Information Technology Reference
In-Depth Information
If participants cannot be added to an ad-hoc conference, this might be because of a number of issues,
including
that the phone in
question is not associated with an MRGL, that the IP Voice Media Streaming Application service has not been started, or that the
conference bridge is out of resources.
MeetMe conferences, in contrast, require a specific conference directory number (range) to be configured on CUCM in advance. The
conference controller establishes the MeetMe conference by pressing the MeetMe button or softkey. Other participants in the MeetMe
conference dial the number specified by the conference controller to join the conference.
Note that some Cisco IP phone models also have a built-in digital signal processor (DSP) and conference capability that allows
conferencing with a maximum of three participants. This conferencing capability is enabled using the Barge softkey.
Hardware conference bridges enable conferencing by mixing participants' audio streams using DSPs. They support a range of codecs,
including G.711, G.729, and G.723. Hardware conference bridges that support multiple low-bit-rate codecs, such as G.729 or G.723,
transcode between these codecs in a mixed-mode conference call.
Software conferences depend on CUCM's Cisco IP Voice Media Streaming Application to mix participants' audio streams, and they
can support a smaller range of codecs, including G.711 and wideband codecs. If devices using other codecs want to participate in a
conference call, a hardware transcoder is required to allow their participation.
The Cisco IP Voice Media Streaming Application on a standalone server supports up to 64 participants for ad-hoc conferences and up
to 128 participants for a MeetMe conference.
Hardware conferences resources can include the following:
■
NM-HDV
■
NM-HDV2
■
NM-HD-1V/2V/2VE
■
PVDM/PVDM2/PVDM3
■
WS-SVC-CMM-ACT
