Re: [AVTCORE] WGLC on draft-ietf-avtcore-ecn-for-rtp-04 - more
Roni Even <Even.roni@huawei.com> Thu, 27 October 2011 13:59 UTC
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Date: Thu, 27 Oct 2011 15:53:14 +0200
From: Roni Even <Even.roni@huawei.com>
In-reply-to: <4EA95E3C.2020907@ericsson.com>
To: 'Magnus Westerlund' <magnus.westerlund@ericsson.com>
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Subject: Re: [AVTCORE] WGLC on draft-ietf-avtcore-ecn-for-rtp-04 - more
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Magnus, I am OK with your answers Roni > -----Original Message----- > From: Magnus Westerlund [mailto:magnus.westerlund@ericsson.com] > Sent: Thursday, October 27, 2011 3:36 PM > To: Roni Even > Cc: avt@ietf.org > Subject: Re: [AVTCORE] WGLC on draft-ietf-avtcore-ecn-for-rtp-04 - more > > Hi Roni, > > Thanks for the feedback. > > > On 2011-10-22 14:05, Roni Even wrote: > > > > 1. In section 7.2 "All session participants connected over the > > same transport will need to use the same initiation method." maybe > say > > MUST use instead of will need to use. > > sure. > > > > > 2. In section 7.2 " If support for both in-band and out-of-band > > mechanisms is signalled, the sender SHOULD try ECN negotiation using > > STUN with ICE first, and if it fails, fallback to negotiation using > RTP > > and RTCP ECN feedback" I think that it should say that the sender > should > > offer ice initialization method before rtp. > > I would suggest to formulate this as: > > If support for both in-band and out-of-band mechanisms are signalled, > the sender when negotiating SHOULD offer detection of ECT using STUN > with ICE with higher priority than detection of ECT using RTP and RTCP. > > > > > > 3. In section 7.2.1 y ou refer not reference the keep-alive RFC > > Why do you think we should reference RFC 6263? Is is because we discuss > which packets would have least impact on the media flow when used as > ECT > probes? IF that is the reasons I don't think RFC6263 has much to offer. > The outcome of this document is that nothing short of real RTP or RTCP > packets work well for keep-alive. And in this context of ECN we can't > use the RTCP packets. > > > > > 4. In section 7.2.1 Generating RTCP ECN Feedback it says > > "Reception of subsequent ECN-CE marked packets MUST result in > > additional early or immediate ECN". Why use MUST and not SHOULD since > > there is an exception case following the sentence. > > Because if we use SHOULD then one might consider that additional > exceptions than just that one exists. And that is not the case. If you > use a method that requires timely feedback, then you better send that > feedback. > > > > > 5. In section 7.2.1 "ECN initiation is considered to have > failed > > at the instant when a ny RTP s an RTCP packet that doesn't contain > an > > RTCP ECN feedback report or ECN summary report " The RTCP ECN > feedback > > report may be missing for other reasons like no timely response or > using > > AVP profile. > > I think you are misunderstanding what was written, maybe because of the > bad formulation in the sentence. I have rewritten this to: > > ECN initiation is considered to have failed at the instant the > initiating RTP sender received an RTCP packet that doesn't contain an > RTCP ECN feedback report or ECN summary report from any RTP session > participant that has an RTCP RR with an extended RTP sequence number > field that indicates that it should have received multiple (>3) ECT > marked RTP packets. > > Is that clearer? > > > > > > 6. In section 7.3.3 receiver driven congestion control you > mention > > layered codecs as an option I think that using ccm tmbbr is more > useful > > when there are no layered codecs in use (more common today) and > should > > be mentioned in this section. > > I am very split about discussing this. I know there exist > implementations that uses TMMBR as primary congestion control. However, > RFC 5104 hasn't specified it in that way. > > I also see an issue with bringing it up in this context, namely that we > bless this without any specification or requirements on the solution. > For example how responsive to congestion is the usage of TMMBR. One > parameter is the AVPF operations mode and due to this RTCP bandwidths. > another is the algorithm determining the appropriate bit-rate. > > I know that the multicast scalable encoding share similar concerns but > there we have even less alternatives. > > I think reformulating the introduction of the section to make clear > that > this is just an example of Receiver driven congestion control is most > appropriate. > > > In a receiver driven congestion control mechanism, the receivers can > react to the ECN-CE marks themselves without providing ECN-CE feedback > to the sender. This may allow faster response than sender-driven > congestion control in some circumstances and also scale to large number > of receivers and multicast usage. One example of receiver-driven > congestion control is implemented by providing the content in a layered > way, with each layer providing improved media quality but also > increased > bandwidth usage. > > > > > 7.&nbs ; In section 10.6 you use the wrong range definition "From > RFC > > 5389: STUN Attribute types in the first half of the > > comprehension-requiredrange (0x0000 - 0x3FFF) and in the first half > of > > the comprehension- optional range (0x8000 - 0xBFFF) are assigned by > IETF > > Review" > > > > Good catch. > > Thanks > > Magnus Westerlund > > ---------------------------------------------------------------------- > Multimedia Technologies, Ericsson Research EAB/TVM > ---------------------------------------------------------------------- > Ericsson AB | Phone +46 10 7148287 > Färögatan 6 | Mobile +46 73 0949079 > SE-164 80 Stockholm, Sweden| mailto: magnus.westerlund@ericsson.com > ----------------------------------------------------------------------
- [AVTCORE] WGLC on draft-ietf-avtcore-ecn-for-rtp-… Roni Even
- Re: [AVTCORE] WGLC on draft-ietf-avtcore-ecn-for-… Belling, Thomas (NSN - DE/Munich)
- Re: [AVTCORE] WGLC on draft-ietf-avtcore-ecn-for-… Magnus Westerlund
- Re: [AVTCORE] WGLC on draft-ietf-avtcore-ecn-for-… Qin Wu
- Re: [AVTCORE] WGLC on draft-ietf-avtcore-ecn-for-… Belling, Thomas (NSN - DE/Munich)
- Re: [AVTCORE] WGLC on draft-ietf-avtcore-ecn-for-… Qin Wu
- Re: [AVTCORE] WGLC on draft-ietf-avtcore-ecn-for-… Bill Ver Steeg (versteb)
- Re: [AVTCORE] WGLC on draft-ietf-avtcore-ecn-for-… Dan Wing
- Re: [AVTCORE] WGLC on draft-ietf-avtcore-ecn-for-… Piers O'Hanlon
- Re: [AVTCORE] WGLC on draft-ietf-avtcore-ecn-for-… Qin Wu
- Re: [AVTCORE] WGLC on draft-ietf-avtcore-ecn-for-… Magnus Westerlund
- Re: [AVTCORE] WGLC on draft-ietf-avtcore-ecn-for-… Magnus Westerlund
- Re: [AVTCORE] WGLC on draft-ietf-avtcore-ecn-for-… Magnus Westerlund
- Re: [AVTCORE] WGLC on draft-ietf-avtcore-ecn-for-… Dan Wing
- Re: [AVTCORE] WGLC on draft-ietf-avtcore-ecn-for-… Piers O'Hanlon
- [AVTCORE] 答复: WGLC on draft-ietf-avtcore-ecn-for-… Qin Wu
- Re: [AVTCORE] WGLC on draft-ietf-avtcore-ecn-for-… Roni Even
- Re: [AVTCORE] WGLC on draft-ietf-avtcore-ecn-for-… Roni Even
- Re: [AVTCORE] WGLC on draft-ietf-avtcore-ecn-for-… Belling, Thomas (NSN - DE/Munich)
- Re: [AVTCORE] WGLC on draft-ietf-avtcore-ecn-for-… Magnus Westerlund
- Re: [AVTCORE] WGLC on draft-ietf-avtcore-ecn-for-… Roni Even
- Re: [AVTCORE] WGLC on draft-ietf-avtcore-ecn-for-… Bill Ver Steeg (versteb)
- Re: [AVTCORE] WGLC on draft-ietf-avtcore-ecn-for-… Piers O'Hanlon
- Re: [AVTCORE] WGLC on draft-ietf-avtcore-ecn-for-… Bill Ver Steeg (versteb)
- Re: [AVTCORE] WGLC on draft-ietf-avtcore-ecn-for-… Piers O'Hanlon