AW: Rules for sending H.450.1 APDUs

Horvath Ernst ernst.horvath at SIEMENS.AT
Thu Sep 6 05:41:47 EDT 2001


H.450.1 is the framework for individual supplementary service
specifications. Which messages will be used for supplementary service APDUs
is specified in these individual specifications, subject to the rules of
H.450.1. In particular:

- In the context of H.450, a Facility message needs a valid, agreed-upon
call reference.

- Therefore the sender of Setup shall not send a Facility message before
having received a positive response message (e.g. Call Proceeding, but
obviously not Release Complete since the call reference would be no longer

- The recipient of Setup shall not use Facility as first response message -
note that supplementary service APDUs can be included in almost all other
possible response messages.

The last bullet applies only to H.450 standards. It does not mean that
Facility could not be the first response message for other purposes!

Ernst Horvath
Siemens AG

> -----Ursprüngliche Nachricht-----
> Von: Frank Derks [mailto:frank.derks at PHILIPS.COM]
> Gesendet am: Dienstag, 04. September 2001 14:28
> An: ITU-SG16 at mailbag.cps.INTEL.COM
> Betreff: Rules for sending H.450.1 APDUs
> 6.3/H.450.1 states (the third bullet item):
> "a FACILITY message shall not be sent if a SETUP message previously
> sent or received has not been answered"
> It is not clear what constitutes an answer to a SETUP message. Does
> this refer to any response that is the effect effect of sending or
> receiving a SETUP message? E.g. a SETUP ACKNOWLEDGE or a CALL
> PROCEEDING as "response" to having received a SETUP?
> Regards,
> Frank
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> For help on this mail list, send "HELP ITU-SG16" in a message to
> listserv at

For help on this mail list, send "HELP ITU-SG16" in a message to
listserv at

More information about the sg16-avd mailing list