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Liaison statement
LS to IETF AVT WG, ITU-T SG11 and FG CarCom on Requesting Assitance on the Protocols for draft new Recommendation ITU-T G.MDCSPNE

State Posted
Submitted Date 2009-02-18
From Group ITU-T-SG-16
From Contact Simão Ferraz de Campos
To Group avt
To Contacts Roni Even <>
Tom Taylor <>
Cc ITU-T SG11 (
FG CarCom (
Response Contact SG 16 secretariat (
Technical Contact Dominic Ho (
Harald Kullmann (
Purpose For action
Deadline 2009-05-31 Action Taken
Attachments Draft 8 of G.MDCSPNE "Mechanism for Dynamic Coordination of Voice Enhancement SPNE"
ITU-T Q18 of WP1/16 would like to request your assistance to identify if there
are existing protocols (e.g. RTP packet definitions) that can be utilized to
realize the dynamic coordination mechanism defined in the draft new
Recommendation ITU-T G.MDCSPNE over IP networks.

G.MDCSPNE defines a generic framework and protocol requirements for a
coordination mechanism intended to minimize undesirable interaction of voice
processing functions present on bearer paths of a communication link, for the
purpose of improving overall end-to-end voice quality.  Voice quality
improvement is achieved through the usage of “capability lists”, exchanged
among nodes on the bearer path, to identify the state of signal processing
functions (available/unavailable) over a call connection.  This information is
then used to refer to a common “rule book” to cause the de-activation of
redundant functions, and the retention of the signal processing functions that
are in most favourable locations for improving voice quality. One important
aspect of G.MDCSPNE is that it allows dynamic coordination of signal processing
functions/devices during a call.  Dynamic coordination is needed in response to
changes in signal processing function availability due to, for example, call
topology changes such as call transfer or call handover, all within the same
call session. The generic capability list format structure and the rules for
de-activation and retention, based on this state information, have been
finalized in G.MDCSPNE. The scope of G.MDCSPNE, however, does not cover the
definition of protocols for the exchange of capability list information on the
bearer path to realize the coordination mechanism over IP networks.

ITU-T Q18 of WP1/16 would like to request your assistance in identifying if
there is (are) existing standard specifications that could serve as a vehicle
for exchange of state of availability of voice processing functions among nodes
on a call-path, to satisfy the requirements for a dynamic coordination
mechanism over IP networks as contained in ITU-T Q18/16 draft G.MDCSPNE.

ITU-T Q18/16 understands that modification of the generic capability list
format structure in G.MDCSPNE may be needed in order to take advantage of
existing specifications to implement the dynamic coordination mechanism.  If
such should be the case, ITU-T Q18/16 would appreciate very much if you would
provide the modifications needed.

For information purposes, attached please find the latest version of G.MDCSPNE
for your reference.  G.MDCSPNE is expected to go for consent at the ITU-T
October 2009 SG16 meeting and become an ITU-T standard afterwards.

-       Draft 8 of G.MDCSPNE “Mechanism for Dynamic Coordination of Voice
Enhancement SPNE”