Subject: [AVT] RFC2833: in-band or out-of-band

From: "Murat Artun" <[email-masked]>
Date: Tue, 16 May 2006 14:26:02 +0300

Hello,

I would be glad if sending RFC2833 type payload means sending the events or
tones in-band or out-band is clarified.

It seems as if it is in-band since RFC2833 type payload is carried in an RTP
packet like a normal voice data. But the sentence "If it uses some other,
out-of-band mechanism for signaling line conditions, it does not have to
implement the other events." from RFC2833, page 5, sounds as if RFC2833
payload is considered to be out-of-band.

-- 
M u r at  A r t u n, MSc.
   Software Engineer
_______________________________________________
Audio/Video Transport Working Group
[email-masked]
https://www1.ietf.org/mailman/listinfo/avt

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From: "Tom-PT Taylor" <[email-masked]>
Date: Tue, 16 May 2006 09:55:58 -0400

Classically, "out-of-band" meant that the signalling was undetectable by 
user equipment because it was outside the frequency range allocated to 
transport of voice. Since in the IP world we are talking packet streams 
rather than frequency ranges, the term won't have the same meaning. I'd 
suggest the most common usage, and the usage intended in RFC 2833 and 
certainly in RFC 2833bis, is that "out-of-band" is equivalent to "not in 
the media path".

The phrase you quote can actually be interpreted to mean (as I think it 
meant to say) that the line conditions pass in the signalling path 
rather than the media path.

Murat Artun wrote:
> ------------------------------------------------------------------------
>

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From: [email-masked]
Date: Wed, 17 May 2006 09:51:00 +0200

Agree to Tom.
=>
(1) RTP Inband
      = "events or tones" carried in RTP packets with same PT as media
(2) RTP Ouf-of-Band (RFC2833)
      = "events or tones" carried in RTP packets with separate PT as media

These are bearer-coupled transfer methods.
Then there are typically also "call/session control protocol" related
transfer methods (which often called Out-of-Band, too):

(3)   OoB using call/session control signaling (and RTP bearers):
            OoB with SIP (-> e.g. SIP INFO or SIP NOTIFY)
            OoB with H.323 (H.225.0/H.245)
            OoB with BICC
            OoB with ...

Albrecht

PS
Like to add also a pointer to correspondent ETSI terminology concerning
H.248-controlled RTP endpoints and digit transfer.
   see: ETSI ES 283 012 (12/06): "TISPAN NGN Release 1; Trunking Gateway
   Control Procedures for interworking between NGN and External CS
   Networks".
   => Annex A: DTMF Handling

                      "Tom-PT Taylor"                                                                                              
                      <[email-masked]         To:      Murat Artun <[email-masked]>                                         
                      om>                      cc:      [email-masked]                                                               
                                               Subject: Re: [AVT] RFC2833: in-band or out-of-band                                  
                      16.05.2006 15:55

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From: "Tom-PT Taylor" <[email-masked]>
Date: Wed, 17 May 2006 09:35:19 -0400

Actually, you and I differ., but I can't see that it matters. I would 
consider RFC 2833 packets to be in-band because they follow the media path.