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Re: [MMUSIC] Comments on draft-rosenberg-mmusic-ice-nonsip



I think the real meta-question on this draft, is whether:

   a. it is the same functionality as ICE, but not tied to SIP
   b. it is (a) plus a subsetting, removing features that we think only 
SIP needs


The list of things in the (b) bucket that I removed were:

   1. multiple streams
   2. multiple components per stream
   3. updating ICE parameters mid-negotiation
   4. restarting ICE
   5. role conflict detection
   6. ICE mismatches
   7. default candidates
   8. ice-lite
   9. forking support
   10. frozen algorithm
   11. remote candidates mechanism


So first we need to decide path a or b, and then we can discuss which of 
the above get included or not.

few more comments below:

Philip Matthews wrote:
> Below are some comments on this draft. I have grouped the comments by 
> subject matter.
> 
> Comments on the subset of ICE chosen:
> * I think this draft should allow multiple streams between the two 
> clients. I feel this is useful in non-SIP contexts. For example, my 
> draft draft-matthews-p2psip-id-loc requires multiple streams for non-SIP 
> purposes. I suggest this draft simply point out the simplifications that 
> occur if there is only one stream.
> 
> 
> Comments on the MIME object:
> * I think this draft should not require the MIME object of section 15, 
> but simply present it as one possible encoding. The draft should instead 
> list the parameters that ICE needs as input, and allow protocols to use 
> other encodings instead. Protocols may also derive some of these 
> ICE-related parameters from other fields in their protocol messages, 
> rather than pass them explicitly.
> For example, right now the HIP work is proposing to use an encoding that 
> is more consistent with HIP. HIP is a binary protocol, so a text-based 
> encoding seems a bit out-of-place. Moreover, the HIP work is proposing 
> to not generate an ICE-specific username fragment and password, but use 
> the Host Identity Tag (HIT) as the username fragment, and the keying 
> material derived from the Diffie-Helmman exchange as the password. Thus 
> these fields of the MIME object are not needed for HIP.

OK. I got a few folks that said they hated this MIME thing. THe 
intention was that it was optional - there if you want it. I think it 
would be a fine idea to have a section that also lists the params you'd 
need to include if you didn't use the MIME object.

> 
> 
> Comments on Terminology:
> * I dislike the term "session protocol". In SIP/SDP, it is the direct 
> connection which is the "session", not the signaling protocol, so the 
> "session protocol" should be the protocol that runs over the direct 
> connection. I suggest that you replace the sentence "NICE works only 
> with protocols that fit the pattern of a session protocol" with "NICE 
> only works with signaling protocols that have a rendezvous mechanism".

OK.

> 
> * In section 2, the document talks about establishing sessions between 
> "hosts". I think it should instead talk about sessions between clients 
> or protocol instances or similar.
> 
> * The document introduces the terms "Initiate Message/Accept Message" 
> and "Initiator/Responder" in place of ICE's "Offer/Answer" and 
> "Offerer/Answerer". Though the new terms might be better than the 
> existing terms, I think it will just be confusing to have to different 
> sets of terms for the same concept. Anyone who implements NICE and any 
> protocol designers who use NICE will have to at least skim 
> draft-ietf-mmusic-ice and become familiar with the Offer/Answer 
> terminology there, so I don't see the point of introducing new terminology.

Hmm, well I thought it was confusing to use the same terms when this is 
not based on O/A anymore.

-Jonathan R.
-- 
Jonathan D. Rosenberg, Ph.D.                   499 Thornall St.
Cisco Fellow                                   Edison, NJ 08837
Cisco, Voice Technology Group
jdrosen at cisco.com
http://www.jdrosen.net                         PHONE: (408) 902-3084
http://www.cisco.com
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