What is difference between dtmf relay rtp-nte and dtmf h245-signal ??



  • According to Cisco:

    "Using Named Telephone Events (NTEs). Using NTE to
    relay DTMF tones provides a standardized means of transporting DTMF
    tones in RTP packets according to section 3 of RFC 2833, RTP Payload for DTMF Digits, Telephony Tones and Telephony Signals,
    developed by the Internet Engineering Task Force (IETF) Audio/Video
    Transport (AVT) working group. RFC 2833 defines formats of NTE RTP
    packets used to transport DTMF digits, hookflash, and other telephony
    events between two peer endpoints. With the NTE method, the endpoints
    perform per-call negotiation of the DTMF relay method. They also
    negotiate to determine the payload type value for the NTE RTP packets.

     Cisco H.323 gateways advertise capabilities using the H.245 capabilities
    messages. By default, they advertise that they can receive all DTMF
    relay modes. If the capabilities of the remote gateway do not match, the
    Cisco H.323 gateway transmits DTMF tones as in-band voice. Configuring
    DTMF relay on the Cisco H.323 gateway sets preferences for how the
    gateway handles DTMF transmission. If multiple methods are configured,
    the priority is as follows:

    • Cisco RTP
    • RTP NTE
    • H.245 signal
    • H.245 alphanumeric

    H.245 signal or alphanumeric—These methods separate DTMF digits from the
    voice stream and send them through the H.245 signaling channel instead
    of through the RTP channel. The tones are transported in H.245 User
    Input Indication messages. The H.245 signaling channel is a reliable
    channel, so the packets that transport the DTMF tones are guaranteed to
    be delivered. However, because of the overhead of using a reliable
    protocol, and depending on network congestion conditions, the DTMF tones
    may be slightly delayed. All H.323 version 2 compliant systems are
    required to support the “h245-alphanumeric” method, while support of the
    “h245-signal” method is optional.

    Matthew Berry  |  +1.612.567.CCIE (2243)Web: http://ciscovoiceguru.com
    Twitter: http://twitter.com/ciscovoiceguru

    On Aug 14, 2012, at 12:44 AM, wish4zain <[email protected]> wrote:
    What is difference between dtmf relay rtp-nte and dtmf h245-signal ??

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