What it does

MMTel Communication Hold (HOLD) is a service that lets a user suspend reception of the media stream(s) of an established IP multimedia session, and resume the media stream(s) at a later time.

This service provides a way for the operator to:

  • restrict bandwidth for held calls

  • play announcements to the held party

  • determine how media streams for the holding party are handled while an announcement to the held party is in progress.

Bandwidth controls

Bandwidth controls allow the Rhino VoLTE TAS to restrict the bandwidth available to media streams to the holding party for the duration of the hold. The call hold service allows you to set three different bandwidth parameters. The values for all of these parameters are set in kilobits per second.

Table 1. Bandwidth parameters
Parameter Config field Description

AS

b-as-parameter

Sets the bandwidth available for application specific data. It is safe to set this to 0.

RS

b-rs-parameter

Sets the bandwidth available for RTCP (Real-time Transport Control Protocol) for participants that are sending data. This should be set high enough to allow RTCP messages to continue while the call is on hold.

RR

b-rr-parameter

Sets the bandwidth available for RTCP for participants that are not sending data. This should be set high enough to allow RTCP messages to continue while the call is on hold.

Announcements

The call hold service can play an announcement to the party that has been put on hold. Call hold configuration only needs the announcement ID of the announcement that should be played. For instructions on how to configure the details of the announcement, see announcements.

Media handling during announcement

While an announcement to the held party is in progress, there are three options on how to deal with the media streams to the holding party. The behavior is configured in the holding-party-media-mode field with the following options.

Table 2. Holding party media modes
Field value Behavior 
NO_HOLD

No change is made to the media streams to the holding party.

 
BLACK_HOLE_ONLY

The media streams to the holding party are directed to a black hole IP address (0.0.0.0 for IPv4 and :: for IPv6) for the duration of the announcement.

 
FULL_HOLD

The media streams to the holding party are put on a two-way hold for the duration of the announcement.

Interactions with other services

Conference (CONF)

If a participant of a conference invokes the HOLD service, it is not desirable to provide an announcement to the conference.

Configuration

The example for sentinel-volte-gsm-config.yaml and example for sentinel-volte-cdma-config.yaml show example configuration relevant to call hold in the sentinel-volte/mmtel/communication-hold section.

What you need

  • ❏ The ID of the announcement to play when the session is held.

Setting up call hold

I want to…​

Set the bandwidth for held media streams

In the communication-hold section, change the values, in kilobits per second, of the bandwidth-adjustment parameters.

           bandwidth-adjustment:
                b-as-parameter: 0
                b-rr-parameter: 500
                b-rs-parameter: 500

Related section: Bandwidth controls

Play an announcement to the held party that the call is on hold
        communication-hold:

            announcement:
                announcement-id: 25

Related section: Announcements

Leave media streams to the holding party unchanged while an announcement is in progress

In the communication-hold section, set the holding-party-media-mode to NO_HOLD.

            holding-party-media-mode: NO_HOLD

Related section: Media handling during announcement

Direct media streams to the holding party to a black hole IP address while an announcement is in progress

In the communication-hold section, set the holding-party-media-mode to BLACK_HOLE_ONLY.

            holding-party-media-mode: BLACK_HOLE_ONLY

Related section: Media handling during announcement

Put media streams to the holding party on a two-way hold while an announcement is in progress

In the communication-hold section, set the holding-party-media-mode to FULL_HOLD.

            holding-party-media-mode: FULL_HOLD

Related section: Media handling during announcement

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Rhino VoLTE TAS Version 4.2