In this section:

Use this window to enable or disable flags that specify local ringback tone behavior within a selected Tone and Announcement Profile.

 

Note

For information on Delayed Local Ring Back Tone (DLRBT) and P-Early-Media, see here.


To View and Edit Flags

On the SBC main screen, navigate to All > Profiles > Media > Tone And Announcement Profile > Local Ring Back Tone > Flags.

Select the desired Tone And Announcement Profile from the drop-down list to view its respective Flags parameters.

The Flags window is displayed.

Note

To view the flag Announcement Based Tones, the option Signaling Tone Package State must be enabled in Local Ring Back Tone.



Flags Parameters

ParameterDescription
Use This Lrbt For Egress

The LRBT state of the Egress leg:

  • Disable (default)

  • Enable
Use This Lrbt For Ingress

The LRBT state of the Ingress leg:

  • Disable (default)

  • Enable
Dynamic LRBT

Use this flag to play tone locally on receipt of 180 with SDP, until RTP is received from the remote peer. 

  • Disable (default)

  • Enable
Force LRBT

Use this flag to play tone locally on receipt of any 18x with or without SDP, until 200 OK (INVITE) or UPDATE is received from the remote peer.

  • Disable (default)

  • Enable
Announcement Based Tones

Use this flag to play tones as announcements by using stored files. This mode does not use DSP resources.

  • Disable (default)
  • Enable

NOTE: If this flag is disabled, the SBC uses DSP (TNAPAD) to generate and play tones.

With or Without SDP

Use this flag to specify whether to play tones when a P-Early-Media (PEM) header is received in the 18x response, with or without SDP.

  • Disable (default)
  • Enable

 To configure this flag, you must configure the Early Media Method flag as P Early Media.

Early Media Method

This flag is used to specify whether playing tones is governed by receipt of a PEM header.

  • P Early Media – The SBC plays tones when it receives a PEM header.
  • None (default) – The SBC is not governed by the PEM header.

Make the required changes and click Save at the right hand bottom of the panel to save the changes made.


P-Early-Media and Delayed RBT

To use the Force Local Ring Back Tone (FLRBT) feature, set the PSX flag DelayedRBTWithToneContinuation to enabled. The flag is available under the entity Tone Generation Criteria > Delayed RBT in the PSX.

  • To create a Tone Generation Criteria entity with the flag DelayedRBTWithToneContinuation:
    create Tone_Generation_Criteria_Data Tone_Generation_Criteria_Id <string> Sequence_Number <int> [Response_Code <short>] [Attributes <int>] [Ingress_Tg <string>]

  • To update a Tone Generation Criteria entity with the flag DelayedRBTWithToneContinuation:
    update Tone_Generation_Criteria_Data Tone_Generation_Criteria_Id <string> Sequence_Number <int> [Response_Code <short>] [Attributes <int>] [Ingress_Tg <string>]

  • To delete a Tone Generation Criteria entity with the flag DelayedRBTWithToneContinuation:
    delete Tone_Generation_Criteria_Data Tone_Generation_Criteria_Id <string> Sequence_Number <int>

For more information on the flag DelayedRBTWithToneContinuation, refer to the PSX document Tone Generation Criteria Screen.


When a caller sends a SIP INVITE to the SBC (irrespective of the presence of "P-Early-Media: supported" header in the Session Description Protocol (SDP) of the INVITE), the SBC adds P-Early-Media header in its 18x (180 or 183) response towards ingress call leg only if:

  • The SBC monitors and detects early media from the egress call leg.

    Note

    The SBC has an "observation" window for monitoring the stream of RTP packets. It also has a "silence" window before it restarts monitoring, to reject RTP packets from a previous announcement.

  • The SBC plays a Ring Back Tone (RBT).

    Note

    The SBC plays LRBT only if it does not receive any early media from the egress call leg at the end of a monitoring cycle. If the SBC starts playing LRBT, it continues to play even if it detects RTP in the subsequent monitoring cycles, or exchanges a new set of SDP answers with the egress call leg.

    When the SBC receives an UPDATE from the egress call leg, and the caller (ingress call leg) does not support UPDATE, the SBC continues to feed tone in the same codec. When the ingress call leg supports UPDATE, the SBC feeds tone in a modified codec after a successful offer-answer negotiation.

Note

If the egress call leg responds with P-Early-Media header in its 18x response, the SBC transparently relays it to the ingress call leg.


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