G.729 Floating License Explained
This is a robust, peer-to-peer system. All machines on the same subnet co-operate to select a license server. If this machine goes down, the remaining machines renegotiate to select a new license server. All the original licenses will then be available.
Note that if a machine goes down which is not the license server, nothing is affected (apart from a short delay before the licenses in-use on that machine become available again).
Howler floating license rely on UDP broadcast on the subnet to find the other nodes. After this, a low-latency point-to-point UDP-based protocol is used.
Warning
The only caveat is that, once a machine goes down, you have a 2-day window to get it back up, otherwise licenses associated to that machine will become invalid. In most cases this should be fine. If a machine dies, and its network card can be put in another machine, this will unlock the license. If this is not possible we can reassign the license to a new MAC address on a new machine for you.
There is a short window (a few seconds) between the license server going down, and the new license server coming up, during which licenses cannot be shared. During this window, existing calls are unaffected, but new calls may be rejected.
See also:
Asterisk server supports it in pass-thru or with a Asterisk G.729 Licensing