[VoiceOps] RTP End?

[Marco Teixeira]

Hi John,

So what happens when g729 is used with VAD and the far end media gw
interrupts sending rtp packets on silence detection ?
Or am i missing something ?

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Cumprimentos / Best regards

Marco Teixeira
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skype: admin-marcoteixeira.com
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On Thu, Sep 13, 2012 at 4:57 PM, John S. Robinson <jsr at communichanic.com>wrote:

>  Clint -- The answer to this is fairly straightforward.
> *
> **If* your Empirix Hammer is providing media quality monitoring, it *must*rely on the the actual RTP media stream that it is monitoring.
>
> A media stream is defined as Source IP:Port plus Destination IP:port plus
> *SSRC.   *SSRC is often over overlooked, but strict media gateways or
> media relays *may* refuse to process any further RTP packets when SSRC or
> Source IP:port changes without any new SDP offer-answer.
>
> RTP Start is established when the the *first *packet is received on the *
> Destination* IP:port negotiated by SDP offer:answer.   At that time the
> RTP monitor (or any strict media handler) *learns* the *Source* IP:Port,
> and the SSRC
>
> As someone else has pointed out, there is no "RTP end" packet.  So "RTP
> end" is declared when there are no further media packets received on the
> established
> stream, defined by Source IP:Port plus Destination IP:port *plus* *SSRC*.
> This may happen at any time in an established session.   If something "goes
> wrong" in a media stream, the "RTP end" *may *be declared well before any
> sip method (usually BYE) which ends the session.    This explains why you
> "have seen this many times preceeding a BYE - or even without a BYE."
> Any "RTP end" which occurs substantially before a BYE *without* an almost
> immediate new "RTP Start" indicates the potential media failure.   If that
> happens, the media failure may be the root cause of the BYE.   In that
> case, you may be loosing revenue.
>
> None of this is in any way related to presence or absence of RTCP.
>
> Hope this helps.   If you would like any further discussion, please
> contact me privately.
>
> Best regards,
>
> Communichanic Consultants, Inc
> John S. Robinson <jsr at communichanic.com>, President
>
>
>
>
> On 9/12/2012 17:25, Clint Mojzes wrote:
>
>  We are using a tool called Empirix Hammer to analyze and report on our
> network traffic. This tool as uncovered something that it calls “RTP End”
> and I’m trying to get a better definition of what it means. I haven’t been
> able to find anything online, including RFCs etc. Basically when the Hammer
> see this special packet, it is when a phone or media gateway is tearing
> down a call. Logically speaking it is identifying the end of a media
> stream, but I’m looking for a technical definition. Can anyone provide any
> insight?****
>
> ** **
>
> Thanks,****
>
> ** **
>
> -Clint****
>
> ** **
>
> * *
>
>
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