Re: [MMUSIC] Offer/Answer PT Questions
"Makaraju, Raju (Nokia - US)" <raju.makaraju@nokia.com> Mon, 22 February 2016 23:29 UTC
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From: "Makaraju, Raju (Nokia - US)" <raju.makaraju@nokia.com>
To: "md3135@att.com" <md3135@att.com>, "christer.holmberg@ericsson.com" <christer.holmberg@ericsson.com>, "pkyzivat@alum.mit.edu" <pkyzivat@alum.mit.edu>, "mmusic@ietf.org" <mmusic@ietf.org>
Thread-Topic: [MMUSIC] Offer/Answer PT Questions
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Date: Mon, 22 Feb 2016 23:29:24 +0000
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References: <E42CCDDA6722744CB241677169E8365615E419C0@MISOUT7MSGUSRDB.ITServices.sbc.com> <56C89F86.7020401@alum.mit.edu> <7594FB04B1934943A5C02806D1A2204B37E35E33@ESESSMB209.ericsson.se> <CAD5OKxsDGhSA1WpzVVEvdd0CQdbnFn+ST+ZP_=aYVWBVdKKs4g@mail.gmail.com> <56CB6DB6.30802@alum.mit.edu> <7594FB04B1934943A5C02806D1A2204B37E36086@ESESSMB209.ericsson.se>, <E42CCDDA6722744CB241677169E8365615E45C92@MISOUT7MSGUSRDB.ITServices.sbc.com>
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Subject: Re: [MMUSIC] Offer/Answer PT Questions
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+1 for fixing it to allow unambigous payload reuse. Thanks Christer, for bringing it up. BR Raju ------ Original message------ From: DOLLY, MARTIN C Date: Mon, Feb 22, 2016 4:43 PM To: Christer Holmberg;Paul Kyzivat;mmusic@ietf.org; Subject:Re: [MMUSIC] Offer/Answer PT Questions Paul, I agree with Christer, this needs to be fixed. We are doing interop testing with other carriers for VoIP interconnection, and this is a major issue. Fixing this would help accelerate VoIP interconnection. Regards, Martin -----Original Message----- From: mmusic [mailto:mmusic-bounces@ietf.org] On Behalf Of Christer Holmberg Sent: Monday, February 22, 2016 3:42 PM To: Paul Kyzivat <pkyzivat@alum.mit.edu>; mmusic@ietf.org Subject: Re: [MMUSIC] Offer/Answer PT Questions Hi, >> One thing that bothered me here is that PT cannot be reused for the >> duration of the session. It is probably safe to reuse the PT after >> session modification if PT is no longer used. I always felt that >> dynamic PT reuse criteria were much stricter then realistically possible or needed. >... >> I think the most important criteria here is that there should be no >> ambiguity regarding how an RTP packet with particular PT should be >> decoded. If it is guaranteed that there are no packets sent between >> Alice and Bob with PT 111 over some reasonable time interval (couple >> of network round trip times), then PT 111 can be safely reused. If, >> in this scenario Bob's end point knows that it was not sending >> anything with payload 111 recently, then it can safely reuse this payload. >> Alice could not be sending anything with payload 111 since Bob did >> not accept it previously. On the other hand, Bob must not reuse PT >> 100 for, let's say, CN, since there are packets with this payload in >> flight and this will create decoding ambiguity. To conclude, an end >> point should be able to safely reuse any PT that it is not currently >> accepting or was not sending or accepting for at least a few network round trip intervals. > > I agree that this is how it *should* be. I don't know if we can change > this safely or not. It seems likely to me that some implementations might be freaked out by this. It is worth discussion. > > There are cases where it really isn't feasible to meet the current > requirement. In particular, when a transfer is done via 3pcc the transferee won't know the history of past PT usage. So I expect in cases such cases the rule is commonly broken. > > Coming up with clear rules for when PTs can be recycled could be a challenge. Well, I think we have to try, because these kind of issues keep causing problems. The fact that something may freak about because we fix it is not a reason for not fixing it :) Regards, Christer _______________________________________________ mmusic mailing list mmusic@ietf.org https://www.ietf.org/mailman/listinfo/mmusic _______________________________________________ mmusic mailing list mmusic@ietf.org https://www.ietf.org/mailman/listinfo/mmusic
- [MMUSIC] Offer/Answer PT Questions DOLLY, MARTIN C
- Re: [MMUSIC] Offer/Answer PT Questions Paul Kyzivat
- Re: [MMUSIC] Offer/Answer PT Questions Christer Holmberg
- Re: [MMUSIC] Offer/Answer PT Questions Roman Shpount
- Re: [MMUSIC] Offer/Answer PT Questions Christer Holmberg
- Re: [MMUSIC] Offer/Answer PT Questions Paul Kyzivat
- Re: [MMUSIC] Offer/Answer PT Questions Paul Kyzivat
- Re: [MMUSIC] Offer/Answer PT Questions Paul Kyzivat
- Re: [MMUSIC] Offer/Answer PT Questions Roman Shpount
- Re: [MMUSIC] Offer/Answer PT Questions DOLLY, MARTIN C
- Re: [MMUSIC] Offer/Answer PT Questions Roman Shpount
- Re: [MMUSIC] Offer/Answer PT Questions DOLLY, MARTIN C
- Re: [MMUSIC] Offer/Answer PT Questions Paul Kyzivat
- Re: [MMUSIC] Offer/Answer PT Questions Roman Shpount
- Re: [MMUSIC] Offer/Answer PT Questions Colin Perkins
- Re: [MMUSIC] Offer/Answer PT Questions Drage, Keith (Nokia - GB)
- Re: [MMUSIC] Offer/Answer PT Questions Christer Holmberg
- Re: [MMUSIC] Offer/Answer PT Questions Paul Kyzivat
- Re: [MMUSIC] Offer/Answer PT Questions Paul Kyzivat
- Re: [MMUSIC] Offer/Answer PT Questions Ben Campbell
- Re: [MMUSIC] Offer/Answer PT Questions Christer Holmberg
- Re: [MMUSIC] Offer/Answer PT Questions Roman Shpount
- Re: [MMUSIC] Offer/Answer PT Questions Paul Kyzivat
- Re: [MMUSIC] Offer/Answer PT Questions Ben Campbell
- Re: [MMUSIC] Offer/Answer PT Questions Makaraju, Raju (Nokia - US)
- Re: [MMUSIC] Offer/Answer PT Questions Colin Perkins
- Re: [MMUSIC] Offer/Answer PT Questions Christer Holmberg
- Re: [MMUSIC] Offer/Answer PT Questions Dale R. Worley
- Re: [MMUSIC] Offer/Answer PT Questions Roman Shpount
- Re: [MMUSIC] Offer/Answer PT Questions Roman Shpount
- Re: [MMUSIC] Offer/Answer PT Questions Paul Kyzivat
- Re: [MMUSIC] Offer/Answer PT Questions Drage, Keith (Nokia - GB)
- Re: [MMUSIC] Offer/Answer PT Questions Paul Kyzivat
- Re: [MMUSIC] Offer/Answer PT Questions Christer Holmberg
- Re: [MMUSIC] Offer/Answer PT Questions Christer Holmberg
- Re: [MMUSIC] Offer/Answer PT Questions Roman Shpount