IMPORTANT

The Transparency Profile is the recommended method of configuring transparency on the SBC Core for new deployments as well as when applying additional transparency configurations to existing deployments. Do not use IP Signaling Profile flags in these scenarios because the flags will be retired in upcoming releases.

Refer to the SBC SIP Transparency Implementation Guide for additional information.

This object defines the audio transparency settings for the SBC. The SBC manages bandwidth for audio stream in the pass-through calls. Audio codecs that are unknown to the system are available to setup audio calls or streams.

The SBC Core supports audio transparency in relaying unknown attributes and a subset of known attributes, such as rtpmap, fmtp, and T38 fax. The SBC also manages bandwidth for audio streams in pass-through calls. Audio transparency is controlled by the following PSP and Trunk Group parameters/flags.

Packet Service Profile:

  • Enable transcoderFreeTransparency for the session (enable on either of the PSPs)

  • Configure Audio Transparency settings

  • Enable/disable Reserve BW For Preferred Audio Common Codec

SIP Trunk Group:

See SBC SIP Transparency Implementation Guide for transparency implementation details.

Bandwidth (b) lines are transparently relayed and does not play any role in calculating the unknown audio codec bandwidth. The following PSP configuration bits for Audio Transparency feature are included for Unknown audio bandwidth reservation to calculate the Unknown audio bandwidth:

  • Unknown Codec Packet Size

  • Unknown Codec Bit Rate

If the bandwidth is not configured, the Unknown Codec Packet Size and Unknown Codec Bit Rate are used for the pass-through call.

To View and Edit Audio Transparency

On the SBC main screen, go to All > Profiles > Media > Packet Service Profile > Audio Transparency.

Select the desired Packet Service Profile from the drop-down list to view the respective Audio Transparency parameters.

The Edit Audio Transparency window is displayed.

Edit Audio Transparency

The following fields are displayed:

Audio Transparency Parameters

ParameterLength/RangeDescription
Unknown Codec Packet Size5-100 ms

Specifies the Packet Size (in terms of milliseconds) required for Bandwidth computation of unknown audio codecs. Default value: 10 ms

Unknown Codec Bit Rate1-1000 KB/s

Specifies the Bit Rate (in terms of kbps) required for Bandwidth computation of unknown audio codecs. Default value: 124 KB/s

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