Re: SUA Address Indicator

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.
>