Re: SUA Address Indicator

Chris,

This use of bit 8 has not been in use in the NA network since about 1988.

I know of no vendor equipment, even IGW switches, that support that use.
No local, tandem or domestic toll switch in the NA network has supported
it since.

As the use of bit 8 is long deprecated, it must coded zero regardless of
whether it maps to the ancient application or not (see SS7 interoperability
rules).  So I think the matter is moot and no change is needed to SUA.

--brian

On Wed, 17 May 2006, Chris Benson wrote:

> Hi Warren,
> 
> It is my understanding that bit 8 of the SS7 SCCP Address Indicator is 
> used to distinguish between a National and the International encodings of 
> the SS7 SCCP Address (including the rest of the Address Indicator bits) 
> and applies to the SS7 encoding only.
> 
> For example, SSN and PC indicator positions are swapped between Telcordia 
> T1.112.3 Section 3.4.1 and ITU-T Q.713 Section 3.4.1 specifications. This 
> is indicated by bit 8 being 1 or 0 respectively.  SUA has no such 
> difference of encoding. Bit 8 of the SUA Address Indicator is spare 
> because there is only one SUA Address and Address Indicator format 
> specification (i.e. RFC 3868).
> 
> This is easy for SCCP --> SUA. I think that the SUA --> SCCP direction 
> requires a priori knowledge of SCCP's National or International scope and  
> thus SS7 encoding format.
> 
> This is only my understanding, and I would sure like to
> know if it is incorrect.
> 
> With thanks, from Chris Benson.
> 
> On Wed, 17 May 2006, Warren Anthony Briggs wrote:
> 
> > Hi All,
> > 
> > Could you please clarify the following:
> > 
> > Q.713. section 3.4.1   states that bit 8 of the SCCP Address Indicator 
> > parameter is reserved for national use.   RFC 3868 appears to indicate 
> > that this bit is spare and always 0.  Am I interpreting this correctly 
> > or should this bit have a 1 to 1 mapping  when encoding from SUA to SCCP 
> > and vice versa?
> > 
> > thank you,
> > warren briggs.
> > 
> 
> 
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