The SBC Core supports playing tones locally based on SIP Alert-Info header using the IP Signaling Profile (IPSP) acceptAlertInfo flag. Alert-Info header triggers tone generation when a SIP backward response message (180 with or without SDP) is received. The 180 ringing message with Alert-info header can be received before or after cut through. The tone-id included in Alert-Info header is used as a key word in the tone package locally configured on the SBC. This feature is supported over the SIP and SIP-I interface.The ISUP MIME body parameters do not have any interaction with Alert-Info header when this feature is used.

Alert-Info header as per RFC-3261 can be received in an INVITE/UPDATE request or in a 180 ringing message. The SBC supports processing of Alert-Info header only in 180 ringing message and plays the tone based on the tone-id as per the format specified by Legacy MS Domain (LMSD) received in the Alert-Info header.

This feature is enabled by enabling the IPSP flag "Accept Alert Info". When this flag is enabled and the Accept Alert Info header is received in a 180 ringing message in the format specified by LMSD specification, SBC processes the header and plays the tone locally. By default, this flag is set to disable for backward compatibility purposes.

The format specified in the Legacy MS domain is found in the document 3GPP2 X.S0025-0, Version 1.0, Version Date: February, 2006

 

Format of the Alert-info header: The Alert-Info header contains a URI address of <http:/LMSD/tone?sig-id=tone>, where "sig-id=" indicates the value of tone to be provided.

The tone as defined above is used as a string to match the tone type specified in the "Signaling Tone Package" associated with the "Tone and Announcement Profile" selected by the PSX for the call. Additionally, it can also be in the format <http:/null>,  indicating that any existing media/tone being played is stopped.

Refer to Common IP Attributes - Flags and Common IP Attributes - Flags for CLI and EMA changes respectively.

Alert-Info header Play Tone

 Various tones can be received in a LMSD-based CDMA network, including, but not limited to, the following:

  • rt - ring tone
  • bt - busy tone
  • ct -  congestion tone,
  • cmft - comfort tone, and
  • cr - caller waiting

Tones that are not configured in the Signaling Tone Package for the desired Trunk Group  are mapped to default ringback tone (if configured).

Alert-Info header Stop Tone

A tone based on Alert-Info header can be stopped based on following conditions:

  • 180 Ringing is received with Alert-Info header as <http:/null>
  • 180 Ringing is received without Alert-Info header

  • 183 Progress is received with or without Alert-Info header

  • 200 OK is received with or without Alert-Info header

If a signaling tone is not configured on the SBC, the default tone is used.

 

 

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