Name: Miguel Angel Reina Ortega

Email: miguelangel.reinaortega&etsi.org

Media type name: audio

Media subtype name: TETRA_ACELP_BB

Required parameters:

   rate: RTP timestamp clock rate (samples/second), which is equal to
      the sampling rate. The typical rate is 8000; other rates may be
      specified.

Optional parameters:

   ptime: packet time in milliseconds (non-negative integer) for the 
      media represented in a packet made up of one full TETRA speech 
      frame.

   maxptime: maximum amount of media in milliseconds (non-negative 
      integer) that can be encapsulated in each packet – this is the 
      framing rate.

   payload-type: list of active payload types supported in a comma 
      separated list from {0, … , 3} as per ETSI TS 100 392-19-2 
      clause A.3.7

   encryption-mode: list of encryption modes that can be used in a 
      comma separated list from {0,1}, as per ETSI TS 100 392-19-2 
      clause A.3.7

   If the values of these optional parameters are omitted then the 
   following values shall be used.

   ptime: 30

   maxptime: 30

   payload-type: 0 (where 0 represents a particular format of the 
      payload type (see ETSI TS 100 392-19-2 clause A.4.2)

   encryption-mode: 0 (where 0 represents a no end-to-end encryption 
      mode, (see ETSI TS 100 392-19-2 clause A.4.2)

Encoding considerations: “framed” (transport_provided)

Security considerations: RTP packets using the payload format defined
   in this specification are subject to the general security 
   considerations discussed in RFC 3550 and in any used profile, like
   AVP [RFC 3551] or SAVP [RFC 3711]. As this format transports 
   encoded speech, the main security issues include confidentiality, 
   authentication, and integrity of the speech itself. The payload 
   format itself does not have any built-in security mechanisms, 
   although any audio media and control information carried may be 
   separately ciphered.

   External mechanisms, such as SRTP [RFC 3711], may be used for the 
   security functionality. The appropriate mechanisms to provide 
   security to RTP and the payloads following this memo may vary 
   depending on the application, the transport, and the signaling 
   protocol employed. Security mechanisms that may be used are TLS 
   [RFC 4346] (RTP over TCP) and IPsec [RFC 4301], but other 
   alternatives may also exist.

   This media type does not employ compression.

   The media packets in this payload format do not contain any 
   executable content. This payload format does contain the option to
   carry ‘stolen’ user plane packets instead of the media packets to 
   allow certain activities such as encryption synchronization, as 
   described in ETSI EN 300 392-2. However, these packets will be 
   discarded if not understood by the receiving endpoint and do not 
   include any executable content. The payload format does not 
   exhibit any significant non-uniformity in the receiver side 
   computational complexity for packet processing, and thus is 
   unlikely to pose a denial-of-service threat due to the receipt of 
   abnormal data.

   It is recommended that the payload should be at a minimum 
   integrity protected in order to prevent payload modifications that 
   may impact downstream terminal behaviour.

Interoperability considerations: This media type carries 
   TETRA_ACELP_BB encoded audio framed as per the TETRA speech over 
   mission critical broadband systems specification (ETSI TS 100 
   392-19-2) to allow interoperability between network operators 
   independent of the network manufacturer.

   The encoding of the audio part of the payload is described in ETSI 
   EN 300 395-2:
	
   "Terrestrial Trunked Radio (TETRA); Speech codec for full-rate 
    traffic channel; Part 2: TETRA codec".

Published specification: ETSI TS 100 392-19-2 v1.1.1: “Terrestrial 
   Trunked Radio (TETRA); Voice plus Data (V+D); Sub-part 2: Format 
   for the transport of TETRA speech over mission critical broadband 
   systems”.

   ETSI EN 300 395-2 v1.3.1: "Terrestrial Trunked Radio (TETRA); 
   Speech codec for full-rate traffic channel; Part 2: TETRA codec".

   ETSI EN 300 392-2 v3.8.1: “Terrestrial Trunked Radio (TETRA); 
   Voice plus Data (V+D); Part 2 Air Interface (AI)”.

Applications which use this media: Devices or applications that send 
   or receive TETRA_ACELP_BB encoded audio over RTP/IP

Fragment identifier considerations: N/A

Restrictions on usage: This media type depends on RTP framing, and 
   hence is only defined for transfer via RTP (RFC 3550). Transfer 
   within other framing protocols is not defined at this time.

Additional information:

   1. Deprecated alias names for this type: N/A 
   2. Magic number(s): N/A 
   3. File extension(s): N/A 
   4. Macintosh file type code: N/A 
   5. Object Identifiers: N/A

General Comments:


Person to contact for further information:

   1. Name: Miguel Angel Reina Ortega
   2. Email: miguelangel.reinaortega&etsi.org

Intended usage: Common

Author/Change controller: ETSI TCCE WG4/ETSI