MWI - Message Waiting Indication

Markku Korpi korpim at SCN.DE
Mon Mar 20 15:30:01 EST 2000

H.450.7 MWI was made made for the purpose you indicate.
The MWI uses non-call associated signalling connection, i.e. a connectioon
that looks like a normal H.323 call, does not have any logical channel and
is (usually) immediately released.

The messaging server actually sends the MWI to an H.323 address and does
not need to know how MWI is processed at the terminating side. A gatekeeper
(or a separate feature server) may, of course, act on behalf of the
terminal and intercept the MWI for specific terminals. And as indicated by
Bob Gilman in his answer, the GK/Feature server can then use, for example,
Annex L stimulus signalling to control the terminals display and MWI lamp
or other indicator.

On the other hand, if I have an intelligent H.323/H.450 terminal, that
processes the MWI, I probably want my gatekeeper to pass the MWI
transparently to my terminal.

Additionally you can open an Annex K HTTP session within the MWI procedure
- provided the terminal (or its feature server) supports Annek K.

One more point: H.450.7 follows (not by accident...) QSIG MWI procedures,
so that seemless interworking with PBX networks is relatively easy to
implement in the gateways.

Perhaps somebody else on the list can comment the status of ongoing SIP
work with regard to MWI. I would just say that, in order to reach "world
wide feature control", it would be very important to follow the same
functional procedures and functional message content, regardless of the
underlying protocol. This is already demonstrated by using same functional
procedures in H.323 and in QSIG, and this principle should/could be also
applied IMO to SIP.

Markku Korpi

-----Original Message-----
From: Michaely, Boaz [mailto:Boaz_Michaely at ICOMVERSE.COM]
Sent: Sonntag, 19. Marz 2000 12:13
To: ITU-SG16 at
Subject: MWI - Message Waiting Indication

Hi folks,
Please forgive my ignorance in case this is already a done deal, but does
anybody know where we are standing in regard to MWI ?

Two aspects seem to be of interest:
1. (to the GK ) -
A method for a Voice Messaging System to signal the GK that a certain
subscriber has a new message.

2. (to the terminal) -
A method for the GK or the VMS itself to signal the terminal that the
subscriber associated with it has a new message

Do we have any means in general for signalling call-unrelated information
(other than RAS) , that should be used for this purpose? e.g. is Annex K
(HTTP) a suitable candidate ?
Is H.450 suitable for call unrelated information ?
Is anyone aware of similar work done e.g. in SIP which we may reuse or
consider to avoid interworking problems ahead of time ?

Best regards,
-- Boaz

Boaz Michaely
Senior System Architect, Corporate
Comverse Network Systems
Tel: +972 (3) 766-3844 , Mobile +972 (50) 39-30-17
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