The announcement will only play from a board where the file exists.

Free tip: If you upload WAV files to different boards in an Audio Group, remember to update them all. If one old copy of a file exists on one board, a random caller will hear that and not the updated file!

And is it necessary to upload a file on all the board in the Audio group.???

And what happens when the audio ports exhaust ??

Will call send a request to the board where file doesn't exists ??

You do not need to upload the file to every board, But not utilizing every board in a group implies you could have a smaller group.

Announcement boards have a maximum number of ports for playing announcements, depending on the media-gateway or board. Once the board hits that maximum then callers hear silence. There are a couple of other factors such as setting the announcement for queue or barge-in but in general callers start hearing silence.

The Audio group allows you to increase that maximum with additional boards and thus more ports. In your example, your audio group gives you up to 6 times as many ports. If you only use 4 boards then you will only have 4 times as many ports. That may be fine for your call volume. You can check for any announcements that get blocked with the list measurements command.

The call does not "send a request". Rather, the system looks at where the call came in and uses the Board that is closest network-wise. If the call is on a PRI in that gateway then that gateway announcement board will be used first.

I hope that helps.

Thanks a lot sir ... very informative