Operating Parameters - Nortel Meridian Meridian 1 Feature Description And Administration

Operating parameters

There are two forms of QSIG Call Transfer - QSIG Call Transfer by the
"rerouting" method, and QSIG Call Transfer by the "join" method. QSIG
Alternate Routing and the QSIG Call Transfer by the "re-routing" method are
mutually exclusive.
Optional Information Elements (IEs) may be lost at a rerouting node. Only the
following optional Information Element (IEs) are tandemmed in the SETUP
of the alternate call, if they are present in the congested call:
• Calling number
• Called and calling subaddress
• High layer compatibility
• Low layer compatibility
On a QSIG network, optional IEs (like progress IEs) carried in the SETUP
messages are lost when the alternate routing occurs at a transit node.
Mandatory IE are always tandemmed transparently.
GF facility information is lost at a transit node. If QSIG Alternate Routing is
performed, Facility IEs contained in the SETUP message are lost, so services
like QSIG Name Display, QSIG Call Diversion (rerouting and by join
method) are not delivered to the end-user. QSIG Alternate Routing is
exclusive with QSIG Call Transfer, if the rerouting method is used. This does
not have a major impact, since QSIG Call Transfer by rerouting is optional,
whereas QSIG Call Transfer by join is mandatory. It is therefore advised that
if a third-party PBX is part of a QSIG network, QSIG Call Transfer by join
method is used.
Missing progress IEs due to QSIG Alternate Routing activation may create a
situation where a call fails involving an ISDN BRI set. This may occur when
a Meridian proprietary set calls an ISDN BRI set over a QSIG link, and QSIG
Alternate Routing is triggered. In this case the Progress Indicator Number 3
"Originator is not ISDN" is lost.
Route Access codes are not supported. A Coordinated Dialing Plan (CDP) or
a Uniform Dialing Plan (UDP) is required for the QSIG Alternate Routing
feature.
International ISDN PRI Feature description and administration
ISDN QSIG Alternate Routing Page 929 of 1814