Voicemail msg waiting indications

Hi all,

I have an application that has support to both H.323 and SIP. If i configure my endpoint to have voicemail mailbox in Asterisk, what is the way by which i can get a visual message waiting indication at the endpoint ?

What is the protocol or mechanism by which the message waiting indication is given to the endpoint ? Does Asterisk support H.450.7 for H.323 endpoints ?

Kindly provide your valuable feedback . Awaiting a positive response at the earliest.

Thanks in advance,