Maintenance Manual

guaranteed to be available. If, for instance, the MCU has 20 video ports available in total, it will not be possible to set
up two conferences which require 15 video ports each if they are scheduled such that they ever overlap.
In the simple case of conferences which start at specific times and end at specific times (or, indeed, are permanent),
it is easy to see whether they clash. The more complex cases involve repetition, and it is important to bear in mind
that port reservations are only permitted when the MCU can guarantee them for every repetition of a conference. As
an example, a conference scheduled to run from 08:00 to 10:00 on the second Monday of each month will be deemed
to clash with a conference configured to run from 09:00 to 09:30 every Monday, even though the former will only
really clash with the latter every fourth or fifth week.
In general, to make best use of the available MCU media ports, you should not schedule conferences to be longer
than needed, and you should limit repetitions, either by end date or number, wherever possible.
Ad Hoc Conferencing
Because port reservations are mandatory in Reserved mode every active conference must have configured values
for the number of video ports and the number of audio-only ports to reserve for it. In turn this means that every active
conference must be configured, and therefore ad hoc conferences are not permitted when in Reserved mode.
This affects the operation of the MCU in the following ways:
■ Auto attendant usage
In reserved mode, the Create new conference option will not be shown on video auto attendant menus, even
for auto attendants configured to display this option.
■ Auto attendant configuration
When configuring new or existing auto attendants via the web interface, the Creation of new conferences
parameter will not be available.
■ Calls to unknown E.164 number configuration
This setting on the Conference settings page also offers a Create new conference option. This is not available
in reserved mode and becomes equivalent to the Disconnect caller option.
Auto attendant connections
If a participant calls in to the MCU and connects to an auto attendant, the MCU does not know which conference they
will join until they make a selection from the auto attendant menu.
In Unreserved mode, the auto attendant connection allocates a media port from those not currently in use. If all of the
media ports are in use, the endpoint's connection will be dropped by the MCU.
In Reserved mode, the auto attendant connection effectively "borrows" a media port from those not currently in use.
However, this borrowed media port has a lower priority than a media port used by a conference participant, and if the
auto attendant connection "borrows" the last remaining media port, then that connection will be dropped if another
endpoint connects directly to a conference and requires a reserved media port.
Changing MCU Port Reservation Mode
In general, changing port reservation mode when there are active connections is not recommended. The effects of
changing mode include, but are not necessarily limited to:
■ Destruction of ad hoc conferences
Any ad hoc conferences in progress will be destroyed when changing to port reservation mode and their
participants dropped because ad hoc conferences are not permitted in port reservation mode.
■ Participant disconnection
Participants in a scheduled conference may be disconnected. For each conference, the maximum port usage
values (for unreserved mode) and the ports to reserve (for reserved mode) are configured and stored
separately. Therefore when changing port reservation mode, it is possible that there are more active
participants than allowed in the particular mode. In this case, participants are disconnected to reduce the
number to that allowed.
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