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To create or modify a Media List:

  1. In the WebUI, click the Settings tab.
  2. In the left navigation pane, go to Media > Media Lists.

Modifying a Media List

  1. Click the expand () Icon next to the entry you wish to modify.
  2. Edit the entry properties as required, see details below.

Creating a Media List

  1. Click the Create Media List ( ) icon at the top of the Media List View page.

Media List - Field Definitions


Name/description for the Media List.

Media Profiles List

Specifies a list of Media Profiles to be used in this Media List.

The order of the codec profile controls the order in which the codecs will be listed in the SIP message(s) sent to the peer. They should be listed in the order of user preference; the more desirable codecs listed first (above). The following are options to move/add/edit  the profile:

  • Up. Moves the profile up in the list.
  • Down. Moves the profile down in the list.
  • Add/Edit. From the Select Media Profile box, click to select a profile and click OK. The profile is added to the list.
  • Remove. Removes the profile from the list.


Helpful Hint

This field presents a multi-select widget when the Add/Edit button is clicked.
Click here for more information about using the Multi-select widget.

When selecting the G729 profile:  If your device supports only G729a, then be sure to configure Silence Suppression to Disable.  The G729a codec does not support Silence Suppression.

Crypto Profile ID

Specifies the Media Crypto Profiles to be used with this Media List.

If you are not using (Secure Real Time Protocol (SRTP), set this parameter to None.

Media DSCP

Each Media List is configurable with the DSCP value to be used for media flow. All media flows that are created using this media list share the same DSCP value. Typically, a SIP Signaling Group selects the media list to be used for the calls using that Signaling Group. The default value is 46 and the allowed range is [0..63]. The configured value should be chosen according to the QoS policies of the IP network traversed by the media packets.


Specifies either RTCP or RTCP-XR usage for this profile

RTCP: The Sonus SBC 1000/2000 sends basic RTCP messages to the peer.

RTCP-XR(Extended Reports): The RTCP-XR packets have more information, however, some SIP endpoints may not be handle the \-XR packets, in which case basic RTCP should be specified.

RTCP-XR (Real Time Control Protocol - Extended Reports) provides packet transport quality metrics. The metrics are designed to supplement the packet-loss metric in RTCP and the roundtrip delay measurement provided by RTCP. They provide metrics for IP Packet Delay Variation based on the IPDV metric defined in, metrics reporting the activity of the RTP end system's receiver's jitter buffer, and metrics reporting "errored" and "severely errored" seconds.

For more information about this topic, see RFC 5093.

If the RTCP mode you have selected is RTCP-XR, then the far end must support it.

Dead Call Detection

Specifies whether or not to use RTCP-based Dead Call Detection (DCD).

DCD is accomplished by monitoring incoming RTCP packets. If this feature is enabled, and if no RTCP packets are received from the peer for a period of 30 seconds, the call will be considered "dead", and disconnected. DCD should be disabled if the peer does not send RTCP packets.

Silence Suppression

Specifies where or not to use Voice Activity Detection and send PT13 packets when on.

  • If Silence Suppression is enabled, the Sonus SBC 1000/2000 monitors outgoing audio (towards the IP network). If silence is detected, voice packet transmission will cease to save network bandwidth. The enable setting saves network bandwidth, however, voice quality may be slightly degraded.
  • If Silence Suppression is disabled, voice packets are sent regardless of whether or not audio is present.

Reset SRTP Rollover Counter

For SRTP ROC, this configuration option specifies whether to reset the ROC or maintain the ROC.

Available options:

  • Start of Session (RFC 3711) - SBC will maintain the ROC, even if there is a key change, and
  • Upon New Remote Session Key - SBC will reset the ROC if the call is from Skype for Business Mediation Server and SRTP key is changed.

Default entry: Start of Session (RFC 3711).

This field is available only when the a Crypto Profile is selected from the Crypto Profile ID drop down box through creating or modifying a Media List. See Crypto Profile ID.


Gain Control - Field Definitions

Allows you to control the gain or loss (in decibels) to either the received or transmitted signals.

    • Negative values represent signal attenuation (lower volume).
    • Positive values represent signal amplification (higher volume).

Receive Gain

Specifies the gain or loss in decibels to apply to received signals. (Packet → PCM direction).

Transmit Gain

Specifies the gain or loss in decibels to apply to transmitted signals (PCM ← Packet direction).

Passthrough/Tone Detection - Field Definitions

Modem Passthrough

Specifies whether or not modem passthrough is enabled when using the G.711 codec.

If the user wants to support modem calls, this option should be Enabled. When Disabled, the Sonus SBC 1000/2000 does not distinguish between voice and modem calls. When Enabled, and the Sonus SBC 1000/2000 detects a modem call, it switches to Modem Passthrough mode (based on G.711 codec).

Fax Passthrough

Controls whether or not the Sonus SBC 1000/2000 supports G.711 faxing.

  • If you wish to force fax calls to use G.711 (uLaw/aLaw) codec, then Fax Passthrough must be Enabled. Also, G.711 must be the only codec in the Sonus SBC 1000/2000 Media List. In this configuration, the Sonus SBC 1000/2000 will only offer/accept G.711 in the reINVITE.
  • If you wish to support both G.711 and T.38 faxing simultaneously, the Fax Passthrough must be Enabled, and the Sonus SBC 1000/2000 must be configured with both G.711 and T.38 codecs. Which faxing type is selected will depend upon the codecs offered/accepted in the reINVITE.
  • If you wish to force fax calls to use T.38 codec, configure the Fax Passthrough to Disable. Sonus SBC 1000/2000 must be configured for both G.711 and T.38 codecs. In this configuration, the Sonus SBC 1000/2000 will only offer/accept T.38 in the reINVITE.

If your fax destination only offers T.38 in the reINVITE, then the Sonus SBC 1000/2000 must be configured for both G.711 and T.38. As noted above, T.38 fax negotiation is possible with Fax Passthrough configured to either Enable or Disable.

CNG Tone Detection

Specifies whether or not the Sonus SBC 1000/2000 system will detect Fax tones produced by the origination side fax machine. CNG tone detection is used when Fax calls are received from TDM to a Fax server and the voice call needs to be switched to a Fax call using T.38. If CNG tone detection is enabled, the Sonus SBC 1000/2000 detects the Fax tone from TDM and switches to Fax mode (it will initiate a re-INVITE with T.38 support to the Fax Server). If CNG tone detection is disabled, Sonus SBC 1000/2000 will pass-through the Fax tones to the Fax server and the Fax server will have to detect them and initiate a re-INVITE to switch to Fax mode with T.38.

Digit Relay - Field Definitions

Digit (DTMF) Relay Type

Specifies how DTMF digits are passed through the data network; as normal voice or encoded as specified in RFC 4733 (RFC 2833).

RFC 4733 (RFC 2833): When a DTMF digit is detected in the voice stream coming from the TDM side, the digit is removed from the voice stream (going to the IP network), and is sent out-of-band using the RFC 4733 (RFC 2833) mechanism.

As Voice: The DTMF digits are sent in the voice stream without any special treatment.

Digit Relay Payload Type

Specifies the payload type used for RFC 4733 (RFC 2833) packets. Available only when RFC 4733 (listed as RFC 2833) is specified for Relay Type.