We have been installing Asterisk based systems for a few years and this issue has come up alot lately. The issue is that sometimes a message to a phone to turn on a voicemail BLF never makes it to the phone for one reason or another. I am assuming that the system only sends the message once for each new message left. If this is true is there a way to run a cron job or something to “refresh” the message lights ?
There is nothing in ietf.org/rfc/rfc3265.txt that allows for redundant retransmissions, and, in fact, there is a SHOULD level requirement that it should cease sending NOTIFY’s if there is a timeout on the response. It is up to the phone to refresh its subscription.