Howto12r1:Conferences, Resources and Licenses

Applies To

This information applies to

all innovaphone devices supporting a CONF interface and hence Conferencing Channels (as shown in the devices home-page).

More Information

Performing conferencing on a CONF interface consumes both resources and licenses. Here is an overview of which and how much.

Overview

First let us have a look at the overall scheme:

The CONF interface provides for the mixing of audio channels. As it features a PCM interface for each available Conference channel, it can interface directly to TDM interfaces such as ISDN (if Enable PCM is enabled). However, when the audio channel originates from a VoIP endpoint, a Coder channel from the DSP channel bank is required to interface to the conferencing circuitry.

As a result, a caller from e.g. the ISDN needs an available B-channel on the ISDN interface. There are no licenses for B-channels required, but the ISDN interface itself must be licensed. In addition, a Conference Channel is required. There is no license required to use a Conference Channel, however, such channels are a limited resource (depending on the platform), so there must be one available.

A caller from a VoIP endpoint establishes a connection through the conferencing unit's VoIP interface. There are no license for such connections required, but the VoIP interface itself needs to register with the PBX and thus a Port license is required. Also, to connect the audio stream to the conferencing circuitry, one DSP channel is required per such call. As there are licenses required for use of a DSP channel, both the DSP (Channel) license and the DSP channel itself must be available (depending on the platform).

caller	conference channel	Channel License (Relay-Channels)
PSTN	1	-
VoIP	1	1

Let us assume we have a conference with one PSTN and 3 VoIP participants. In this case, we have

caller	conference channel	Channel License (Relay-Channels)
1 PSTN	1	-
3 VoIP	3	3
Total	4	3

Looking at an IP305, it supports the following resources:

Coder      4 Channels of G.711,G.729,G.723
Conference 4 Channels

We can see that our sample scenario will work on an IP305 (if the ISDN interface is licensed and 4 Channel licenses are available). However, keep in mind that DSP channels and licenses are used for straight gateway calls too. In our sample scenario, although we have 2 BRI with 4 B-channels, we cannot use 4 B channels, as we run out of DSP channels (as each call from an ISDN interface to a VoIP endpoint uses one DSP channel too).

The resources (and hence the licenses) are required on the device that provides the CONF interface. If you do not want to cannibalize your PSTN gateway ressources and run the risk of not being able to perform PSTN calls due to missing DSP channels consumed by conferencing calls, you can easily add an extra gateway with CONF support just for conferencing (the IP0010 or IP1060 may be a good choice, featuring 60 conferencing channels).

IPVA

There are some platforms which do not support conferencing channels at all. Most prominent, this is the IPVA. To use conferencing, you must supply an external conferencing-capable platform (such as the IP0010/IP1060).

3PTY Conferencing

3-way conferencing is special as it is usually implemented internally in the innovaphone IP phones. That is, each user of an innovaphone IP phone (except the IP61) has internal conferencing ressources built-in to allow for a 3-way conference. No external CONF interface is needed.

However, on innovaphone DECT phones, no internal conferencing resource is present and hence no internal 3PTY is possible. The DECT system can thus be configured to use an external conferencing resource for 3PTY. In this case, the rules above apply.

Note: if you configure ITALY-PUBLIC dial tone on the phones, you will hear every 5 seconds a "bip" during the 3PTY conference. This has been added to be in line with the italian law regarding conference.

Multi-party Conferencing from myPBX V9

V9 myPBX has a built-in interface to multi-party conferencing. Although myPBX hides all the details of allocating the conference resources from the user, it still uses the same mechanism. The rules outlined above apply thus.This mechanism is not available in later versions of myPBX.

Related Articles

• Reference9:Concept myPBX
• Reference10:Concept Innovaphone Virtual Appliance
• Reference9:3pty conference on DECT phones
• Reference10:Gateway/Interfaces#Conferencing_interface_.28CONF.29
• Howto:How_to_implement_large_PBXs#Technical_data_and_recommended_number_of_users_supported, lists DSP and CONF resources for the different gateway platforms