannot give you an definitive answer but this is how I understand the SLE
Books.

>From the specification of the PEER-ABORT operation is seems to be quite
clear to me that this operation can be invoked at any time by any party
after a BIND invocation und up to the point where UNBIND return is issued
(provider) or received (user) or a protocol abort occurs.

My understanding of the intention of note 3 in section 4.1.3 is that the
user should no try start or request any activity (e.g. invoke START, request
a status report, or get a parameter) once he has initiated unbinding. In
addition, the note points out that the return for an operation that was
invoked before the UNBIND might not be received by the user because the
provider is not obliged to send that return once the UNBIND invocation
arrived. In such cases, the user should not invoke PEER-ABORT because of the
missing return. 

I do not believe this refers to the case where the UNBIND return is not sent
in good time. If the UNBIND return is missing the association must be
terminated somehow and the means foreseen for such error cases is
PEER-ABORT. 
I believe that my view is supported by clauses 3.3.1.3 including Note and
3.3.1.4 (CLTU Book e.g.)

To be very precise, the note might have been better phrased something  like
the following:

"After invoking the CLTU-UNBIND operation, the initiator must not invoke any
further operations with the exception of the case addressed in 3.3.1.4, nor
send any returns...."

Kind Regards,
Martin Götzelmann

VEGA Informations-Technologien GmbH
Robert-Bosch-Straße 7
D-64293 Darmstadt
Germany

Tel     : +49 6151 8257-147
Fax     : +49 6151 8257-171
Email   : Martin.Goetzelmann at vega.de
Web     : www.vega-group.de

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From: css-csts-bounces at mailman.ccsds.org
[mailto:css-csts-bounces at mailman.ccsds.org] On Behalf Of Tim Ray
Sent: 05 December 2005 20:13
To: css-csts at mailman.ccsds.org
Subject: [Css-csts] protocol question

Hello all,

I can’t complete the User side Operation Layer state tables (due 12/15/05)
until someone answers the question below

The basic SLE protocol (as presented in chapter 4 of the existing SLE data
transfer Blue Books) does not seem to clearly define the User’s response to
certain events that may occur while an Unbind-Invocation is pending (I’ve
capitalized certain words to make the problem clearer):

Section 4.1.1 says to INVOKE THE PEER-ABORT OPERATION in response to an
Unexpected SLE Protocol Data Unit.

Section 4.1.2 says to INVOKE THE PEER-ABORT OPERATION in response to things
like an incoming return that is not decodable.

Section 4.1.3 says to INVOKE THE PEER-ABORT OPERATION in response to a
missing return.

Yet, note 3 within section 4.1.3 says that “After invoking the UNBIND
operation, the initiator MUST NOT INVOKE ANY FURTHER OPERATIONS nor send any
returns”.

May the User invoke a Peer-Abort operation while an Unbind-Invocation is
pending? 

Best regards,

Tim Ray

NASA/Goddard

Tim.ray at nasa.gov

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Hi Ray,
I cannot give you an definitive answer but this is how I understand the SLE Books.
>From the specification of the PEER-ABORT operation is seems to be quite clear to me that this operation can be invoked at any time by any party after a BIND invocation und up to the point where UNBIND return is issued (provider) or received (user) or a protocol abort occurs.
My understanding of the intention of note 3 in section 4.1.3 is that the user should no try start or request any activity (e.g. invoke START, request a status report, or get a parameter) once he has initiated unbinding. In addition, the note points out that the return for an operation that was invoked before the UNBIND might not be received by the user because the provider is not obliged to send that return once the UNBIND invocation arrived. In such cases, the user should not invoke PEER-ABORT because of the missing return.
I do not believe this refers to the case where the UNBIND return is not sent in good time. If the UNBIND return is missing the association must be terminated somehow and the means foreseen for such error cases is PEER-ABORT.
I believe that my view is supported by clauses 3.3.1.3 including Note and 3.3.1.4 (CLTU Book e.g.)
To be very precise, the note might have been better phrased something like the following:
"After invoking the CLTU-UNBIND operation, the initiator must not invoke any further operations with the exception of the case addressed in 3.3.1.4, nor send any returns...."
K
ind Regards,
M
artin Götzelmann
VEGA Informations-Technologien GmbH
Robert-Bosch-Straße 7
D-64293 Darmstadt
Germany
Tel : +49 6151 8257-147
Fax : +49 6151 8257-171
Email : Martin.Goetzelmann at vega.de
Web : www.vega-group.de
Notice of Confidentiality
This transmission is intended for the named addressee only. It contains information which may be confidential and which may also be privileged. Unless you are the named addressee (or authorised to receive it for the addressee) you may not copy or use it, or disclose it to anyone else. If you have received this transmission in error please notify the sender immediately.
From:
css-csts-bounces at mailman.ccsds.org [mailto:css-csts-bounces at mailman.ccsds.org]
On Behalf Of
Tim Ray
Sent:
05 December 2005 20:13
To:
css-csts at mailman.ccsds.org
Subject:
[Css-csts] protocol question
Hello all,
I can’t complete the User side Operation Layer state tables (due 12/15/05) until someone answers the question below
The basic SLE protocol (as presented in chapter 4 of the existing SLE data transfer Blue Books) does not seem to clearly define the User’s response to certain events that may occur while an Unbind-Invocation is pending (I’ve capitalized certain words to make the problem clearer):
Section 4.1.1 says to INVOKE THE PEER-ABORT OPERATION in response to an Unexpected SLE Protocol Data Unit.
Section 4.1.2 says to INVOKE THE PEER-ABORT OPERATION in response to things like an incoming return that is not decodable.
Section 4.1.3 says to INVOKE THE PEER-ABORT OPERATION in response to a missing return.
Yet, note 3 within section 4.1.3 says that “After invoking the UNBIND operation, the initiator MUST NOT INVOKE ANY FURTHER OPERATIONS nor send any returns”.
May the User invoke a Peer-Abort operation while an Unbind-Invocation is pending?
Best regards,
Tim Ray
NASA/Goddard
mailto:Tim.ray at nasa.gov Tim.ray at nasa.gov