Subject: Re: [SUA issues 3,6,7] text

From: "Brian F. G. Bidulock" <[email-masked]>
Date: Tue, 4 Sep 2001 01:00:00 -0500

John,

On Tue, 04 Sep 2001, John Loughney wrote:

[snip]
> > > Optional in CODT
> > 
> > Why is this optional in CODT?  Connections cannot change protocol
> > classes mid connection...  Also, it has been clearly laid out that
> > protocol class can be derived from the presence or absence of the
> > sequence parameter in CODT messages.
> > 
> > Strike the Optional.
> 
> Does that mean you want it MANDATORY or remove support for it in CODT?

CODT implies protocol class regardless.  As DT1, DT2 and ED can be
ascertained from the CODT message, there is no need for protocol
class as an optional parameter in CODT.  This is a recent development
from the clarification of CODT for DT1, DT2, and ED use.

>  
> > ==============================================================
> > ==========
> > > 
> > > 3.10.e Sequence Control
> > > 
> > >    0                   1                   2                   3
> > >    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
> > >   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
> > >   |         Tag = 0x010e         |             Length = 8         |
> > >   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
> > >   |                                               | Seq  
> > Control  |  
> > >   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
> > > 
> > > Sequence Control (1.1.2/Q.714)
> > > 
> > > The field is coded with the value of the sequence control parameter
> > > associated with a group of messages and are chosen so as to 
> > > ensure  proper loadsharing of message groups over SLS values while 
> > > ensuring that sequence control values within message groups have the 
> > > sequence control value coded with the same value as the initial message 
> > > of the message group.
> > > 
> > > 
> > > Mandatory in CLDT, CORE, COAK, COIT.
> > 
> > For decoupled operation, sequence control needs to be
> > 
> >   Optional in all other CL and CO messages.
> 
> So, it should be optional in CLDA, COREF, RELRE, RELCO, RESCO, RESRE,
> COAT, CODA, COERR?  That seems a bit much ...
> 
> Should a be added stating that 'This parameter is needed for decoupled 
> operation.'
> 
> It would be helpful if you would provide a good definition for 'Decoupled
> Operation.'

Decoupled operation (connection-oriented relay without coupling) is defined
in the SCCP specifications.

> 
> > To support non-final GTT, sequence control must be provided in a all
> > CL and CO messages which do not terminate at the peer.

We can address when sequence control is included for decoupled operation as
part of Issue 14 if you'd like.

--brian

-- 
Brian F. G. Bidulock
[email-masked]
http://www.openss7.org/

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